Add support for keep option

Closes GH-15. Closes GH-17. Reviewed-by: Titus Wormer <[email protected]>
remarkjs · Aug 8, 2019 · e395323 · e395323
1 parent f92f73b
commit e395323
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Showing 2 changed files with 71 additions and 35 deletions.
diff --git a/index.js b/index.js
@@ -2,45 +2,62 @@
 
 module.exports = strip
 
-function strip() {
-  return one
-}
-
 // Expose modifiers for available node types.
 // Node types not listed here are not changed (but their children are).
-var map = {}
-
-map.heading = paragraph
-map.text = text
-map.inlineCode = text
-map.image = image
-map.imageReference = image
-map.break = lineBreak
-
-map.blockquote = children
-map.list = children
-map.listItem = children
-map.strong = children
-map.emphasis = children
-map.delete = children
-map.link = children
-map.linkReference = children
-
-map.code = empty
-map.horizontalRule = empty
-map.thematicBreak = empty
-map.html = empty
-map.table = empty
-map.tableCell = empty
-map.definition = empty
-map.yaml = empty
-map.toml = empty
+var map = {
+  heading: paragraph,
+  text: text,
+  inlineCode: text,
+  image: image,
+  imageReference: image,
+  break: lineBreak,
+
+  blockquote: children,
+  list: children,
+  listItem: children,
+  strong: children,
+  emphasis: children,
+  delete: children,
+  link: children,
+  linkReference: children,
+
+  code: empty,
+  horizontalRule: empty,
+  thematicBreak: empty,
+  html: empty,
+  table: empty,
+  tableCell: empty,
+  definition: empty,
+  yaml: empty,
+  toml: empty
+}
+var mapFiltered
+
+function strip(options) {
+  var keep = (options || {}).keep || []
+
+  // Remove node types specified in `keep` from map
+  mapFiltered = Object.assign({}, map)
+  keep.forEach(function(nodeType) {
+    if (nodeType in mapFiltered) {
+      delete mapFiltered[nodeType]
+    } else {
+      throw new Error(
+        'Invalid `keep` option: No modifier is defined for node type `' +
+          nodeType +
+          '`'
+      )
+    }
+  })
+
+  return one
+}
 
 function one(node) {
   var type = node && node.type
 
-  if (type in map) {
-    node = map[type](node)
+  if (type in mapFiltered) {
+    node = mapFiltered[type](node)
   }
 
   if ('length' in node) {

diff --git a/test.js b/test.js
@@ -5,9 +5,9 @@ var remark = require('remark')
 var u = require('unist-builder')
 var strip = require('.')
 
-function proc(value) {
+function proc(value, options) {
   return remark()
-    .use(strip)
+    .use(strip, options)
     .processSync(value)
     .toString()
     .trimRight()
@@ -83,5 +83,24 @@ test('stripMarkdown()', function(t) {
     'html (3)'
   )
 
+  // "keep" option
+  t.equal(
+    proc('- **Hello**\n\n- World!', {keep: []}),
+    'Hello\n\nWorld!',
+    'empty array as "keep" option'
+  )
+  t.equal(
+    proc('- **Hello**\n\n- World!', {keep: ['list', 'listItem']}),
+    '-   Hello\n\n-   World!',
+    'keep lists'
+  )
+  t.throws(
+    function() {
+      proc('- **Hello**\n\n- World!', {keep: ['typo']})
+    },
+    /Error: Invalid `keep` option/,
+    'invalid "keep" option'
+  )
+
   t.end()
 })