Add an option to specify the Highlight.js instance and provide a core plugin

README.md

@@ -1,4 +1,4 @@
-# markdown-it-highlightjs [![npm version](http://img.shields.io/npm/v/markdown-it-highlightjs.svg?style=flat-square)](https://www.npmjs.org/package/markdown-it-highlightjs)
+# markdown-it-highlightjs [![npm version](https://img.shields.io/npm/v/markdown-it-highlightjs.svg?style=flat-square)](https://www.npmjs.org/package/markdown-it-highlightjs)
 
 > Preset to use [highlight.js] with [markdown-it].
 
@@ -23,6 +23,7 @@ Name       | Type | Description
 `code`     | boolean | Whether to add the `hljs` class to raw code blocks (not fenced blocks). | `true`
 `register` | object  | Register other languages which are not included in the standard pack.   | `null`
 `inline`   | boolean | Whether to highlight inline code.                                       | `false`
+`hljs`     | object  | Provide the instance of [highlight.js] to use for highlighting          | `require('highlight.js')`
 
 ### Register languages
 
@@ -57,3 +58,29 @@ or [Kramdown IAL syntax](https://kramdown.gettalong.org/syntax.html#inline-attri
 ```
 
 If you do not specify a language, then highlight.js will attempt to guess the language if `auto` is true (which it is by default).
+
+### Provide the [highlight.js] instance
+
+You can specify the `hljs` option to override the default [highlight.js] instance with your own:
+
+```js
+const hljs = require('highlight.js/lib/core')
+
+hljs.registerLanguage(
+  'javascript',
+  require('highlight.js/lib/languages/javascript')
+)
+
+const md = require('markdown-it')()
+  .use(require('markdown-it-highlightjs'), { hljs })
+```
+
+### Core plugin
+
+You may import the core `markdown-it-highlightjs` plugin directly, without any default options. You must specify an instance of [highlight.js] for the `hljs` option.
+
+```js
+const hljs = require('highlight.js/lib/core')
+const md = require('markdown-it')()
+  .use(require('markdown-it-highlightjs/core'), { hljs })
+```

core.js

@@ -0,0 +1,76 @@
+function maybe (f) {
+  try {
+    return f()
+  } catch (e) {
+    return false
+  }
+}
+
+let hljs
+
+// Allow registration of other languages.
+const registerLangs = (register) => register &&
+  Object.entries(register).map(([lang, pack]) => { hljs.registerLanguage(lang, pack) })
+
+// Highlight with given language.
+const highlight = (code, lang) =>
+  maybe(() => hljs.highlight(lang || 'plaintext', code, true).value) || ''
+
+// Highlight with given language or automatically.
+const highlightAuto = (code, lang) =>
+  lang
+    ? highlight(code, lang)
+    : maybe(() => hljs.highlightAuto(code).value) || ''
+
+// Wrap a render function to add `hljs` class to code blocks.
+const wrap = render =>
+  function (...args) {
+    return render.apply(this, args)
+      .replace('<code class="', '<code class="hljs ')
+      .replace('<code>', '<code class="hljs">')
+  }
+
+function inlineCodeRenderer (md, tokens, idx, options) {
+  const code = tokens[idx]
+  const next = tokens[idx + 1]
+  let lang
+
+  if (next && next.type === 'text') {
+    // Match kramdown- or pandoc-style language specifier.
+    // e.g. `code`{:.ruby} or `code`{.haskell}
+    const match = /^{:?\.([^}]+)}/.exec(next.content)
+
+    if (match) {
+      lang = match[1]
+
+      // Remove the language specification from text following the code.
+      next.content = next.content.slice(match[0].length)
+    }
+  }
+
+  const highlighted = options.highlight(code.content, lang)
+  const cls = lang ? ` class="${options.langPrefix}${md.utils.escapeHtml(lang)}"` : ''
+
+  return `<code${cls}>${highlighted}</code>`
+}
+
+module.exports = (md, opts) => {
