diff --git a/__tests__/purgecssDefault.test.js b/__tests__/purgecssDefault.test.js
index 8e3f4c80..76bc448c 100644
--- a/__tests__/purgecssDefault.test.js
+++ b/__tests__/purgecssDefault.test.js
@@ -288,6 +288,26 @@ describe('purge methods with files and default extractor', () => {
             expect(purgecssResult.includes('@keyframes rotateAni')).toBe(true)
         })
     })
+
+    // Font Face
+    describe('purge unused font-face', () => {
+        let purgecssResult
+        beforeAll(() => {
+            purgecssResult = new Purgecss({
+                content: [`${root}font_face/font_face.html`],
+                css: [`${root}font_face/font_face.css`],
+                fontFace: true
+            }).purge()[0].css
+        })
+        it("keep @font-face 'Cerebri Sans'", () => {
+            expect(purgecssResult.includes(`src: url('../fonts/CerebriSans-Regular.eot?')`)).toBe(
+                true
+            )
+        })
+        it("remove @font-face 'OtherFont'", () => {
+            expect(purgecssResult.includes(`src: url('xxx')`)).toBe(false)
+        })
+    })
 })
 
 describe('purge methods with raw content and default extractor', () => {
diff --git a/__tests__/test_examples/font_face/font_face.css b/__tests__/test_examples/font_face/font_face.css
index 31a29a46..16bd9b35 100644
--- a/__tests__/test_examples/font_face/font_face.css
+++ b/__tests__/test_examples/font_face/font_face.css
@@ -5,10 +5,18 @@
     src: url('../fonts/CerebriSans-Regular.eot?') format('eot'), url('../fonts/CerebriSans-Regular.otf') format('opentype'), url('../fonts/CerebriSans-Regular.svg#Cerebri_Sans') format('svg'), url('../fonts/CerebriSans-Regular.ttf') format('truetype'), url('../fonts/CerebriSans-Regular.woff') format('woff');
 }
 
+@font-face {
+    font-family: 'OtherFont';
+    font-weight: 400;
+    font-style: normal;
+    src: url('xxx')
+}
+
 .unused {
     color: black;
 }
 
 used {
     color: red;
-}
\ No newline at end of file
+    font-family: 'Cerebri Sans';
+}
diff --git a/__tests__/test_examples/keyframes/index.css b/__tests__/test_examples/keyframes/index.css
index 3b787be7..8166b694 100644
--- a/__tests__/test_examples/keyframes/index.css
+++ b/__tests__/test_examples/keyframes/index.css
@@ -1,3 +1,11 @@
+@-webkit-keyframes rotateAni {
+  from {
+    transform: rotate(0deg);
+  }
+  to {
+    transform: rotate(359deg);
+  }
+}
 @keyframes rotateAni {
   from {
     transform: rotate(0deg);
@@ -11,6 +19,16 @@
   animation: rotateAni 200ms ease-out both;
 }
 
+@-webkit-keyframes flashAni
+{
+  from, 50%, to {
+    opacity: 1;
+  }
+
+  25%, 75% {
+    opacity: 0;
+  }
+}
 @keyframes flashAni
 {
   from, 50%, to {
diff --git a/__tests__/test_examples/keyframes/keyframes.css b/__tests__/test_examples/keyframes/keyframes.css
index 08f19f1b..19dced24 100644
--- a/__tests__/test_examples/keyframes/keyframes.css
+++ b/__tests__/test_examples/keyframes/keyframes.css
@@ -20,4 +20,8 @@
     25%, 75% {
         opacity: 0.5;
     }
+}
+
+.flash {
+    animation: flash
 }
\ No newline at end of file
diff --git a/flow-typed/index.js b/flow-typed/index.js
index 3f275145..44249393 100644
--- a/flow-typed/index.js
+++ b/flow-typed/index.js
@@ -17,7 +17,8 @@ declare type Options = {
   info?: boolean,
   rejected?: boolean,
   legacy?: boolean,
-  keyframes?: boolean
+  keyframes?: boolean,
+  fontFace?: boolean
 }
 
