# snapdragon-node [](https://www.npmjs.com/package/snapdragon-node) [](https://npmjs.org/package/snapdragon-node) [](https://npmjs.org/package/snapdragon-node) [](https://travis-ci.org/jonschlinkert/snapdragon-node)
> Snapdragon utility for creating a new AST node in custom code, such as plugins.
## Install
Install with [npm](https://www.npmjs.com/):
```sh
$ npm install --save snapdragon-node
```
## Usage
With [snapdragon](https://github.com/jonschlinkert/snapdragon) v0.9.0 and higher you can use `this.node()` to create a new `Node`, whenever it makes sense.
```js
var Node = require('snapdragon-node');
var Snapdragon = require('snapdragon');
var snapdragon = new Snapdragon();
// example usage inside a parser visitor function
snapdragon.parser.set('foo', function() {
// get the current "start" position
var pos = this.position();
// returns the match if regex matches the substring
// at the current position on `parser.input`
var match = this.match(/foo/);
if (match) {
// call "pos" on the node, to set the start and end
// positions, and return the node to push it onto the AST
// (snapdragon will push the node onto the correct
// nodes array, based on the stack)
return pos(new Node({type: 'bar', val: match[0]}));
}
});
```
## API
### [Node](index.js#L22)
Create a new AST `Node` with the given `val` and `type`.
**Params**
* `val` **{String|Object}**: Pass a matched substring, or an object to merge onto the node.
* `type` **{String}**: The node type to use when `val` is a string.
* `returns` **{Object}**: node instance
**Example**
```js
var node = new Node('*', 'Star');
var node = new Node({type: 'star', val: '*'});
```
### [.isNode](index.js#L61)
Returns true if the given value is a node.
**Params**
* `node` **{Object}**
* `returns` **{Boolean}**
**Example**
```js
var Node = require('snapdragon-node');
var node = new Node({type: 'foo'});
console.log(Node.isNode(node)); //=> true
console.log(Node.isNode({})); //=> false
```
### [.define](index.js#L80)
Define a non-enumberable property on the node instance. Useful for adding properties that shouldn't be extended or visible during debugging.
**Params**
* `name` **{String}**
* `val` **{any}**
* `returns` **{Object}**: returns the node instance
**Example**
```js
var node = new Node();
node.define('foo', 'something non-enumerable');
```
### [.isEmpty](index.js#L100)
Returns true if `node.val` is an empty string, or `node.nodes` does not contain any non-empty text nodes.
**Params**
* `fn` **{Function}**: (optional) Filter function that is called on `node` and/or child nodes. `isEmpty` will return false immediately when the filter function returns false on any nodes.
* `returns` **{Boolean}**
**Example**
```js
var node = new Node({type: 'text'});
node.isEmpty(); //=> true
node.val = 'foo';
node.isEmpty(); //=> false
```
### [.push](index.js#L118)
Given node `foo` and node `bar`, push node `bar` onto `foo.nodes`, and set `foo` as `bar.parent`.
**Params**
* `node` **{Object}**
* `returns` **{Number}**: Returns the length of `node.nodes`
**Example**
```js
var foo = new Node({type: 'foo'});
var bar = new Node({type: 'bar'});
foo.push(bar);
```
### [.unshift](index.js#L140)
Given node `foo` and node `bar`, unshift node `bar` onto `foo.nodes`, and set `foo` as `bar.parent`.
**Params**
* `node` **{Object}**
* `returns` **{Number}**: Returns the length of `node.nodes`
**Example**
```js
var foo = new Node({type: 'foo'});
var bar = new Node({type: 'bar'});
foo.unshift(bar);
```
### [.pop](index.js#L167)
Pop a node from `node.nodes`.
* `returns` **{Number}**: Returns the popped `node`
**Example**
```js
var node = new Node({type: 'foo'});
node.push(new Node({type: 'a'}));
node.push(new Node({type: 'b'}));
node.push(new Node({type: 'c'}));
node.push(new Node({type: 'd'}));
console.log(node.nodes.length);
//=> 4
node.pop();
console.log(node.nodes.length);
//=> 3
```
### [.shift](index.js#L190)
Shift a node from `node.nodes`.
