.config/coc/extensions/node_modules/coc-prettier/node_modules/unist-util-is/readme.md

   1 # unist-util-is
   2
   3 [![Build][build-badge]][build]
   4 [![Coverage][coverage-badge]][coverage]
   5 [![Downloads][downloads-badge]][downloads]
   6 [![Size][size-badge]][size]
   7 [![Sponsors][sponsors-badge]][collective]
   8 [![Backers][backers-badge]][collective]
   9 [![Chat][chat-badge]][chat]
  10
  11 [**unist**][unist] utility to check if a node passes a test.
  12
  13 ## Install
  14
  15 [npm][]:
  16
  17 ```sh
  18 npm install unist-util-is
  19 ```
  20
  21 ## Usage
  22
  23 ```js
  24 var is = require('unist-util-is')
  25
  26 var node = {type: 'strong'}
  27 var parent = {type: 'paragraph', children: [node]}
  28
  29 function test(node, n) {
  30   return n === 5
  31 }
  32
  33 is() // => false
  34 is({children: []}) // => false
  35 is(node) // => true
  36 is(node, 'strong') // => true
  37 is(node, 'emphasis') // => false
  38
  39 is(node, node) // => true
  40 is(parent, {type: 'paragraph'}) // => true
  41 is(parent, {type: 'strong'}) // => false
  42
  43 is(node, test) // => false
  44 is(node, test, 4, parent) // => false
  45 is(node, test, 5, parent) // => true
  46 ```
  47
  48 ## API
  49
  50 ### `is(node[, test[, index, parent[, context]]])`
  51
  52 ###### Parameters
  53
  54 *   `node` ([`Node`][node]) — Node to check.
  55 *   `test` ([`Function`][test], `string`, `Object`, or `Array.<Test>`, optional)
  56     —  When not given, checks if `node` is a [`Node`][node].
  57     When `string`, works like passing `node => node.type === test`.
  58     When `array`, checks if any one of the subtests pass.
  59     When `object`, checks that all keys in `test` are in `node`,
  60     and that they have strictly equal values
  61 *   `index` (`number`, optional) — [Index][] of `node` in `parent`
  62 *   `parent` ([`Node`][node], optional) — [Parent][] of `node`
  63 *   `context` (`*`, optional) — Context object to invoke `test` with
  64
  65 ###### Returns
  66
  67 `boolean` — Whether `test` passed *and* `node` is a [`Node`][node] (object with
  68 `type` set to a non-empty `string`).
  69
  70 #### `function test(node[, index, parent])`
  71
  72 ###### Parameters
  73
  74 *   `node` ([`Node`][node]) — Node to check
  75 *   `index` (`number?`) — [Index][] of `node` in `parent`
  76 *   `parent` ([`Node?`][node]) — [Parent][] of `node`
  77
  78 ###### Context
  79
  80 `*` — The to `is` given `context`.
  81
  82 ###### Returns
  83
  84 `boolean?` — Whether `node` matches.
  85
  86 ### `is.convert(test)`
  87
  88 Create a test function from `test`, that can later be called with a `node`,
  89 `index`, and `parent`.
  90 Useful if you’re going to test many nodes, for example when creating a utility
  91 where something else passes an is-compatible test.
  92
  93 Can also be accessed with `require('unist-util-is/convert')`.
  94
  95 For example:
  96
  97 ```js
  98 var u = require('unist-builder')
  99 var convert = require('unist-util-is/convert')
 100
 101 var test = convert('leaf')
 102
 103 var tree = u('tree', [
 104   u('node', [u('leaf', '1')]),
 105   u('leaf', '2'),
 106   u('node', [u('leaf', '3'), u('leaf', '4')]),
 107   u('leaf', '5')
 108 ])
 109
 110 var leafs = tree.children.filter((child, index) => test(child, index, tree))
 111
 112 console.log(leafs)
 113 ```
 114
 115 Yields:
 116
 117 ```js
 118 [({type: 'leaf', value: '2'}, {type: 'leaf', value: '5'})]
 119 ```
 120
 121 ## Related
 122
 123 *   [`unist-util-find-after`](https://github.com/syntax-tree/unist-util-find-after)
 124     — Find a node after another node
 125 *   [`unist-util-find-before`](https://github.com/syntax-tree/unist-util-find-before)
 126     — Find a node before another node
 127 *   [`unist-util-find-all-after`](https://github.com/syntax-tree/unist-util-find-all-after)
 128     — Find all nodes after another node
 129 *   [`unist-util-find-all-before`](https://github.com/syntax-tree/unist-util-find-all-before)
 130     — Find all nodes before another node
 131 *   [`unist-util-find-all-between`](https://github.com/mrzmmr/unist-util-find-all-between)
 132     — Find all nodes between two nodes
 133 *   [`unist-util-find`](https://github.com/blahah/unist-util-find)
 134     — Find nodes matching a predicate
 135 *   [`unist-util-filter`](https://github.com/eush77/unist-util-filter)
 136     — Create a new tree with nodes that pass a check
 137 *   [`unist-util-remove`](https://github.com/eush77/unist-util-remove)
 138     — Remove nodes from tree
 139
 140 ## Contribute
 141
 142 See [`contributing.md` in `syntax-tree/.github`][contributing] for ways to get
 143 started.
 144 See [`support.md`][support] for ways to get help.
 145
 146 This project has a [Code of Conduct][coc].
 147 By interacting with this repository, organisation, or community you agree to
 148 abide by its terms.
 149
 150 ## License
 151
 152 [MIT][license] © [Titus Wormer][author]
 153
 154 <!-- Definitions -->
 155
 156 [build-badge]: https://img.shields.io/travis/syntax-tree/unist-util-is.svg
 157
 158 [build]: https://travis-ci.org/syntax-tree/unist-util-is
 159
 160 [coverage-badge]: https://img.shields.io/codecov/c/github/syntax-tree/unist-util-is.svg
 161
 162 [coverage]: https://codecov.io/github/syntax-tree/unist-util-is
 163
 164 [downloads-badge]: https://img.shields.io/npm/dm/unist-util-is.svg
 165
 166 [downloads]: https://www.npmjs.com/package/unist-util-is
 167
 168 [size-badge]: https://img.shields.io/bundlephobia/minzip/unist-util-is.svg
 169
 170 [size]: https://bundlephobia.com/result?p=unist-util-is
 171
 172 [sponsors-badge]: https://opencollective.com/unified/sponsors/badge.svg
 173
 174 [backers-badge]: https://opencollective.com/unified/backers/badge.svg
 175
 176 [collective]: https://opencollective.com/unified
 177
 178 [chat-badge]: https://img.shields.io/badge/join%20the%20community-on%20spectrum-7b16ff.svg
 179
 180 [chat]: https://spectrum.chat/unified/syntax-tree
 181
 182 [npm]: https://docs.npmjs.com/cli/install
 183
 184 [license]: license
 185
 186 [author]: https://wooorm.com
 187
 188 [contributing]: https://github.com/syntax-tree/.github/blob/master/contributing.md
 189
 190 [support]: https://github.com/syntax-tree/.github/blob/master/support.md
 191
 192 [coc]: https://github.com/syntax-tree/.github/blob/master/code-of-conduct.md
 193
 194 [unist]: https://github.com/syntax-tree/unist
 195
 196 [node]: https://github.com/syntax-tree/unist#node
 197
 198 [parent]: https://github.com/syntax-tree/unist#parent-1
 199
 200 [index]: https://github.com/syntax-tree/unist#index
 201
 202 [test]: #function-testnode-index-parent