 declare type ExtractorsObj = {
@@ -29,3 +30,8 @@ declare type ResultPurge = {
   file: ?string,
   css: string
 }
+
+declare type AtRules = {
+  keyframes: Array<Object>,
+  fontFace: Array<Object>
+}
\ No newline at end of file
diff --git a/lib/purgecss.es.js b/lib/purgecss.es.js
index d9e39ebc..859a217e 100644
--- a/lib/purgecss.es.js
+++ b/lib/purgecss.es.js
@@ -1 +1 @@
-import fs from"fs";import glob from"glob";import postcss from"postcss";import selectorParser from"postcss-selector-parser";function normalizeArray(t,e){for(var r=0,o=t.length-1;o>=0;o--){var n=t[o];"."===n?t.splice(o,1):".."===n?(t.splice(o,1),r++):r&&(t.splice(o,1),r--)}if(e)for(;r--;r)t.unshift("..");return t}var splitPathRe=/^(\/?|)([\s\S]*?)((?:\.{1,2}|[^\/]+?|)(\.[^.\/]*|))(?:[\/]*)$/,splitPath=function(t){return splitPathRe.exec(t).slice(1)};function resolve(){for(var t="",e=!1,r=arguments.length-1;r>=-1&&!e;r--){var o=r>=0?arguments[r]:"/";if("string"!=typeof o)throw new TypeError("Arguments to path.resolve must be strings");o&&(t=o+"/"+t,e="/"===o.charAt(0))}return t=normalizeArray(filter(t.split("/"),function(t){return!!t}),!e).join("/"),(e?"/":"")+t||"."}function normalize(t){var e=isAbsolute(t),r="/"===substr(t,-1);return(t=normalizeArray(filter(t.split("/"),function(t){return!!t}),!e).join("/"))||e||(t="."),t&&r&&(t+="/"),(e?"/":"")+t}function isAbsolute(t){return"/"===t.charAt(0)}function join(){return normalize(filter(Array.prototype.slice.call(arguments,0),function(t,e){if("string"!=typeof t)throw new TypeError("Arguments to path.join must be strings");return t}).join("/"))}function relative(t,e){function r(t){for(var e=0;e<t.length&&""===t[e];e++);for(var r=t.length-1;r>=0&&""===t[r];r--);return e>r?[]:t.slice(e,r-e+1)}t=resolve(t).substr(1),e=resolve(e).substr(1);for(var o=r(t.split("/")),n=r(e.split("/")),i=Math.min(o.length,n.length),a=i,s=0;s<i;s++)if(o[s]!==n[s]){a=s;break}var l=[];for(s=a;s<o.length;s++)l.push("..");return(l=l.concat(n.slice(a))).join("/")}var sep="/",delimiter=":";function dirname(t){var e=splitPath(t),r=e[0],o=e[1];return r||o?(o&&(o=o.substr(0,o.length-1)),r+o):"."}function basename(t,e){var r=splitPath(t)[2];return e&&r.substr(-1*e.length)===e&&(r=r.substr(0,r.length-e.length)),r}function extname(t){return splitPath(t)[3]}var path={extname:extname,basename:basename,dirname:dirname,sep:sep,delimiter:delimiter,relative:relative,join:join,isAbsolute:isAbsolute,normalize:normalize,resolve:resolve};function filter(t,e){if(t.filter)return t.filter(e);for(var r=[],o=0;o<t.length;o++)e(t[o],o,t)&&r.push(t[o]);return r}var substr="b"==="ab".substr(-1)?function(t,e,r){return t.substr(e,r)}:function(t,e,r){return e<0&&(e=t.length+e),t.substr(e,r)},defaultOptions={css:[],content:[],extractors:[],whitelist:[],output:void 0,stdout:!1,info:!1,rejected:!1,legacy:!1,keyframes:!1},IGNORE_ANNOTATION="purgecss ignore",CONFIG_FILENAME="purgecss.config.js",ERROR_CONFIG_FILE_LOADING="Error loading the config file",ERROR_MISSING_CONTENT="No content provided.",ERROR_MISSING_CSS="No css provided.",ERROR_EXTRACTER_FAILED="The extractor has failed to extract the selectors.",ERROR_OPTIONS_TYPE="Error Type Options: expected an object",ERROR_OUTPUT_TYPE="Error Type option output: expected a string",ERROR_EXTRACTERS_TYPE="Error Type option extractors: expected an array",ERROR_WHITELIST_TYPE="Error Type option whitelist: expected an array",ERROR_WHITELIST_PATTERNS_TYPE="Error Type option whitelistPatterns: expected an array",ERROR_STDOUT_TYPE="Error Type option stdout: expected a boolean",ERROR_INFO_TYPE="Error Type option info: expected a boolean",ERROR_REJECTED_TYPE="Error Type option rejected: expected a boolean",CSS_WHITELIST=["*","::-webkit-scrollbar","::selection",":root","::before","::after"],SELECTOR_STANDARD_TYPES=["class","id","universal","pseudo"],_typeof="function"==typeof Symbol&&"symbol"==typeof Symbol.iterator?function(t){return typeof t}:function(t){return t&&"function"==typeof Symbol&&t.constructor===Symbol&&t!==Symbol.prototype?"symbol":typeof t},classCallCheck=function(t,e){if(!(t instanceof e))throw new TypeError("Cannot call a class as a function")},createClass=function(){function t(t,e){for(var r=0;r<e.length;r++){var o=e[r];o.enumerable=o.enumerable||!1,o.configurable=!0,"value"in o&&(o.writable=!0),Object.defineProperty(t,o.key,o)}}return function(e,r,o){return r&&t(e.prototype,r),o&&t(e,o),e}}(),toConsumableArray=function(t){if(Array.isArray(t)){for(var e=0,r=Array(t.length);e<t.length;e++)r[e]=t[e];return r}return Array.from(t)},DefaultExtractor=function(){function t(){classCallCheck(this,t)}return createClass(t,null,[{key:"extract",value:function(t){return t.match(/[A-Za-z0-9_-]+/g)}}]),t}(),LegacyExtractor=function(){function t(){classCallCheck(this,t)}return createClass(t,null,[{key:"extract",value:function(t){return t.split(/[^a-z]/g)}}]),t}(),Purgecss=function(){function t(e){classCallCheck(this,t),this.atRules={keyframes:{}},"string"!=typeof e&&void 0!==e||(e=this.loadConfigFile(e)),this.checkOptions(e),this.options=Object.assign(defaultOptions,e)}return createClass(t,[{key:"loadConfigFile",value:function(t){var e=void 0===t?CONFIG_FILENAME:t,r=void 0;try{var o=path.resolve(process.cwd(),e);r=require(o)}catch(t){throw new Error(ERROR_CONFIG_FILE_LOADING+t.message)}return r}},{key:"checkOptions",value:function(t){if("object"!==(void 0===t?"undefined":_typeof(t)))throw new TypeError(ERROR_OPTIONS_TYPE);if(!t.content||!t.content.length)throw new Error(ERROR_MISSING_CONTENT);if(!t.css||!t.css.length)throw new Error(ERROR_MISSING_CSS);if(t.output&&"string"!=typeof t.output)throw new TypeError(ERROR_OUTPUT_TYPE);if(t.extractors&&!Array.isArray(t.extractors))throw new TypeError(ERROR_EXTRACTERS_TYPE);if(t.whitelist&&!Array.isArray(t.whitelist))throw new TypeError(ERROR_WHITELIST_TYPE);if(t.stdout&&"boolean"!=typeof t.stdout)throw new TypeError(ERROR_STDOUT_TYPE);if(t.info&&"boolean"!=typeof t.info)throw new TypeError(ERROR_INFO_TYPE);if(t.rejected&&"boolean"!=typeof t.rejected)throw new TypeError(ERROR_REJECTED_TYPE);if(t.whitelistPatterns&&!Array.isArray(t.whitelistPatterns))throw new TypeError(ERROR_WHITELIST_PATTERNS_TYPE)}},{key:"purge",value:function(){var t=this.options,e=t.content,r=t.extractors,o=t.css,n=e.filter(function(t){return"string"==typeof t}),i=e.filter(function(t){return"object"===(void 0===t?"undefined":_typeof(t))}),a=this.extractFileSelector(n,r),s=this.extractRawSelector(i,r);return this.getCssContents(o,new Set([].concat(toConsumableArray(a),toConsumableArray(s))))}},{key:"getCssContents",value:function(t,e){var r=[],o=!0,n=!1,i=void 0;try{for(var a,s=t[Symbol.iterator]();!(o=(a=s.next()).done);o=!0){var l=a.value,u=null,c="";"string"==typeof l?(u=l,c=this.options.stdin?u:fs.readFileSync(u,"utf8")):c=l.raw,this.root=postcss.parse(c),this.getSelectorsCss(e),this.options.keyframes&&this.removeUnusedKeyframes(),r.push({file:u,css:this.root.toString()})}}catch(t){n=!0,i=t}finally{try{!o&&s.return&&s.return()}finally{if(n)throw i}}return r}},{key:"removeUnusedKeyframes",value:function(){var t=new Set;for(var e in this.root.walkDecls(/animation/,function(e){var r=!0,o=!1,n=void 0;try{for(var i,a=e.value.split(" ")[Symbol.iterator]();!(r=(i=a.next()).done);r=!0){var s=i.value;t.add(s)}}catch(t){o=!0,n=t}finally{try{!r&&a.return&&a.return()}finally{if(o)throw n}}}),this.atRules.keyframes){t.has(e)||this.atRules.keyframes[e].remove()}}},{key:"extractRawSelector",value:function(t,e){var r=new Set,o=!0,n=!1,i=void 0;try{for(var a,s=t[Symbol.iterator]();!(o=(a=s.next()).done);o=!0){var l=a.value,u=l.raw,c=l.extension,f=this.getFileExtractor("."+c,e);r=new Set([].concat(toConsumableArray(r),toConsumableArray(this.extractSelectors(u,f))))}}catch(t){n=!0,i=t}finally{try{!o&&s.return&&s.return()}finally{if(n)throw i}}return r}},{key:"extractFileSelector",value:function(t,e){var r=new Set,o=!0,n=!1,i=void 0;try{for(var a,s=t[Symbol.iterator]();!(o=(a=s.next()).done);o=!0){var l=a.value,u=[];fs.existsSync(l)?u.push(l):u=glob.sync(l);var c=!0,f=!1,y=void 0;try{for(var p,h=u[Symbol.iterator]();!(c=(p=h.next()).done);c=!0){var v=p.value,E=fs.readFileSync(v,"utf8"),R=this.getFileExtractor(v,e);r=new Set([].concat(toConsumableArray(r),toConsumableArray(this.extractSelectors(E,R))))}}catch(t){f=!0,y=t}finally{try{!c&&h.return&&h.return()}finally{if(f)throw y}}}}catch(t){n=!0,i=t}finally{try{!o&&s.return&&s.return()}finally{if(n)throw i}}return r}},{key:"getFileExtractor",value:function(t){var e=arguments.length>1&&void 0!==arguments[1]?arguments[1]:[];return e.length?e.find(function(e){return e.extensions.find(function(e){return t.endsWith(e)})}).extractor:!0===this.options.legacy?LegacyExtractor:DefaultExtractor}},{key:"extractSelectors",value:function(t,e){var r=new Set,o=e.extract(t);if(null===o)throw new Error(ERROR_EXTRACTER_FAILED);return o.forEach(function(t){r.add(t)}),r.delete(""),r}},{key:"getSelectorsCss",value:function(t){var e=this;this.root.walkRules(function(r){var o=r.prev();if(!e.isIgnoreAnnotation(o)){r.selector=selectorParser(function(r){r.walk(function(r){var o=[];if("selector"===r.type){if(r.parent&&":not"===r.parent.value&&"pseudo"===r.parent.type)return;var n=!0,i=!1,a=void 0;try{for(var s,l=r.nodes[Symbol.iterator]();!(n=(s=l.next()).done);n=!0){var u=s.value,c=u.type,f=u.value;SELECTOR_STANDARD_TYPES.includes(c)&&void 0!==f?o.push(f):"tag"!