Require Node.js 8 and Gulp 4

Fixes #113

.travis.yml

@@ -1,5 +1,5 @@
 language: node_js
 node_js:
+  - '12'
   - '10'
   - '8'
-  - '6'

index.js

@@ -18,39 +18,43 @@ module.exports = options => {
 			return;
 		}
 
-		postcss(autoprefixer(options)).process(file.contents.toString(), {
-			map: file.sourceMap ? {annotation: false} : false,
-			from: file.path,
-			to: file.path
-		}).then(result => {
-			file.contents = Buffer.from(result.css);
-
-			if (result.map && file.sourceMap) {
-				const map = result.map.toJSON();
-				map.file = file.relative;
-				map.sources = map.sources.map(() => file.relative);
-				applySourceMap(file, map);
+		(async () => {
+			try {
+				const result = await postcss(autoprefixer(options)).process(file.contents.toString(), {
+					map: file.sourceMap ? {annotation: false} : false,
+					from: file.path,
+					to: file.path
+				});
+
+				file.contents = Buffer.from(result.css);
+
+				if (result.map && file.sourceMap) {
+					const map = result.map.toJSON();
+					map.file = file.relative;
+					map.sources = map.sources.map(() => file.relative);
+					applySourceMap(file, map);
+				}
+
+				const warnings = result.warnings();
+
+				if (warnings.length > 0) {
+					fancyLog('gulp-autoprefixer:', '\n  ' + warnings.join('\n  '));
+				}
+
+				setImmediate(callback, null, file);
+			} catch (error) {
+				const cssError = error.name === 'CssSyntaxError';
+
+				if (cssError) {
+					error.message += error.showSourceCode();
+				}
+
+				// Prevent stream unhandled exception from being suppressed by Promise
+				setImmediate(callback, new PluginError('gulp-autoprefixer', error, {
+					fileName: file.path,
+					showStack: !cssError
+				}));
 			}
-
-			const warnings = result.warnings();
-
-			if (warnings.length > 0) {
-				fancyLog('gulp-autoprefixer:', '\n  ' + warnings.join('\n  '));
-			}
-
-			setImmediate(callback, null, file);
-		}).catch(error => {
-			const cssError = error.name === 'CssSyntaxError';
-
-			if (cssError) {
-				error.message += error.showSourceCode();
-			}
-
-			// Prevent stream unhandled exception from being suppressed by Promise
-			setImmediate(callback, new PluginError('gulp-autoprefixer', error, {
-				fileName: file.path,
-				showStack: !cssError
-			}));
-		});
+		})();
 	});
 };

package.json

@@ -10,7 +10,7 @@
 		"url": "sindresorhus.com"
 	},
 	"engines": {
-		"node": ">=6"
+		"node": ">=8"
 	},
 	"scripts": {
 		"test": "xo && ava"
@@ -30,18 +30,21 @@
 		"postcss-runner"
 	],
 	"dependencies": {
-		"autoprefixer": "^9.5.1",
+		"autoprefixer": "^9.6.1",
 		"fancy-log": "^1.3.2",
 		"plugin-error": "^1.0.1",
-		"postcss": "^7.0.2",
+		"postcss": "^7.0.17",
 		"through2": "^3.0.1",
 		"vinyl-sourcemaps-apply": "^0.2.1"
 	},
 	"devDependencies": {
-		"ava": "^1.4.1",
+		"ava": "^2.3.0",
 		"gulp-sourcemaps": "^2.6.0",
-		"p-event": "^2.3.1",
+		"p-event": "^4.1.0",
 		"vinyl": "^2.1.0",
 		"xo": "^0.24.0"
+	},
+	"peerDependencies": {
+		"gulp": ">=4"
 	}
 }

readme.md

@@ -18,10 +18,9 @@ $ npm install --save-dev gulp-autoprefixer
 const gulp = require('gulp');
 const autoprefixer = require('gulp-autoprefixer');
 
-gulp.task('default', () =>
+exports.default = () => (
 	gulp.src('src/app.css')
 		.pipe(autoprefixer({
-			browsers: ['last 2 versions'],
 			cascade: false
 		}))
 		.pipe(gulp.dest('dist'))
@@ -31,7 +30,7 @@ gulp.task('default', () =>
 
 ## API
 
-### autoprefixer([options])
+### autoprefixer(options?)
 
 #### options
 
@@ -50,7 +49,7 @@ const sourcemaps = require('gulp-sourcemaps');
 const autoprefixer = require('gulp-autoprefixer');
 const concat = require('gulp-concat');
 
-gulp.task('default', () =>
+exports.default = () => (
 	gulp.src('src/**/*.css')
 		.pipe(sourcemaps.init())
 		.pipe(autoprefixer())

test.js

@@ -28,7 +28,7 @@ test('generate source maps', async t => {
 
 	init
 		.pipe(autoprefixer({
-			browsers: ['Firefox ESR']
+			overrideBrowserslist: ['Firefox ESR']
 		}))
 		.pipe(write);