* `returns` **{Object}**: Returns the shifted `node`
**Example**
```js
var node = new Node({type: 'foo'});
node.push(new Node({type: 'a'}));
node.push(new Node({type: 'b'}));
node.push(new Node({type: 'c'}));
node.push(new Node({type: 'd'}));
console.log(node.nodes.length);
//=> 4
node.shift();
console.log(node.nodes.length);
//=> 3
```
### [.remove](index.js#L205)
Remove `node` from `node.nodes`.
**Params**
* `node` **{Object}**
* `returns` **{Object}**: Returns the removed node.
**Example**
```js
node.remove(childNode);
```
### [.find](index.js#L231)
Get the first child node from `node.nodes` that matches the given `type`. If `type` is a number, the child node at that index is returned.
**Params**
* `type` **{String}**
* `returns` **{Object}**: Returns a child node or undefined.
**Example**
```js
var child = node.find(1); //<= index of the node to get
var child = node.find('foo'); //<= node.type of a child node
var child = node.find(/^(foo|bar)$/); //<= regex to match node.type
var child = node.find(['foo', 'bar']); //<= array of node.type(s)
```
### [.isType](index.js#L249)
Return true if the node is the given `type`.
**Params**
* `type` **{String}**
* `returns` **{Boolean}**
**Example**
```js
var node = new Node({type: 'bar'});
cosole.log(node.isType('foo')); // false
cosole.log(node.isType(/^(foo|bar)$/)); // true
cosole.log(node.isType(['foo', 'bar'])); // true
```
### [.hasType](index.js#L270)
Return true if the `node.nodes` has the given `type`.
**Params**
* `type` **{String}**
* `returns` **{Boolean}**
**Example**
```js
var foo = new Node({type: 'foo'});
var bar = new Node({type: 'bar'});
foo.push(bar);
cosole.log(foo.hasType('qux')); // false
cosole.log(foo.hasType(/^(qux|bar)$/)); // true
cosole.log(foo.hasType(['qux', 'bar'])); // true
```
* `returns` **{Array}**
**Example**
```js
var foo = new Node({type: 'foo'});
var bar = new Node({type: 'bar'});
var baz = new Node({type: 'baz'});
foo.push(bar);
foo.push(baz);
console.log(bar.siblings.length) // 2
console.log(baz.siblings.length) // 2
```
* `returns` **{Number}**
**Example**
```js
var foo = new Node({type: 'foo'});
var bar = new Node({type: 'bar'});
var baz = new Node({type: 'baz'});
var qux = new Node({type: 'qux'});
foo.push(bar);
foo.push(baz);
foo.unshift(qux);
console.log(bar.index) // 1
console.log(baz.index) // 2
console.log(qux.index) // 0
```
* `returns` **{Object}**
**Example**
```js
var foo = new Node({type: 'foo'});
var bar = new Node({type: 'bar'});
var baz = new Node({type: 'baz'});
foo.push(bar);
foo.push(baz);
console.log(baz.prev.type) // 'bar'
```
* `returns` **{Object}**
**Example**
```js
var foo = new Node({type: 'foo'});
var bar = new Node({type: 'bar'});
var baz = new Node({type: 'baz'});
foo.push(bar);
foo.push(baz);
console.log(bar.siblings.length) // 2
console.log(baz.siblings.length) // 2
```
* `returns` **{Object}**: The first node, or undefiend
**Example**
```js
var foo = new Node({type: 'foo'});
var bar = new Node({type: 'bar'});
var baz = new Node({type: 'baz'});
var qux = new Node({type: 'qux'});
foo.push(bar);
foo.push(baz);
foo.push(qux);
console.log(foo.first.type) // 'bar'
```
* `returns` **{Object}**: The last node, or undefiend
**Example**
```js
var foo = new Node({type: 'foo'});
var bar = new Node({type: 'bar'});
var baz = new Node({type: 'baz'});
var qux = new Node({type: 'qux'});
foo.push(bar);
foo.push(baz);
foo.push(qux);
console.log(foo.last.type) // 'qux'
```
* `returns` **{Object}**: The last node, or undefiend
**Example**
```js
var foo = new Node({type: 'foo'});
var bar = new Node({type: 'bar'});
var baz = new Node({type: 'baz'});
var qux = new Node({type: 'qux'});
foo.push(bar);
foo.push(baz);
foo.push(qux);
console.log(foo.last.type) // 'qux'
```
## Release history
Changelog entries are classified using the following labels from [keep-a-changelog](https://github.com/olivierlacan/keep-a-changelog):
* `added`: for new features
* `changed`: for changes in existing functionality
* `deprecated`: for once-stable features removed in upcoming releases
* `removed`: for deprecated features removed in this release
* `fixed`: for any bug fixes
Custom labels used in this changelog:
* `dependencies`: bumps dependencies
* `housekeeping`: code re-organization, minor edits, or other changes that don't fit in one of the other categories.