==c||/[+]|(even)|(odd)|^from$|^to$|^\d/.test(f)||o.push(f)}}catch(t){i=!0,a=t}finally{try{!n&&l.return&&l.return()}finally{if(i)throw a}}e.shouldKeepSelector(t,o)||r.remove()}})}).processSync(r.selector);var n=r.parent;"atrule"===n.type&&e.options.keyframes&&"keyframes"===n.name&&(e.atRules.keyframes[n.params]=n),r.selector||r.remove(),e.isRuleEmpty(n)&&n.remove()}})}},{key:"isIgnoreAnnotation",value:function(t){return!(!t||"comment"!==t.type)&&t.text.includes(IGNORE_ANNOTATION)}},{key:"isRuleEmpty",value:function(t){return!!("decl"===t.type&&!t.value||"rule"===t.type&&!t.selector||t.nodes&&!t.nodes.length||"atrule"===t.type&&(!t.nodes&&!t.params||!t.params&&!t.nodes.length))}},{key:"shouldKeepSelector",value:function(t,e){var r=!0,o=!1,n=void 0;try{for(var i,a=e[Symbol.iterator]();!(r=(i=a.next()).done);r=!0){var s=i.value;if(this.options.legacy){var l=s.split(/[^a-z]/g),u=!1,c=!0,f=!1,y=void 0;try{for(var p,h=l[Symbol.iterator]();!(c=(p=h.next()).done);c=!0){var v=p.value;if(v){if(!t.has(v))break;u=!0}}}catch(t){f=!0,y=t}finally{try{!c&&h.return&&h.return()}finally{if(f)throw y}}if(u)return!0;if(t.has(s)||CSS_WHITELIST.includes(s)||this.isSelectorWhitelisted(s))return!0}else{var E=s.replace(/\\/g,"");if(E.startsWith(":"))continue;if(!(t.has(E)||CSS_WHITELIST.includes(E)||this.isSelectorWhitelisted(E)))return!1}}}catch(t){o=!0,n=t}finally{try{!r&&a.return&&a.return()}finally{if(o)throw n}}return!this.options.legacy}},{key:"isSelectorWhitelisted",value:function(t){return!!(CSS_WHITELIST.includes(t)||this.options.whitelist&&this.options.whitelist.some(function(e){return e===t})||this.options.whitelistPatterns&&this.options.whitelistPatterns.some(function(e){return e.test(t)}))}}]),t}();export default Purgecss;
+import fs from"fs";import glob from"glob";import postcss from"postcss";import selectorParser from"postcss-selector-parser";function normalizeArray(e,t){for(var r=0,n=e.length-1;n>=0;n--){var o=e[n];"."===o?e.splice(n,1):".."===o?(e.splice(n,1),r++):r&&(e.splice(n,1),r--)}if(t)for(;r--;r)e.unshift("..");return e}var splitPathRe=/^(\/?|)([\s\S]*?)((?:\.{1,2}|[^\/]+?|)(\.[^.\/]*|))(?:[\/]*)$/,splitPath=function(e){return splitPathRe.exec(e).slice(1)};function resolve(){for(var e="",t=!1,r=arguments.length-1;r>=-1&&!t;r--){var n=r>=0?arguments[r]:"/";if("string"!=typeof n)throw new TypeError("Arguments to path.resolve must be strings");n&&(e=n+"/"+e,t="/"===n.charAt(0))}return e=normalizeArray(filter(e.split("/"),function(e){return!!e}),!t).join("/"),(t?"/":"")+e||"."}function normalize(e){var t=isAbsolute(e),r="/"===substr(e,-1);return(e=normalizeArray(filter(e.split("/"),function(e){return!!e}),!t).join("/"))||t||(e="."),e&&r&&(e+="/"),(t?"/":"")+e}function isAbsolute(e){return"/"===e.charAt(0)}function join(){return normalize(filter(Array.prototype.slice.call(arguments,0),function(e,t){if("string"!=typeof e)throw new TypeError("Arguments to path.join must be strings");return e}).join("/"))}function relative(e,t){function r(e){for(var t=0;t<e.length&&""===e[t];t++);for(var r=e.length-1;r>=0&&""===e[r];r--);return t>r?[]:e.slice(t,r-t+1)}e=resolve(e).substr(1),t=resolve(t).substr(1);for(var n=r(e.split("/")),o=r(t.split("/")),i=Math.min(n.length,o.length),a=i,s=0;s<i;s++)if(n[s]!==o[s]){a=s;break}var l=[];for(s=a;s<n.length;s++)l.push("..");return(l=l.concat(o.slice(a))).join("/")}var sep="/",delimiter=":";function dirname(e){var t=splitPath(e),r=t[0],n=t[1];return r||n?(n&&(n=n.substr(0,n.length-1)),r+n):"."}function basename(e,t){var r=splitPath(e)[2];return t&&r.substr(-1*t.length)===t&&(r=r.substr(0,r.length-t.length)),r}function extname(e){return splitPath(e)[3]}var path={extname:extname,basename:basename,dirname:dirname,sep:sep,delimiter:delimiter,relative:relative,join:join,isAbsolute:isAbsolute,normalize:normalize,resolve:resolve};function filter(e,t){if(e.filter)return e.filter(t);for(var r=[],n=0;n<e.length;n++)t(e[n],n,e)&&r.push(e[n]);return r}var substr="b"==="ab".substr(-1)?function(e,t,r){return e.substr(t,r)}:function(e,t,r){return t<0&&(t=e.length+t),e.substr(t,r)},defaultOptions={css:[],content:[],extractors:[],whitelist:[],output:void 0,stdout:!1,info:!1,rejected:!1,legacy:!1,keyframes:!1,fontFace:!1},IGNORE_ANNOTATION="purgecss ignore",CONFIG_FILENAME="purgecss.config.js",ERROR_CONFIG_FILE_LOADING="Error loading the config file",ERROR_MISSING_CONTENT="No content provided.",ERROR_MISSING_CSS="No css provided.",ERROR_EXTRACTER_FAILED="The extractor has failed to extract the selectors.",ERROR_OPTIONS_TYPE="Error Type Options: expected an object",ERROR_OUTPUT_TYPE="Error Type option output: expected a string",ERROR_EXTRACTERS_TYPE="Error Type option extractors: expected an array",ERROR_WHITELIST_TYPE="Error Type option whitelist: expected an array",ERROR_WHITELIST_PATTERNS_TYPE="Error Type option whitelistPatterns: expected an array",ERROR_STDOUT_TYPE="Error Type option stdout: expected a boolean",ERROR_INFO_TYPE="Error Type option info: expected a boolean",ERROR_REJECTED_TYPE="Error Type option rejected: expected a boolean",CSS_WHITELIST=["*","::-webkit-scrollbar","::selection",":root","::before","::after"],SELECTOR_STANDARD_TYPES=["class","id","universal","pseudo"],_typeof="function"==typeof Symbol&&"symbol"==typeof Symbol.iterator?function(e){return typeof e}:function(e){return e&&"function"==typeof Symbol&&e.constructor===Symbol&&e!==Symbol.prototype?"symbol":typeof e},classCallCheck=function(e,t){if(!(e instanceof t))throw new TypeError("Cannot call a class as a function")},createClass=function(){function e(e,t){for(var r=0;r<t.length;r++){var n=t[r];n.enumerable=n.enumerable||!1,n.configurable=!0,"value"in n&&(n.writable=!0),Object.defineProperty(e,n.key,n)}}return function(t,r,n){return r&&e(t.prototype,r),n&&e(t,n),t}}(),toConsumableArray=function(e){if(Array.isArray(e)){for(var t=0,r=Array(e.length);t<e.length;t++)r[t]=e[t];return r}return Array.from(e)},DefaultExtractor=function(){function e(){classCallCheck(this,e)}return createClass(e,null,[{key:"extract",value:function(e){return e.match(/[A-Za-z0-9_-]+/g)}}]),e}(),LegacyExtractor=function(){function e(){classCallCheck(this,e)}return createClass(e,null,[{key:"extract",value:function(e){return e.split(/[^a-z]/g)}}]),e}(),Purgecss=function(){function e(t){classCallCheck(this,e),this.atRules={keyframes:[],fontFace:[]},this.usedAnimations=new Set,this.usedFontFaces=new Set,this.selectorsRemoved=new Set,"string"!=typeof t&&void 0!==t||(t=this.loadConfigFile(t)),this.checkOptions(t),this.options=Object.assign(defaultOptions,t)}return createClass(e,[{key:"loadConfigFile",value:function(e){var t=void 0===e?CONFIG_FILENAME:e,r=void 0;try{var n=path.resolve(process.cwd(),t);r=require(n)}catch(e){throw new Error(ERROR_CONFIG_FILE_LOADING+e.message)}return r}},{key:"checkOptions",value:function(e){if("object"!==(void 0===e?"undefined":_typeof(e)))throw new TypeError(ERROR_OPTIONS_TYPE);if(!e.content||!e.content.length)throw new Error(ERROR_MISSING_CONTENT);if(!e.css||!e.css.length)throw new Error(ERROR_MISSING_CSS);if(e.output&&"string"!=typeof e.output)throw new TypeError(ERROR_OUTPUT_TYPE);if(e.extractors&&!Array.isArray(e.extractors))throw new TypeError(ERROR_EXTRACTERS_TYPE);if(e.whitelist&&!Array.isArray(e.whitelist))throw new TypeError(ERROR_WHITELIST_TYPE);if(e.stdout&&"boolean"!=typeof e.stdout)throw new TypeError(ERROR_STDOUT_TYPE);if(e.info&&"boolean"!=typeof e.info)throw new TypeError(ERROR_INFO_TYPE);if(e.rejected&&"boolean"!=typeof e.rejected)throw new TypeError(ERROR_REJECTED_TYPE);if(e.whitelistPatterns&&!Array.isArray(e.whitelistPatterns))throw new TypeError(ERROR_WHITELIST_PATTERNS_TYPE)}},{key:"purge",value:function(){var e=this.options,t=e.content,r=e.extractors,n=e.css,o=t.filter(function(e){return"string"==typeof e}),i=t.filter(function(e){return"object"===(void 0===e?"undefined":_typeof(e))}),a=this.extractFileSelector(o,r),s=this.extractRawSelector(i,r);return this.getCssContents(n,new Set([].concat(toConsumableArray(a),toConsumableArray(s))))}},{key:"getCssContents",value:function(e,t){var r=[],n=!0,o=!1,i=void 0;try{for(var a,s=e[Symbol.iterator]();!(n=(a=s.next()).done);n=!0){var l=a.value,u=null,c="";"string"==typeof l?(u=l,c=this.options.stdin?u:fs.readFileSync(u,"utf8")):c=l.raw,this.root=postcss.parse(c),this.getSelectorsCss(t),this.options.keyframes&&this.removeUnusedKeyframes(),this.options.fontFace&&this.removeUnusedFontFaces(),r.push({file:u,css:this.root.toString()})}}catch(e){o=!0,i=e}finally{try{!n&&s.return&&s.return()}finally{if(o)throw i}}return r}},{key:"removeUnusedKeyframes",value:function(){var e=!0,t=!1,r=void 0;try{for(var n,o=this.atRules.keyframes[Symbol.iterator]();!(e=(n=o.next()).done);e=!0){var i=n.value,a=i.params;this.usedAnimations.has(a)||i.remove()}}catch(e){t=!0,r=e}finally{try{!e&&o.return&&o.return()}finally{if(t)throw r}}}},{key:"removeUnusedFontFaces",value:function(){var e=!0,t=!1,r=void 0;try{for(var n,o=this.atRules.fontFace[Symbol.iterator]();!(e=(n=o.next()).done);e=!0){var i=n.value,a=i.node,s=i.name;this.usedFontFaces.has(s)||a.remove()}}catch(e){t=!0,r=e}finally{try{!e&&o.return&&o.return()}finally{if(t)throw r}}}},{key:"extractRawSelector",value:function(e,t){var r=new Set,n=!0,o=!1,i=void 0;try{for(var a,s=e[Symbol.iterator]();!(n=(a=s.next()).done);n=!0){var l=a.value,u=l.raw,c=l.extension,f=this.getFileExtractor("."