Class for creating AST nodes.
npm install snapdragon-node> Class for creating AST nodes.
Please consider following this project's author, Jon Schlinkert, and consider starring the project to show your :heart: and support.
Install with npm:
``sh`
$ npm install --save snapdragon-node
`js`
const Node = require('snapdragon-node');
// either pass on object with "type" and (optional) "val"
const node1 = new Node({type: 'star', val: '*'});
// or pass "val" (first) and "type" (second) as string
const node2 = new Node('*', 'star');
// both result in => Node { type: 'star', val: '*' }
With snapdragon v0.9.0 and higher, it's recommended that you use this.node() to create a new Node inside parser handlers (instead of doing new Node()).
Example usage inside a snapdragon parser handler function.
`js
const Node = require('snapdragon-node');
const Token = require('snapdragon-token');
// create a new AST node
const node = new Node({ type: 'star', value: '*' });
// convert a Lexer Token into an AST Node
const token = new Token({ type: 'star', value: '*' });
const node = new Node(token);
`
AST Nodes are represented as Node objects that implement the following interface:
`js`
interface Node {
type: string;
value: string | undefined
nodes: array | undefined
}
* type {string} - A string representing the node variant type. This property is often used for classifying the purpose or nature of the node, so that parsers or compilers can determine what to do with it.value
* {string|undefined} (optional) - In general, value should only be a string when node.nodes is undefined. This is not reinforced, but is considered good practice. Use a different property name to store arbitrary strings on the node when node.nodes is an array.nodes
* {array|undefined} (optional) - array of child nodes
A number of useful methods and non-enumerable properties are also exposed for adding, finding and removing child nodes, etc.
Continue reading the API documentation for more details.
Create a new AST Node with the given type and value, or an object to initialize with.
Params
* type {object|string}: Either an object to initialize with, or a string to be used as the node.type.value
* {string|boolean}: If the first argument is a string, the second argument may be a string value to set on node.value.clone
* {boolean}: When an object is passed as the first argument, pass true as the last argument to deep clone values before assigning them to the new node.returns
* {Object}: node instance
Example
`js`
console.log(new Node({ type: 'star', value: '*' }));
console.log(new Node('star', '*'));
// both result in => Node { type: 'star', value: '*' }
Return a clone of the node. Values that are arrays or plain objects are deeply cloned.
* returns {Object}: returns a clone of the node
Example
`js`
const node = new Node({type: 'star', value: '*'});
consle.log(node.clone() !== node);
//=> true
Return a string created from node.value and/or recursively visiting over node.nodes.
* returns {String}
Example
`js`
const node = new Node({type: 'star', value: '*'});
consle.log(node.stringify());
//=> '*'
Push a child node onto the node.nodes array.
Params
* node {Object}returns
* {Number}: Returns the length of node.nodes, like Array.push
Example
`js`
const foo = new Node({type: 'foo'});
const bar = new Node({type: 'bar'});
foo.push(bar);
Unshift a child node onto node.nodes, and set node as the parent on child.parent.
Params
* node {Object}returns
* {Number}: Returns the length of node.nodes
Example
`js`
const foo = new Node({type: 'foo'});
const bar = new Node({type: 'bar'});
foo.unshift(bar);
Pop a node from node.nodes.
* returns {Number}: Returns the popped node
Example
`js`
const 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 a node from node.nodes.
* returns {Object}: Returns the shifted node
Example
`js`
const 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 node from node.nodes.
Params
* node {Object}returns
* {Object}: Returns the removed node.
Example
`js`
node.remove(childNode);
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`
const child = node.find(1); //<= index of the node to get
const child = node.find('foo'); //<= node.type of a child node
const child = node.find(/^(foo|bar)$/); //<= regex to match node.type
const child = node.find(['foo', 'bar']); //<= array of node.type(s)
Returns true if node.nodes array contains the given node.
Params
* type {String}returns
* {Boolean}
Example
`js`
const foo = new Node({type: 'foo'});
const bar = new Node({type: 'bar'});
cosole.log(foo.has(bar)); // false
foo.push(bar);
cosole.log(foo.has(bar)); // true
Return true if the node.nodes has the given type.