### [2.0.0] - 2017-05-01
**Changed**
* `.unshiftNode` was renamed to [.unshift](#unshift)
* `.pushNode` was renamed to [.push](#push)
* `.getNode` was renamed to [.find](#find)
**Added**
* [.isNode](#isNode)
* [.isEmpty](#isEmpty)
* [.pop](#pop)
* [.shift](#shift)
* [.remove](#remove)
### [0.1.0]
First release.
## About
### Related projects
* [breakdance](https://www.npmjs.com/package/breakdance): Breakdance is a node.js library for converting HTML to markdown. Highly pluggable, flexible and easy… [more](http://breakdance.io) | [homepage](http://breakdance.io "Breakdance is a node.js library for converting HTML to markdown. Highly pluggable, flexible and easy to use. It's time for your markup to get down.")
* [snapdragon-capture](https://www.npmjs.com/package/snapdragon-capture): Snapdragon plugin that adds a capture method to the parser instance. | [homepage](https://github.com/jonschlinkert/snapdragon-capture "Snapdragon plugin that adds a capture method to the parser instance.")
* [snapdragon-cheerio](https://www.npmjs.com/package/snapdragon-cheerio): Snapdragon plugin for converting a cheerio AST to a snapdragon AST. | [homepage](https://github.com/jonschlinkert/snapdragon-cheerio "Snapdragon plugin for converting a cheerio AST to a snapdragon AST.")
* [snapdragon-util](https://www.npmjs.com/package/snapdragon-util): Utilities for the snapdragon parser/compiler. | [homepage](https://github.com/jonschlinkert/snapdragon-util "Utilities for the snapdragon parser/compiler.")
* [snapdragon](https://www.npmjs.com/package/snapdragon): Easy-to-use plugin system for creating powerful, fast and versatile parsers and compilers, with built-in source-map… [more](https://github.com/jonschlinkert/snapdragon) | [homepage](https://github.com/jonschlinkert/snapdragon "Easy-to-use plugin system for creating powerful, fast and versatile parsers and compilers, with built-in source-map support.")
### Contributing
Pull requests and stars are always welcome. For bugs and feature requests, [please create an issue](../../issues/new).
Please read the [contributing guide](.github/contributing.md) for advice on opening issues, pull requests, and coding standards.
### Building docs
_(This project's readme.md is generated by [verb](https://github.com/verbose/verb-generate-readme), please don't edit the readme directly. Any changes to the readme must be made in the [.verb.md](.verb.md) readme template.)_
To generate the readme, run the following command:
```sh
$ npm install -g verbose/verb#dev verb-generate-readme && verb
```
### Running tests
Running and reviewing unit tests is a great way to get familiarized with a library and its API. You can install dependencies and run tests with the following command:
```sh
$ npm install && npm test
```
### Author
**Jon Schlinkert**
* [github/jonschlinkert](https://github.com/jonschlinkert)
* [twitter/jonschlinkert](https://twitter.com/jonschlinkert)
### License
Copyright © 2017, [Jon Schlinkert](https://github.com/jonschlinkert).
Released under the [MIT License](LICENSE).
***
_This file was generated by [verb-generate-readme](https://github.com/verbose/verb-generate-readme), v0.6.0, on June 25, 2017._
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