+c,t);r=new Set([].concat(toConsumableArray(r),toConsumableArray(this.extractSelectors(u,f))))}}catch(e){o=!0,i=e}finally{try{!n&&s.return&&s.return()}finally{if(o)throw i}}return r}},{key:"extractFileSelector",value:function(e,t){var r=new Set,n=!0,o=!1,i=void 0;try{for(var a,s=e[Symbol.iterator]();!(n=(a=s.next()).done);n=!0){var l=a.value,u=[];fs.existsSync(l)?u.push(l):u=glob.sync(l);var c=!0,f=!1,y=void 0;try{for(var h,p=u[Symbol.iterator]();!(c=(h=p.next()).done);c=!0){var v=h.value,d=fs.readFileSync(v,"utf8"),E=this.getFileExtractor(v,t);r=new Set([].concat(toConsumableArray(r),toConsumableArray(this.extractSelectors(d,E))))}}catch(e){f=!0,y=e}finally{try{!c&&p.return&&p.return()}finally{if(f)throw y}}}}catch(e){o=!0,i=e}finally{try{!n&&s.return&&s.return()}finally{if(o)throw i}}return r}},{key:"getFileExtractor",value:function(e){var t=arguments.length>1&&void 0!==arguments[1]?arguments[1]:[];return t.length?t.find(function(t){return t.extensions.find(function(t){return e.endsWith(t)})}).extractor:!0===this.options.legacy?LegacyExtractor:DefaultExtractor}},{key:"extractSelectors",value:function(e,t){var r=new Set,n=t.extract(e);if(null===n)throw new Error(ERROR_EXTRACTER_FAILED);return n.forEach(function(e){r.add(e)}),r.delete(""),r}},{key:"getSelectorsCss",value:function(e){var t=this;this.root.walk(function(r){return"rule"===r.type?t.evaluateRule(r,e):"atrule"===r.type?t.evaluateAtRule(r):void 0})}},{key:"evaluateRule",value:function(e,t){var r=this,n=e.prev();if(!this.isIgnoreAnnotation(n)){var o=!0;if(e.selector=selectorParser(function(e){e.walk(function(e){var n=[];if("selector"===e.type){if(e.parent&&":not"===e.parent.value&&"pseudo"===e.parent.type)return;var i=!0,a=!1,s=void 0;try{for(var l,u=e.nodes[Symbol.iterator]();!(i=(l=u.next()).done);i=!0){var c=l.value,f=c.type,y=c.value;SELECTOR_STANDARD_TYPES.includes(f)&&void 0!==y?n.push(y):"tag"!==f||/[+]|(even)|(odd)|^from$|^to$|^\d/.test(y)||n.push(y)}}catch(e){a=!0,s=e}finally{try{!i&&u.return&&u.return()}finally{if(a)throw s}}(o=r.shouldKeepSelector(t,n))||e.remove()}})}).processSync(e.selector),o){var i=!0,a=!1,s=void 0;try{for(var l,u=e.nodes[Symbol.iterator]();!(i=(l=u.next()).done);i=!0){var c=l.value,f=c.prop,y=c.value;if(this.options.keyframes&&("animation"===f||"animation-name"===f)){var h=!0,p=!1,v=void 0;try{for(var d,E=y.split(" ")[Symbol.iterator]();!(h=(d=E.next()).done);h=!0){var R=d.value;this.usedAnimations.add(R)}}catch(e){p=!0,v=e}finally{try{!h&&E.return&&E.return()}finally{if(p)throw v}}}this.options.fontFace&&"font-family"===f&&this.usedFontFaces.add(y)}}catch(e){a=!0,s=e}finally{try{!i&&u.return&&u.return()}finally{if(a)throw s}}}var m=e.parent;e.selector||e.remove(),this.isRuleEmpty(m)&&m.remove()}}},{key:"evaluateAtRule",value:function(e){if(this.options.keyframes&&e.name.endsWith("keyframes"))this.atRules.keyframes.push(e);else if(this.options.fontFace&&"font-face"===e.name){var t=!0,r=!1,n=void 0;try{for(var o,i=e.nodes[Symbol.iterator]();!(t=(o=i.next()).done);t=!0){var a=o.value,s=a.prop,l=a.value;"font-family"===s&&this.atRules.fontFace.push({name:l,node:e})}}catch(e){r=!0,n=e}finally{try{!t&&i.return&&i.return()}finally{if(r)throw n}}}else;}},{key:"isIgnoreAnnotation",value:function(e){return!(!e||"comment"!==e.type)&&e.text.includes(IGNORE_ANNOTATION)}},{key:"isRuleEmpty",value:function(e){return!!("decl"===e.type&&!e.value||"rule"===e.type&&!e.selector||e.nodes&&!e.nodes.length||"atrule"===e.type&&(!e.nodes&&!e.params||!e.params&&!e.nodes.length))}},{key:"shouldKeepSelector",value:function(e,t){var r=!0,n=!1,o=void 0;try{for(var i,a=t[Symbol.iterator]();!(r=(i=a.next()).done);r=!0){var s=i.value;if(this.options.legacy){var l=s.split(/[^a-z]/g),u=!1,c=!0,f=!1,y=void 0;try{for(var h,p=l[Symbol.iterator]();!(c=(h=p.next()).done);c=!0){var v=h.value;if(v){if(!e.has(v))break;u=!0}}}catch(e){f=!0,y=e}finally{try{!c&&p.return&&p.return()}finally{if(f)throw y}}if(u)return!0;if(e.has(s)||CSS_WHITELIST.includes(s)||this.isSelectorWhitelisted(s))return!0}else{var d=s.replace(/\\/g,"");if(d.startsWith(":"))continue;if(!(e.has(d)||CSS_WHITELIST.includes(d)||this.isSelectorWhitelisted(d)))return!1}}}catch(e){n=!0,o=e}finally{try{!r&&a.return&&a.return()}finally{if(n)throw o}}return!this.options.legacy}},{key:"isSelectorWhitelisted",value:function(e){return!!(CSS_WHITELIST.includes(e)||this.options.whitelist&&this.options.whitelist.some(function(t){return t===e})||this.options.whitelistPatterns&&this.options.whitelistPatterns.some(function(t){return t.test(e)}))}}]),e}();export default Purgecss;
diff --git a/lib/purgecss.js b/lib/purgecss.js
index cc7bd43f..abc70c7a 100644
--- a/lib/purgecss.js
+++ b/lib/purgecss.js
@@ -1 +1 @@
-"use strict";function _interopDefault(e){return e&&"object"==typeof e&&"default"in e?e.default:e}var fs=_interopDefault(require("fs")),glob=_interopDefault(require("glob")),postcss=_interopDefault(require("postcss")),selectorParser=_interopDefault(require("postcss-selector-parser"));function normalizeArray(e,t){for(var r=0,n=e.length-1;n>=0;n--){var o=e[n];"."===o?e.splice(n,1):".."===o?(e.splice(n,1),r++):r&&(e.splice(n,1),r--)}if(t)for(;r--;r)e.unshift("..");return e}var splitPathRe=/^(\/?|)([\s\S]*?)((?:\.{1,2}|[^\/]+?|)(\.[^.\/]*|))(?:[\/]*)$/,splitPath=function(e){return splitPathRe.exec(e).slice(1)};function resolve(){for(var e="",t=!1,r=arguments.length-1;r>=-1&&!t;r--){var n=r>=0?arguments[r]:"/";if("string"!=typeof n)throw new TypeError("Arguments to path.resolve must be strings");n&&(e=n+"/"+e,t="/"===n.charAt(0))}return e=normalizeArray(filter(e.split("/"),function(e){return!!e}),!t).join("/"),(t?"/":"")+e||"."}function normalize(e){var t=isAbsolute(e),r="/"===substr(e,-1);return(e=normalizeArray(filter(e.split("/"),function(e){return!!e}),!t).join("/"))||t||(e="."),e&&r&&(e+="/"),(t?"/":"")+e}function isAbsolute(e){return"/"===e.charAt(0)}function join(){return normalize(filter(Array.prototype.slice.call(arguments,0),function(e,t){if("string"!=typeof e)throw new TypeError("Arguments to path.join must be strings");return e}).join("/"))}function relative(e,t){function r(e){for(var t=0;t<e.length&&""===e[t];t++);for(var r=e.length-1;r>=0&&""===e[r];r--);return t>r?[]:e.slice(t,r-t+1)}e=resolve(e).substr(1),t=resolve(t).substr(1);for(var n=r(e.split("/")),o=r(t.split("/")),i=Math.min(n.length,o.length),a=i,s=0;s<i;s++)if(n[s]!==o[s]){a=s;break}var l=[];for(s=a;s<n.length;s++)l.push("..");return(l=l.concat(o.slice(a))).join("/")}var sep="/",delimiter=":";function dirname(e){var t=splitPath(e),r=t[0],n=t[1];return r||n?(n&&(n=n.substr(0,n.length-1)),r+n):"."}function basename(e,t){var r=splitPath(e)[2];return t&&r.substr(-1*t.length)===t&&(r=r.substr(0,r.length-t.length)),r}function extname(e){return splitPath(e)[3]}var path={extname:extname,basename:basename,dirname:dirname,sep:sep,delimiter:delimiter,relative:relative,join:join,isAbsolute:isAbsolute,normalize:normalize,resolve:resolve};function filter(e,t){if(e.filter)return e.filter(t);for(var r=[],n=0;n<e.length;n++)t(e[n],n,e)&&r.push(e[n]);return r}var substr="b"==="ab".substr(-1)?function(e,t,r){return e.substr(t,r)}:function(e,t,r){return t<0&&(t=e.length+t),e.substr(t,r)},defaultOptions={css:[],content:[],extractors:[],whitelist:[],output:void 0,stdout:!1,info:!1,rejected:!1,legacy:!1,keyframes:!1},IGNORE_ANNOTATION="purgecss ignore",CONFIG_FILENAME="purgecss.config.js",ERROR_CONFIG_FILE_LOADING="Error loading the config file",ERROR_MISSING_CONTENT="No content provided.",ERROR_MISSING_CSS="No css provided.",ERROR_EXTRACTER_FAILED="The extractor has failed to extract the selectors.",ERROR_OPTIONS_TYPE="Error Type Options: expected an object",ERROR_OUTPUT_TYPE="Error Type option output: expected a string",ERROR_EXTRACTERS_TYPE="Error Type option extractors: expected an array",ERROR_WHITELIST_TYPE="Error Type option whitelist: expected an array",ERROR_WHITELIST_PATTERNS_TYPE="Error Type option whitelistPatterns: expected an array",ERROR_STDOUT_TYPE="Error Type option stdout: expected a boolean",ERROR_INFO_TYPE="Error Type option info: expected a boolean",ERROR_REJECTED_TYPE="Error Type option rejected: expected a boolean",CSS_WHITELIST=["*","::-webkit-scrollbar","::selection",":root","::before","::after"],SELECTOR_STANDARD_TYPES=["class","id","universal","pseudo"],_typeof="function"==typeof Symbol&&"symbol"==typeof Symbol.iterator?function(e){return typeof e}:function(e){return e&&"function"==typeof Symbol&&e.constructor===Symbol&&e!==Symbol.prototype?"symbol":typeof e},classCallCheck=function(e,t){if(!(e instanceof t))throw new TypeError("Cannot call a class as a function")},createClass=function(){function e(e,t){for(var r=0;r<t.length;r++){var n=t[r];n.enumerable=n.enumerable||!1,n.configurable=!0,"value"in n&&(n.writable=!0),Object.defineProperty(e,n.key,n)}}return function(t,r,n){return r&&e(t.prototype,r),n&&e(t,n),t}}(),toConsumableArray=function(e){if(Array.isArray(e)){for(var t=0,r=Array(e.length);t<e.length;t++)r[t]=e[t];return r}return Array.from(e)},DefaultExtractor=function(){function e(){classCallCheck(this,e)}return createClass(e,null,[{key:"extract",value:function(e){return e.match(/[A-Za-z0-9_-]+/g)}}]),e}(),LegacyExtractor=function(){function e(){classCallCheck(this,e)}return createClass(e,null,[{key:"extract",value:function(e){return e.split(/[^a-z]/g)}}]),e}(),Purgecss=function(){function e(t){classCallCheck(this,e),this.atRules={keyframes:{}},"string"!=typeof t&&void 0!