Add light plugin

Closes GH-14.

Reviewed-by: Titus Wormer <[email protected]>

core.js

@@ -0,0 +1,112 @@
+'use strict'
+
+var toText = require('hast-util-to-text')
+var visit = require('unist-util-visit')
+
+module.exports = createPlugin
+
+function createPlugin(lowlight) {
+  return function (options) {
+    var settings = options || {}
+    var name = 'hljs'
+    var pos
+
+    if (settings.aliases) {
+      lowlight.registerAlias(settings.aliases)
+    }
+
+    if (settings.languages) {
+      // eslint-disable-next-line guard-for-in
+      for (let name in settings.languages) {
+        lowlight.registerLanguage(name, settings.languages[name])
+      }
+    }
+
+    if (settings.prefix) {
+      pos = settings.prefix.indexOf('-')
+      name = pos > -1 ? settings.prefix.slice(0, pos) : settings.prefix
+    }
+
+    return transformer
+
+    function transformer(tree) {
+      visit(tree, 'element', visitor)
+    }
+
+    function visitor(node, index, parent) {
+      var props
+      var result
+      var lang
+
+      if (!parent || parent.tagName !== 'pre' || node.tagName !== 'code') {
+        return
+      }
+
+      lang = language(node)
+
+      if (
+        lang === false ||
+        (!lang && settings.subset === false) ||
+        (settings.plainText && settings.plainText.indexOf(lang) > -1)
+      ) {
+        return
+      }
+
+      props = node.properties
+
+      if (!props.className) {
+        props.className = []
+      }
+
+      if (props.className.indexOf(name) < 0) {
+        props.className.unshift(name)
+      }
+
+      try {
+        result = lang
+          ? lowlight.highlight(lang, toText(parent), options)
+          : lowlight.highlightAuto(toText(parent), options)
+      } catch (error) {
+        if (
+          !settings.ignoreMissing ||
+          !/Unknown language/.test(error.message)
+        ) {
+          throw error
+        }
+
+        result = {}
+      }
+
+      if (!lang && result.language) {
+        props.className.push('language-' + result.language)
+      }
+
+      if (result.value) {
+        node.children = result.value
+      }
+    }
+  }
+}
+
+// Get the programming language of `node`.
+function language(node) {
+  var className = node.properties.className || []
+  var index = -1
+  var value
+
+  while (++index < className.length) {
+    value = className[index]
+
+    if (value === 'no-highlight' || value === 'nohighlight') {
+      return false
+    }
+
+    if (value.slice(0, 5) === 'lang-') {
+      return value.slice(5)
+    }
+
+    if (value.slice(0, 9) === 'language-') {
+      return value.slice(9)
+    }
+  }
+}

index.js

@@ -1,108 +1,5 @@
 'use strict'
-
-var toText = require('hast-util-to-text')
 var lowlight = require('lowlight')
-var visit = require('unist-util-visit')
-
-module.exports = attacher
-
-function attacher(options) {
-  var settings = options || {}
-  var name = 'hljs'
-  var pos
-
-  if (settings.aliases) {
-    lowlight.registerAlias(settings.aliases)
-  }
-
-  if (settings.languages) {
-    // eslint-disable-next-line guard-for-in
-    for (let name in settings.languages) {
-      lowlight.registerLanguage(name, settings.languages[name])
-    }
-  }
-
-  if (settings.prefix) {
-    pos = settings.prefix.indexOf('-')
-    name = pos > -1 ? settings.prefix.slice(0, pos) : settings.prefix
-  }
-
-  return transformer
-
-  function transformer(tree) {
-    visit(tree, 'element', visitor)
-  }
-
-  function visitor(node, index, parent) {
-    var props
-    var result
-    var lang
-
-    if (!parent || parent.tagName !== 'pre' || node.tagName !== 'code') {
-      return
-    }
-
-    lang = language(node)
-
-    if (
-      lang === false ||
-      (!lang && settings.subset === false) ||
-      (settings.plainText && settings.plainText.indexOf(lang) > -1)
-    ) {
-      return
-    }
-
-    props = node.properties
-
-    if (!props.className) {
-      props.className = []
-    }
-
-    if (props.className.indexOf(name) < 0) {
-      props.className.unshift(name)
-    }
-
-    try {
-      result = lang
-        ? lowlight.highlight(lang, toText(parent), options)
-        : lowlight.highlightAuto(toText(parent), options)
-    } catch (error) {
-      if (!settings.ignoreMissing || !/Unknown language/.test(error.message)) {
-        throw error
-      }
-
-      result = {}
-    }
-
-    if (!lang && result.language) {
-      props.className.push('language-' + result.language)
-    }
-
-    if (result.value) {
-      node.children = result.value
-    }
-  }
-}
-
-// Get the programming language of `node`.
-function language(node) {
-  var className = node.properties.className || []
-  var index = -1
-  var value
-
-  while (++index < className.length) {
-    value = className[index]
-
-    if (value === 'no-highlight' || value === 'nohighlight') {
-      return false
-    }
-
-    if (value.slice(0, 5) === 'lang-') {
-      return value.slice(5)
-    }
+var createPlugin = require('./core')
 
-    if (value.slice(0, 9) === 'language-') {
-      return value.slice(9)
-    }
-  }
-}
+module.exports = createPlugin(lowlight)

light.js

@@ -0,0 +1,5 @@
+'use strict'
+var lowlight = require('lowlight/lib/core')
+var createPlugin = require('./core')
+
+module.exports = createPlugin(lowlight)

package.json

@@ -25,7 +25,9 @@
     "Titus Wormer <[email protected]> (https://wooorm.com)"
   ],
   "files": [
-    "index.js"
+    "core.js",
+    "index.js",
+    "light.js"
   ],
   "dependencies": {
     "hast-util-to-text": "^2.0.0",

readme.md

@@ -105,6 +105,37 @@ Register more languages (`Object<string | function>`, default: `{}`).
 Each key/value pair passed as arguments to
 [`lowlight.registerLanguage`][register-language].
 
+## Browser
+
+It is not suggested to require `rehype-highlight` in the browser as it will
+include all the highlighters.
+
+> :warning: Please configure `languages`, as otherwise nothing gets highlighted.
+
+In the example below, only the JavaScript and TypeScript
+highlighters are included:
+
+```js
+var vfile = require('to-vfile')
+var report = require('vfile-reporter')
+var rehype = require('rehype')
+var highlight = require('rehype-highlight/light')
+
+rehype()
+  .data('settings', {fragment: true})
+  .use(highlight, {
+    // Don’t forget to define the languages you need
+    languages: {
+      javascript: require('highlight.js/lib/languages/javascript'),
+      typescript: require('highlight.js/lib/languages/typescript')
+    }
+  })
+  .process(vfile.readSync('example.html'), function (error, file) {
+    console.error(report(error || file))
+    console.log(String(file))
+  })
+```
+
 ## Security
 
 Use of `rehype-highlight` *should* be safe to use as `lowlight` *should* be safe