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# unist-util-visit [![Build Status][build-badge]][build-page] [![Coverage Status][coverage-badge]][coverage-page]
[Unist][] node visitor. Useful when working with [**remark**][remark],
[**retext**][retext], or [**rehype**][rehype].
## Installation
[npm][]:
```bash
npm install unist-util-visit
```
## Usage
```javascript
var remark = require('remark');
var visit = require('unist-util-visit');
var tree = remark.parse('Some _emphasis_, **importance**, and `code`.');
visit(tree, 'text', visitor);
function visitor(node) {
console.log(node);
}
```
Yields:
```js
{ type: 'text', value: 'Some ' }
{ type: 'text', value: 'emphasis' }
{ type: 'text', value: ', ' }
{ type: 'text', value: 'importance' }
{ type: 'text', value: ', and ' }
{ type: 'text', value: '.' }
```
## API
### `visit(node[, test], visitor[, reverse])`
Visit nodes. Optionally filtering nodes. Optionally in reverse.
###### Parameters
* `node` ([`Node`][node])
— Node to search
* `test` ([`Test`][is], optional)
— Node type or other [`is`][is]-compatible test
* `visitor` ([Function][visitor])
— Visitor invoked when a node is found
* `reverse` (`boolean`, default: `false`)
— When falsey, checking starts at the first child and continues
through to later children. When truthy, this is reversed.
This **does not** mean checking starts at the deepest node and
continues on to the highest node
#### `stop? = visitor(node, index, parent)`
Invoked when a node (matching `test`, if given) is found.
###### Parameters
* `node` (`Node`) — Found node
* `index` (`number?`) — Position of `node` in `parent`
* `parent` (`Node?`) — Parent of `node`
###### Returns
`boolean?` - When `false`, visiting is immediately stopped.
## Related
* [`unist-util-visit-parents`](https://github.com/syntax-tree/unist-util-visit-parents)
— Like `visit`, but with a stack of parents
* [`unist-util-filter`](https://github.com/eush77/unist-util-filter)
— Create a new tree with all nodes that pass a test
* [`unist-util-map`](https://github.com/syntax-tree/unist-util-map)
— Create a new tree with all nodes mapped by a given function
* [`unist-util-remove`](https://github.com/eush77/unist-util-remove)
— Remove nodes from a tree that pass a test
* [`unist-util-select`](https://github.com/eush77/unist-util-select)
— Select nodes with CSS-like selectors
## License
[MIT][license] © [Titus Wormer][author]
<!-- Definition -->
[build-badge]: https://img.shields.io/travis/syntax-tree/unist-util-visit.svg
[build-page]: https://travis-ci.org/syntax-tree/unist-util-visit
[coverage-badge]: https://img.shields.io/codecov/c/github/syntax-tree/unist-util-visit.svg
[coverage-page]: https://codecov.io/github/syntax-tree/unist-util-visit?branch=master
[npm]: https://docs.npmjs.com/cli/install
[license]: LICENSE
[author]: http://wooorm.com
[unist]: https://github.com/syntax-tree/unist
[retext]: https://github.com/wooorm/retext
[remark]: https://github.com/wooorm/remark
[rehype]: https://github.com/wooorm/rehype
[node]: https://github.com/syntax-tree/unist#node
[is]: https://github.com/syntax-tree/unist-util-is#istest-node-index-parent-context
[visitor]: #stop--visitornode-index-parent
|