==t||(t=this.loadConfigFile(t)),this.checkOptions(t),this.options=Object.assign(defaultOptions,t)}return createClass(e,[{key:"loadConfigFile",value:function(e){var t=void 0===e?CONFIG_FILENAME:e,r=void 0;try{var n=path.resolve(process.cwd(),t);r=require(n)}catch(e){throw new Error(ERROR_CONFIG_FILE_LOADING+e.message)}return r}},{key:"checkOptions",value:function(e){if("object"!==(void 0===e?"undefined":_typeof(e)))throw new TypeError(ERROR_OPTIONS_TYPE);if(!e.content||!e.content.length)throw new Error(ERROR_MISSING_CONTENT);if(!e.css||!e.css.length)throw new Error(ERROR_MISSING_CSS);if(e.output&&"string"!=typeof e.output)throw new TypeError(ERROR_OUTPUT_TYPE);if(e.extractors&&!Array.isArray(e.extractors))throw new TypeError(ERROR_EXTRACTERS_TYPE);if(e.whitelist&&!Array.isArray(e.whitelist))throw new TypeError(ERROR_WHITELIST_TYPE);if(e.stdout&&"boolean"!=typeof e.stdout)throw new TypeError(ERROR_STDOUT_TYPE);if(e.info&&"boolean"!=typeof e.info)throw new TypeError(ERROR_INFO_TYPE);if(e.rejected&&"boolean"!=typeof e.rejected)throw new TypeError(ERROR_REJECTED_TYPE);if(e.whitelistPatterns&&!Array.isArray(e.whitelistPatterns))throw new TypeError(ERROR_WHITELIST_PATTERNS_TYPE)}},{key:"purge",value:function(){var e=this.options,t=e.content,r=e.extractors,n=e.css,o=t.filter(function(e){return"string"==typeof e}),i=t.filter(function(e){return"object"===(void 0===e?"undefined":_typeof(e))}),a=this.extractFileSelector(o,r),s=this.extractRawSelector(i,r);return this.getCssContents(n,new Set([].concat(toConsumableArray(a),toConsumableArray(s))))}},{key:"getCssContents",value:function(e,t){var r=[],n=!0,o=!1,i=void 0;try{for(var a,s=e[Symbol.iterator]();!(n=(a=s.next()).done);n=!0){var l=a.value,u=null,c="";"string"==typeof l?(u=l,c=this.options.stdin?u:fs.readFileSync(u,"utf8")):c=l.raw,this.root=postcss.parse(c),this.getSelectorsCss(t),this.options.keyframes&&this.removeUnusedKeyframes(),r.push({file:u,css:this.root.toString()})}}catch(e){o=!0,i=e}finally{try{!n&&s.return&&s.return()}finally{if(o)throw i}}return r}},{key:"removeUnusedKeyframes",value:function(){var e=new Set;for(var t in this.root.walkDecls(/animation/,function(t){var r=!0,n=!1,o=void 0;try{for(var i,a=t.value.split(" ")[Symbol.iterator]();!(r=(i=a.next()).done);r=!0){var s=i.value;e.add(s)}}catch(e){n=!0,o=e}finally{try{!r&&a.return&&a.return()}finally{if(n)throw o}}}),this.atRules.keyframes){e.has(t)||this.atRules.keyframes[t].remove()}}},{key:"extractRawSelector",value:function(e,t){var r=new Set,n=!0,o=!1,i=void 0;try{for(var a,s=e[Symbol.iterator]();!(n=(a=s.next()).done);n=!0){var l=a.value,u=l.raw,c=l.extension,f=this.getFileExtractor("."+c,t);r=new Set([].concat(toConsumableArray(r),toConsumableArray(this.extractSelectors(u,f))))}}catch(e){o=!0,i=e}finally{try{!n&&s.return&&s.return()}finally{if(o)throw i}}return r}},{key:"extractFileSelector",value:function(e,t){var r=new Set,n=!0,o=!1,i=void 0;try{for(var a,s=e[Symbol.iterator]();!(n=(a=s.next()).done);n=!0){var l=a.value,u=[];fs.existsSync(l)?u.push(l):u=glob.sync(l);var c=!0,f=!1,y=void 0;try{for(var p,h=u[Symbol.iterator]();!(c=(p=h.next()).done);c=!0){var v=p.value,E=fs.readFileSync(v,"utf8"),R=this.getFileExtractor(v,t);r=new Set([].concat(toConsumableArray(r),toConsumableArray(this.extractSelectors(E,R))))}}catch(e){f=!0,y=e}finally{try{!c&&h.return&&h.return()}finally{if(f)throw y}}}}catch(e){o=!0,i=e}finally{try{!n&&s.return&&s.return()}finally{if(o)throw i}}return r}},{key:"getFileExtractor",value:function(e){var t=arguments.length>1&&void 0!==arguments[1]?arguments[1]:[];return t.length?t.find(function(t){return t.extensions.find(function(t){return e.endsWith(t)})}).extractor:!0===this.options.legacy?LegacyExtractor:DefaultExtractor}},{key:"extractSelectors",value:function(e,t){var r=new Set,n=t.extract(e);if(null===n)throw new Error(ERROR_EXTRACTER_FAILED);return n.forEach(function(e){r.add(e)}),r.delete(""),r}},{key:"getSelectorsCss",value:function(e){var t=this;this.root.walkRules(function(r){var n=r.prev();if(!t.isIgnoreAnnotation(n)){r.selector=selectorParser(function(r){r.walk(function(r){var n=[];if("selector"===r.type){if(r.parent&&":not"===r.parent.value&&"pseudo"===r.parent.type)return;var o=!0,i=!1,a=void 0;try{for(var s,l=r.nodes[Symbol.iterator]();!(o=(s=l.next()).done);o=!0){var u=s.value,c=u.type,f=u.value;SELECTOR_STANDARD_TYPES.includes(c)&&void 0!==f?n.push(f):"tag"!==c||/[+]|(even)|(odd)|^from$|^to$|^\d/.test(f)||n.push(f)}}catch(e){i=!0,a=e}finally{try{!o&&l.return&&l.return()}finally{if(i)throw a}}t.shouldKeepSelector(e,n)||r.remove()}})}).processSync(r.selector);var o=r.parent;"atrule"===o.type&&t.options.keyframes&&"keyframes"===o.name&&(t.atRules.keyframes[o.params]=o),r.selector||r.remove(),t.isRuleEmpty(o)&&o.remove()}})}},{key:"isIgnoreAnnotation",value:function(e){return!(!e||"comment"!==e.type)&&e.text.includes(IGNORE_ANNOTATION)}},{key:"isRuleEmpty",value:function(e){return!!("decl"===e.type&&!e.value||"rule"===e.type&&!e.selector||e.nodes&&!e.nodes.length||"atrule"===e.type&&(!e.nodes&&!e.params||!e.params&&!e.nodes.length))}},{key:"shouldKeepSelector",value:function(e,t){var r=!0,n=!1,o=void 0;try{for(var i,a=t[Symbol.iterator]();!(r=(i=a.next()).done);r=!0){var s=i.value;if(this.options.legacy){var l=s.split(/[^a-z]/g),u=!1,c=!0,f=!1,y=void 0;try{for(var p,h=l[Symbol.iterator]();!(c=(p=h.next()).done);c=!0){var v=p.value;if(v){if(!e.has(v))break;u=!0}}}catch(e){f=!0,y=e}finally{try{!c&&h.return&&h.return()}finally{if(f)throw y}}if(u)return!0;if(e.has(s)||CSS_WHITELIST.includes(s)||this.isSelectorWhitelisted(s))return!0}else{var E=s.replace(/\\/g,"");if(E.startsWith(":"))continue;if(!(e.has(E)||CSS_WHITELIST.includes(E)||this.isSelectorWhitelisted(E)))return!1}}}catch(e){n=!0,o=e}finally{try{!r&&a.return&&a.return()}finally{if(n)throw o}}return!this.options.legacy}},{key:"isSelectorWhitelisted",value:function(e){return!!(CSS_WHITELIST.includes(e)||this.options.whitelist&&this.options.whitelist.some(function(t){return t===e})||this.options.whitelistPatterns&&this.options.whitelistPatterns.some(function(t){return t.test(e)}))}}]),e}();module.exports=Purgecss;
+"use strict";function _interopDefault(e){return e&&"object"==typeof e&&"default"in e?e.default:e}var fs=_interopDefault(require("fs")),glob=_interopDefault(require("glob")),postcss=_interopDefault(require("postcss")),selectorParser=_interopDefault(require("postcss-selector-parser"));function normalizeArray(e,t){for(var r=0,n=e.length-1;n>=0;n--){var o=e[n];"."===o?e.splice(n,1):".."===o?(e.splice(n,1),r++):r&&(e.splice(n,1),r--)}if(t)for(;r--;r)e.unshift("..");return e}var splitPathRe=/^(\/?|)([\s\S]*?)((?:\.{1,2}|[^\/]+?|)(\.[^.\/]*|))(?:[\/]*)$/,splitPath=function(e){return splitPathRe.exec(e).slice(1)};function resolve(){for(var e="",t=!1,r=arguments.length-1;r>=-1&&!t;r--){var n=r>=0?arguments[r]:"/";if("string"!=typeof n)throw new TypeError("Arguments to path.resolve must be strings");n&&(e=n+"/"+e,t="/"===n.charAt(0))}return e=normalizeArray(filter(e.split("/"),function(e){return!!e}),!t).join("/"),(t?"/":"")+e||"."}function normalize(e){var t=isAbsolute(e),r="/"===substr(e,-1);return(e=normalizeArray(filter(e.split("/"),function(e){return!!e}),!t).join("/"))||t||(e="."),e&&r&&(e+="/"),(t?"/":"")+e}function isAbsolute(e){return"/"===e.charAt(0)}function join(){return normalize(filter(Array.prototype.slice.call(arguments,0),function(e,t){if("string"!=typeof e)throw new TypeError("Arguments to path.join must be strings");return e}).join("/"))}function relative(e,t){function r(e){for(var t=0;t<e.length&&""===e[t];t++);for(var r=e.length-1;r>=0&&""===e[r];r--);return t>r?[]:e.slice(t,r-t+1)}e=resolve(e).substr(1),t=resolve(t).substr(1);for(var n=r(e.split("/")),o=r(t.split("/")),i=Math.min(n.length,o.length),a=i,s=0;s<i;s++)if(n[s]!==o[s]){a=s;break}var l=[];for(s=a;s<n.length;s++)l.push("..");return(l=l.concat(o.slice(a))).join("/")}var sep="/",delimiter=":";function dirname(e){var t=splitPath(e),r=t[0],n=t[1];return r||n?(n&&(n=n.substr(0,n.length-1)),r+n):"."}function basename(e,t){var r=splitPath(e)[2];return t&&r.substr(-1*t.length)===t&&(r=r.substr(0,r.length-t.length)),r}function extname(e){return splitPath(e)[3]}var path={extname:extname,basename:basename,dirname:dirname,sep:sep,delimiter:delimiter,relative:relative,join:join,isAbsolute:isAbsolute,normalize:normalize,resolve:resolve};function filter(e,t){if(e.filter)return e.filter(t);for(var r=[],n=0;n<e.length;n++)t(e[n],n,e)&&r.push(e[n]);return r}var substr="b"==="ab".substr(-1)?function(e,t,r){return e.substr(t,r)}:function(e,t,r){return t<0&&(t=e.length+t),e.substr(t,r)},defaultOptions={css:[],content:[],extractors:[],whitelist:[],output:void 0,stdout:!1,info:!1,rejected:!1,legacy:!1,keyframes:!1,fontFace:!1},IGNORE_ANNOTATION="purgecss ignore",CONFIG_FILENAME="purgecss.config.js",ERROR_CONFIG_FILE_LOADING="Error loading the config file",ERROR_MISSING_CONTENT="No content provided.",ERROR_MISSING_CSS="No css provided.",ERROR_EXTRACTER_FAILED="The extractor has failed to extract the selectors.",ERROR_OPTIONS_TYPE="Error Type Options: expected an object",ERROR_OUTPUT_TYPE="Error Type option output: expected a string",ERROR_EXTRACTERS_TYPE="Error Type option extractors: expected an array",ERROR_WHITELIST_TYPE="Error Type option whitelist: expected an array",ERROR_WHITELIST_PATTERNS_TYPE="Error Type option whitelistPatterns: expected an array",ERROR_STDOUT_TYPE="Error Type option stdout: expected a boolean",ERROR_INFO_TYPE="Error Type option info: expected a boolean",ERROR_REJECTED_TYPE="Error Type option rejected: expected a boolean",CSS_WHITELIST=["*","::-webkit-scrollbar","::selection",":root","::before","::after"],SELECTOR_STANDARD_TYPES=["class","id","universal","pseudo"],_typeof="function"==typeof Symbol&&"symbol"==typeof Symbol.iterator?function(e){return typeof e}:function(e){return e&&"function"==typeof Symbol&&e.constructor===Symbol&&e!