+  opts = Object.assign({}, opts)
+  hljs = opts.hljs
+  if (!hljs) {
+    throw new Error('A hljs instance is required.')
+  }
+
+  registerLangs(opts.register)
+
+  md.options.highlight = opts.auto ? highlightAuto : highlight
+  md.renderer.rules.fence = wrap(md.renderer.rules.fence)
+
+  if (opts.code) {
+    md.renderer.rules.code_block = wrap(md.renderer.rules.code_block)
+  }
+
+  if (opts.inline) {
+    md.renderer.rules.code_inline = inlineCodeRenderer.bind(null, md)
+  }
+}

index.js

@@ -1,73 +1,11 @@
-const hljs = require('highlight.js')
-
-function maybe (f) {
-  try {
-    return f()
-  } catch (e) {
-    return false
-  }
-}
-
-// Allow registration of other languages.
-const registerLangs = (register) => register &&
-  Object.entries(register).map(([lang, pack]) => { hljs.registerLanguage(lang, pack) })
-
-// Highlight with given language.
-const highlight = (code, lang) =>
-  maybe(() => hljs.highlight(lang || 'plaintext', code, true).value) || ''
-
-// Highlight with given language or automatically.
-const highlightAuto = (code, lang) =>
-  lang
-    ? highlight(code, lang)
-    : maybe(() => hljs.highlightAuto(code).value) || ''
-
-// Wrap a render function to add `hljs` class to code blocks.
-const wrap = render =>
-  function (...args) {
-    return render.apply(this, args)
-      .replace('<code class="', '<code class="hljs ')
-      .replace('<code>', '<code class="hljs">')
-  }
-
-function inlineCodeRenderer (md, tokens, idx, options) {
-  const code = tokens[idx]
-  const next = tokens[idx + 1]
-  let lang
-
-  if (next && next.type === 'text') {
-    // Match kramdown- or pandoc-style language specifier.
-    // e.g. `code`{:.ruby} or `code`{.haskell}
-    const match = /^{:?\.([^}]+)}/.exec(next.content)
-
-    if (match) {
-      lang = match[1]
-
-      // Remove the language specification from text following the code.
-      next.content = next.content.slice(match[0].length)
-    }
-  }
-
-  const highlighted = options.highlight(code.content, lang)
-  const cls = lang ? ` class="${options.langPrefix}${md.utils.escapeHtml(lang)}"` : ''
-
-  return `<code${cls}>${highlighted}</code>`
-}
-
 const highlightjs = (md, opts) => {
-  opts = Object.assign({}, highlightjs.defaults, opts)
-  registerLangs(opts.register)
-
-  md.options.highlight = opts.auto ? highlightAuto : highlight
-  md.renderer.rules.fence = wrap(md.renderer.rules.fence)
-
-  if (opts.code) {
-    md.renderer.rules.code_block = wrap(md.renderer.rules.code_block)
-  }
-
-  if (opts.inline) {
-    md.renderer.rules.code_inline = inlineCodeRenderer.bind(null, md)
-  }
+  opts = Object.assign(
+    {},
+    highlightjs.defaults,
+    { hljs: (opts && opts.hljs) || require('highlight.js') },
+    opts
+  )
+  return require('./core')(md, opts)
 }
 
 highlightjs.defaults = {

package.json

@@ -14,6 +14,7 @@
   "files": [
     "README.md",
     "UNLICENSE",
+    "core.js",
     "index.js"
   ],
   "repository": {

test.js

@@ -2,6 +2,22 @@ const { strictEqual: equal } = require('assert')
 const md = require('markdown-it')
 const highlightjs = require('./')
 
+equal(
+  (() => {
+    try {
+      return md().use(require('./core'))
+    } catch (ex) {
+      return ex.message
+    }
+  })(),
+  'A hljs instance is required.'
+)
+
+equal(
+  md().use(highlightjs, { hljs: require('highlight.js/lib/core') }).render('```js\nconsole.log(42)\n```'),
+  `<pre><code class="hljs language-js">console.log(42)\n</code></pre>
+`)
+
 equal(
   md().use(highlightjs).render('```js\nconsole.log(42)\n```'),
   `<pre><code class="hljs language-js"><span class="hljs-built_in">console</span>.log(<span class="hljs-number">42</span>)