==Symbol.prototype?"symbol":typeof e},classCallCheck=function(e,t){if(!(e instanceof t))throw new TypeError("Cannot call a class as a function")},createClass=function(){function e(e,t){for(var r=0;r<t.length;r++){var n=t[r];n.enumerable=n.enumerable||!1,n.configurable=!0,"value"in n&&(n.writable=!0),Object.defineProperty(e,n.key,n)}}return function(t,r,n){return r&&e(t.prototype,r),n&&e(t,n),t}}(),toConsumableArray=function(e){if(Array.isArray(e)){for(var t=0,r=Array(e.length);t<e.length;t++)r[t]=e[t];return r}return Array.from(e)},DefaultExtractor=function(){function e(){classCallCheck(this,e)}return createClass(e,null,[{key:"extract",value:function(e){return e.match(/[A-Za-z0-9_-]+/g)}}]),e}(),LegacyExtractor=function(){function e(){classCallCheck(this,e)}return createClass(e,null,[{key:"extract",value:function(e){return e.split(/[^a-z]/g)}}]),e}(),Purgecss=function(){function e(t){classCallCheck(this,e),this.atRules={keyframes:[],fontFace:[]},this.usedAnimations=new Set,this.usedFontFaces=new Set,this.selectorsRemoved=new Set,"string"!=typeof t&&void 0!==t||(t=this.loadConfigFile(t)),this.checkOptions(t),this.options=Object.assign(defaultOptions,t)}return createClass(e,[{key:"loadConfigFile",value:function(e){var t=void 0===e?CONFIG_FILENAME:e,r=void 0;try{var n=path.resolve(process.cwd(),t);r=require(n)}catch(e){throw new Error(ERROR_CONFIG_FILE_LOADING+e.message)}return r}},{key:"checkOptions",value:function(e){if("object"!==(void 0===e?"undefined":_typeof(e)))throw new TypeError(ERROR_OPTIONS_TYPE);if(!e.content||!e.content.length)throw new Error(ERROR_MISSING_CONTENT);if(!e.css||!e.css.length)throw new Error(ERROR_MISSING_CSS);if(e.output&&"string"!=typeof e.output)throw new TypeError(ERROR_OUTPUT_TYPE);if(e.extractors&&!Array.isArray(e.extractors))throw new TypeError(ERROR_EXTRACTERS_TYPE);if(e.whitelist&&!Array.isArray(e.whitelist))throw new TypeError(ERROR_WHITELIST_TYPE);if(e.stdout&&"boolean"!=typeof e.stdout)throw new TypeError(ERROR_STDOUT_TYPE);if(e.info&&"boolean"!=typeof e.info)throw new TypeError(ERROR_INFO_TYPE);if(e.rejected&&"boolean"!=typeof e.rejected)throw new TypeError(ERROR_REJECTED_TYPE);if(e.whitelistPatterns&&!Array.isArray(e.whitelistPatterns))throw new TypeError(ERROR_WHITELIST_PATTERNS_TYPE)}},{key:"purge",value:function(){var e=this.options,t=e.content,r=e.extractors,n=e.css,o=t.filter(function(e){return"string"==typeof e}),i=t.filter(function(e){return"object"===(void 0===e?"undefined":_typeof(e))}),a=this.extractFileSelector(o,r),s=this.extractRawSelector(i,r);return this.getCssContents(n,new Set([].concat(toConsumableArray(a),toConsumableArray(s))))}},{key:"getCssContents",value:function(e,t){var r=[],n=!0,o=!1,i=void 0;try{for(var a,s=e[Symbol.iterator]();!(n=(a=s.next()).done);n=!0){var l=a.value,u=null,c="";"string"==typeof l?(u=l,c=this.options.stdin?u:fs.readFileSync(u,"utf8")):c=l.raw,this.root=postcss.parse(c),this.getSelectorsCss(t),this.options.keyframes&&this.removeUnusedKeyframes(),this.options.fontFace&&this.removeUnusedFontFaces(),r.push({file:u,css:this.root.toString()})}}catch(e){o=!0,i=e}finally{try{!n&&s.return&&s.return()}finally{if(o)throw i}}return r}},{key:"removeUnusedKeyframes",value:function(){var e=!0,t=!1,r=void 0;try{for(var n,o=this.atRules.keyframes[Symbol.iterator]();!(e=(n=o.next()).done);e=!0){var i=n.value,a=i.params;this.usedAnimations.has(a)||i.remove()}}catch(e){t=!0,r=e}finally{try{!e&&o.return&&o.return()}finally{if(t)throw r}}}},{key:"removeUnusedFontFaces",value:function(){var e=!0,t=!1,r=void 0;try{for(var n,o=this.atRules.fontFace[Symbol.iterator]();!(e=(n=o.next()).done);e=!0){var i=n.value,a=i.node,s=i.name;this.usedFontFaces.has(s)||a.remove()}}catch(e){t=!0,r=e}finally{try{!e&&o.return&&o.return()}finally{if(t)throw r}}}},{key:"extractRawSelector",value:function(e,t){var r=new Set,n=!0,o=!1,i=void 0;try{for(var a,s=e[Symbol.iterator]();!(n=(a=s.next()).done);n=!0){var l=a.value,u=l.raw,c=l.extension,f=this.getFileExtractor("."+c,t);r=new Set([].concat(toConsumableArray(r),toConsumableArray(this.extractSelectors(u,f))))}}catch(e){o=!0,i=e}finally{try{!n&&s.return&&s.return()}finally{if(o)throw i}}return r}},{key:"extractFileSelector",value:function(e,t){var r=new Set,n=!0,o=!1,i=void 0;try{for(var a,s=e[Symbol.iterator]();!(n=(a=s.next()).done);n=!0){var l=a.value,u=[];fs.existsSync(l)?u.push(l):u=glob.sync(l);var c=!0,f=!1,y=void 0;try{for(var h,p=u[Symbol.iterator]();!(c=(h=p.next()).done);c=!0){var v=h.value,d=fs.readFileSync(v,"utf8"),E=this.getFileExtractor(v,t);r=new Set([].concat(toConsumableArray(r),toConsumableArray(this.extractSelectors(d,E))))}}catch(e){f=!0,y=e}finally{try{!c&&p.return&&p.return()}finally{if(f)throw y}}}}catch(e){o=!0,i=e}finally{try{!n&&s.return&&s.return()}finally{if(o)throw i}}return r}},{key:"getFileExtractor",value:function(e){var t=arguments.length>1&&void 0!==arguments[1]?arguments[1]:[];return t.length?t.find(function(t){return t.extensions.find(function(t){return e.endsWith(t)})}).extractor:!0===this.options.legacy?LegacyExtractor:DefaultExtractor}},{key:"extractSelectors",value:function(e,t){var r=new Set,n=t.extract(e);if(null===n)throw new Error(ERROR_EXTRACTER_FAILED);return n.forEach(function(e){r.add(e)}),r.delete(""),r}},{key:"getSelectorsCss",value:function(e){var t=this;this.root.walk(function(r){return"rule"===r.type?t.evaluateRule(r,e):"atrule"===r.type?t.evaluateAtRule(r):void 0})}},{key:"evaluateRule",value:function(e,t){var r=this,n=e.prev();if(!this.isIgnoreAnnotation(n)){var o=!0;if(e.selector=selectorParser(function(e){e.walk(function(e){var n=[];if("selector"===e.type){if(e.parent&&":not"===e.parent.value&&"pseudo"===e.parent.type)return;var i=!0,a=!1,s=void 0;try{for(var l,u=e.nodes[Symbol.iterator]();!(i=(l=u.next()).done);i=!0){var c=l.value,f=c.type,y=c.value;SELECTOR_STANDARD_TYPES.includes(f)&&void 0!==y?n.push(y):"tag"!==f||/[+]|(even)|(odd)|^from$|^to$|^\d/.test(y)||n.push(y)}}catch(e){a=!0,s=e}finally{try{!i&&u.return&&u.return()}finally{if(a)throw s}}(o=r.shouldKeepSelector(t,n))||e.remove()}})}).processSync(e.selector),o){var i=!0,a=!1,s=void 0;try{for(var l,u=e.nodes[Symbol.iterator]();!(i=(l=u.next()).done);i=!0){var c=l.value,f=c.prop,y=c.value;if(this.options.keyframes&&("animation"===f||"animation-name"===f)){var h=!0,p=!1,v=void 0;try{for(var d,E=y.split(" ")[Symbol.iterator]();!(h=(d=E.next()).done);h=!0){var R=d.value;this.usedAnimations.add(R)}}catch(e){p=!0,v=e}finally{try{!h&&E.return&&E.return()}finally{if(p)throw v}}}this.options.fontFace&&"font-family"===f&&this.usedFontFaces.add(y)}}catch(e){a=!0,s=e}finally{try{!i&&u.return&&u.return()}finally{if(a)throw s}}}var m=e.parent;e.selector||e.remove(),this.isRuleEmpty(m)&&m.remove()}}},{key:"evaluateAtRule",value:function(e){if(this.options.keyframes&&e.name.endsWith("keyframes"))this.atRules.keyframes.push(e);else if(this.options.fontFace&&"font-face"===e.name){var t=!0,r=!1,n=void 0;try{for(var o,i=e.nodes[Symbol.iterator]();!(t=(o=i.next()).done);t=!0){var a=o.value,s=a.prop,l=a.value;"font-family"===s&&this.atRules.fontFace.push({name:l,node:e})}}catch(e){r=!0,n=e}finally{try{!t&&i.return&&i.return()}finally{if(r)throw n}}}else;}},{key:"isIgnoreAnnotation",value:function(e){return!(!e||"comment"!==e.type)&&e.text.includes(IGNORE_ANNOTATION)}},{key:"isRuleEmpty",value:function(e){return!!("decl"===e.type&&!e.value||"rule"===e.type&&!e.selector||e.nodes&&!e.nodes.length||"atrule"===e.type&&(!e.nodes&&!e.params||!e.params&&!e.nodes.length))}},{key:"shouldKeepSelector",value:function(e,t){var r=!0,n=!1,o=void 0;try{for(var i,a=t[Symbol.iterator]();!(r=(i=a.next()).done);r=!0){var s=i.value;if(this.options.legacy){var l=s.split(/[^a-z]/g),u=!1,c=!0,f=!1,y=void 0;try{for(var h,p=l[Symbol.iterator]();!(c=(h=p.next()).done);c=!0){var v=h.value;if(v){if(!e.has(v))break;u=!0}}}catch(e){f=!0,y=e}finally{try{!c&&p.return&&p.return()}finally{if(f)throw y}}if(u)return!0;if(e.has(s)||CSS_WHITELIST.includes(s)||this.isSelectorWhitelisted(s))return!0}else{var d=s.replace(/\\/g,"");if(d.startsWith(":"))continue;if(!(e.has(d)||CSS_WHITELIST.includes(d)||this.isSelectorWhitelisted(d)))return!1}}}catch(e){n=!0,o=e}finally{try{!r&&a.return&&a.return()}finally{if(n)throw o}}return!this.options.legacy}},{key:"isSelectorWhitelisted",value:function(e){return!!(CSS_WHITELIST.includes(e)||this.options.whitelist&&this.options.whitelist.some(function(t){return t===e})||this.options.whitelistPatterns&&this.options.whitelistPatterns.some(function(t){return t.test(e)}))}}]),e}();module.exports=Purgecss;
diff --git a/src/constants/defaultOptions.js b/src/constants/defaultOptions.js
index 52027de8..ed9623a7 100644
--- a/src/constants/defaultOptions.js
+++ b/src/constants/defaultOptions.js
@@ -10,7 +10,8 @@ const defaultOptions: Options = {
     info: false,
     rejected: false,
     legacy: false,
-    keyframes: false
+    keyframes: false,
+    fontFace: false
 }
 
 export default defaultOptions
diff --git a/src/index.js b/src/index.js
index 08ba21bc..2107f9a3 100644
--- a/src/index.js
+++ b/src/index.js
@@ -31,9 +31,13 @@ import LegacyExtractor from './Extractors/LegacyExtractor'
 class Purgecss {
     options: Options
     root: Object
-    atRules: Object = {
-        keyframes: {}
+    atRules: AtRules = {
+        keyframes: [],
+        fontFace: []
     }
+    usedAnimations: Set<string> = new Set()
+    usedFontFaces: Set<string> = new Set()
+    selectorsRemoved: Set<string> = new Set()
 
     constructor(options: Options | string) {
         if (typeof options === 'string' || typeof options === 'undefined')
@@ -128,6 +132,9 @@ class Purgecss {
             // purge keyframes
             if (this.options.keyframes) this.removeUnusedKeyframes()
 
+            // purge font face
+            if (this.options.fontFace) this.removeUnusedFontFaces()
+
             sources.push({
                 file,
                 css: this.root.toString()
@@ -138,24 +145,28 @@ class Purgecss {
     }
 
     /**
-     * Remove Keyframes that are never used
+     * Remove Keyframes that were never used
      */
     removeUnusedKeyframes() {
-        const usedAnimations = new Set()
+        for (const node of this.atRules.keyframes) {
+            const nodeName = node.params
+            const used = this.usedAnimations.has(nodeName)
 
-        // list all used animations
-        this.root.walkDecls(/animation/, decl => {
-            for (const word of decl.value.split(' ')) {
-                usedAnimations.add(word)
+            if (!used) {
+                node.remove()
             }
-        })
+        }
+    }
 
-        // remove unused keyframes
-        for (const nodeName in this.atRules.keyframes) {
-            const keyframeUsed = usedAnimations.has(nodeName)
+    /**
+     * Remove Font-Faces that were never used
+     */
+    removeUnusedFontFaces() {
+        for (const { node, name } of this.atRules.fontFace) {
+            const used = this.usedFontFaces.has(name)
 
-            if (!keyframeUsed) {
-                this.atRules.keyframes[nodeName].remove()
+            if (!used) {
+                node.remove()
             }
         }
     }
@@ -237,59 +248,108 @@ class Purgecss {
      * @param {*} selectors selectors used in content files
      */
     getSelectorsCss(selectors: Set<string>) {
-        this.root.walkRules(node => {
-            const annotation = node.prev()
-            if (this.isIgnoreAnnotation(annotation)) return
-            node.selector = selectorParser(selectorsParsed => {
-                selectorsParsed.walk(selector => {
-                    const selectorsInRule = []
-                    if (selector.type === 'selector') {
-                        // if inside :not pseudo class, ignore
+        this.root.walk(node => {
+            if (node.type === 'rule') {
+                return this.evaluateRule(node, selectors)
+            }
+            if (node.type === 'atrule') {
+                return this.evaluateAtRule(node)
+            }
+        })
+    }
+
+    /**
+     * Evaluate css selector and decide if it should be removed or not
+     * @param {AST} node postcss ast node
+     * @param {Set} selectors selectors used in content files
+     */
+    evaluateRule(node: Object, selectors: Set<string>) {
+        const annotation = node.prev()
+        if (this.isIgnoreAnnotation(annotation)) return
+
+        let keepSelector = true
+        node.selector = selectorParser(selectorsParsed => {
+            selectorsParsed.walk(selector => {
+                const selectorsInRule = []
+                if (selector.type === 'selector') {
+                    // if inside :not pseudo class, ignore
+                    if (
+                        selector.parent &&
+                        selector.parent.value === ':not' &&
+                        selector.parent.type === 'pseudo'
+                    ) {
+                        return
+                    }
+                    for (const { type, value } of selector.nodes) {
                         if (
-                            selector.parent &&
-                            selector.parent.value === ':not' &&
-                            selector.parent.type === 'pseudo'
+                            SELECTOR_STANDARD_TYPES.includes(type) &&
+                            typeof value !== 'undefined'
                         ) {
-                            return
-                        }
-                        for (const { type, value } of selector.nodes) {
-                            if (
-                                SELECTOR_STANDARD_TYPES.includes(type) &&
-                                typeof value !== 'undefined'
-                            ) {
-                                selectorsInRule.push(value)
-                            } else if (
-                                type === 'tag' &&
-                                !/[+]|(even)|(odd)|^from$|^to$|^\d/.test(value)
-                            ) {
-                                // test if we do not have a pseudo class parameter (e.g. 2n in :nth-child(2n))
-                                selectorsInRule.push(value)
-                            }
+                            selectorsInRule.push(value)
+                        } else if (
+                            type === 'tag' &&
+                            !/[+]|(even)|(odd)|^from$|^to$|^\d/.test(value)
+                        ) {
+                            // test if we do not have a pseudo class parameter (e.g. 2n in :nth-child(2n))
+                            selectorsInRule.push(value)
                         }
+                    }
 
-                        let keepSelector = this.shouldKeepSelector(selectors, selectorsInRule)
+                    keepSelector = this.shouldKeepSelector(selectors, selectorsInRule)
 
-                        if (!keepSelector) {
-                            selector.remove()
+                    if (!keepSelector) {
+                        selector.remove()
+                    }
+                }
+            })
+        }).processSync(node.selector)
+
+        // loop declarations
+        if (keepSelector) {
+            for (const { prop, value } of node.nodes) {
+                if (this.options.keyframes) {
+                    if (prop === 'animation' || prop === 'animation-name') {
+                        for (const word of value.split(' ')) {
+                            this.usedAnimations.add(word)
                         }
                     }
-                })
-            }).processSync(node.selector)
+                }
+                if (this.options.fontFace) {
+                    if (prop === 'font-family') {
+                        this.usedFontFaces.add(value)
+                    }
+                }
+            }
+        }
 
-            const parent = node.parent
+        const parent = node.parent
 
-            // register atrules to purgecss
-            if (
-                parent.type === 'atrule' &&
-                (this.options.keyframes && parent.name === 'keyframes')
-            ) {
-                this.atRules.keyframes[parent.params] = parent
-            }
+        // Remove empty rules
+        if (!node.selector) node.remove()
+        if (this.isRuleEmpty(parent)) parent.remove()
+    }
 
-            // Remove empty rules
-            if (!node.selector) node.remove()
-            if (this.isRuleEmpty(parent)) parent.remove()
-        })
+    /**
+     * Evaluate at-rule and register it for future reference
+     * @param {AST} node postcss ast node
+     */
+    evaluateAtRule(node: Object) {
+        if (this.options.keyframes && node.name.endsWith('keyframes')) {
+            this.atRules.keyframes.push(node)
+            return
+        }
+
+        if (this.options.fontFace && node.name === 'font-face') {
+            for (const { prop, value } of node.nodes) {
+                if (prop === 'font-family') {
+                    this.atRules.fontFace.push({
+                        name: value,
+                        node
+                    })
+                }
+            }
+            return
+        }
     }
 
     /**