Params
* type {String}returns
* {Boolean}
Example
`js
const foo = new Node({type: 'foo'});
const bar = new Node({type: 'bar'});
foo.push(bar);
cosole.log(foo.hasType('qux')); // false
cosole.log(foo.hasType(/^(qux|bar)$/)); // true
cosole.log(foo.hasType(['qux', 'bar'])); // true
`
Return true if the node is the given type.
Params
* type {String}returns
* {Boolean}
Example
`js`
const 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
Returns true if node.value 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`
const node = new Node({type: 'text'});
node.isEmpty(); //=> true
node.value = 'foo';
node.isEmpty(); //=> false
Returns true if the node has an ancestor node of the given type
Params
* type {String}returns
* {Boolean}
Example
`js`
const box = new Node({type: 'box'});
const marble = new Node({type: 'marble'});
box.push(marble);
marble.isInside('box'); //=> true
Get the siblings array, or null if it doesn't exist.
* returns {Array}
Example
`js
const foo = new Node({type: 'foo'});
const bar = new Node({type: 'bar'});
const baz = new Node({type: 'baz'});
foo.push(bar);
foo.push(baz);
console.log(bar.siblings.length) // 2
console.log(baz.siblings.length) // 2
`
Calculate the node's current index on node.parent.nodes, or -1 if the node does not have a parent, or is not on node.parent.nodes.
* returns {Number}
Example
`js
const foo = new Node({type: 'foo'});
const bar = new Node({type: 'bar'});
const baz = new Node({type: 'baz'});
const 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
`
Get the previous node from the siblings array or null.
* returns {Object}
Example
`js
const foo = new Node({type: 'foo'});
const bar = new Node({type: 'bar'});
const baz = new Node({type: 'baz'});
foo.push(bar);
foo.push(baz);
console.log(baz.prev.type) // 'bar'
`
Get the next element from the siblings array, or null if a next node does not exist.
* returns {Object}
Example
`js
const parent = new Node({type: 'root'});
const foo = new Node({type: 'foo'});
const bar = new Node({type: 'bar'});
const baz = new Node({type: 'baz'});
parent.push(foo);
parent.push(bar);
parent.push(baz);
console.log(foo.next.type) // 'bar'
console.log(bar.next.type) // 'baz'
`
Get the first child node from node.nodes.
* returns {Object}: The first node, or undefiend
Example
`js
const foo = new Node({type: 'foo'});
const bar = new Node({type: 'bar'});
const baz = new Node({type: 'baz'});
const qux = new Node({type: 'qux'});
foo.push(bar);
foo.push(baz);
foo.push(qux);
console.log(foo.first.type) // 'bar'
`
Get the last child node from node.nodes.
* returns {Object}: The last node, or undefiend
Example
`js
const foo = new Node({type: 'foo'});
const bar = new Node({type: 'bar'});
const baz = new Node({type: 'baz'});
const qux = new Node({type: 'qux'});
foo.push(bar);
foo.push(baz);
foo.push(qux);
console.log(foo.last.type) // 'qux'
`
Get the node.depth. The root node has a depth of 0. Add 1 to child nodes for each level of nesting.
* returns {Object}: The last node, or undefiend
Example
`js
const foo = new Node({type: 'foo'});
foo.push(bar);
console.log(foo.depth) // 1
console.log(bar.depth) // 2
`
Static method that returns true if the given value is a node.
Params
* node {Object}returns
* {Boolean}
Example
`js`
const Node = require('snapdragon-node');
const node = new Node({type: 'foo'});
console.log(Node.isNode(node)); //=> true
console.log(Node.isNode({})); //=> false
* node.isNode {boolean} - this value is set to true when a node is created. This can be useful in situationas as a fast alternative to using instanceof Node if you need to determine if a value is a node object.node.size
* {number} - the number of child nodes that have been pushed or unshifted onto node.nodes using the node's API. This is useful for determining if nodes were added to node.nodes without using node.push() or node.unshift() (for example: if (node.nodes && node.size !== node.nodes.length))node.parent
* {object} (instance of Node)
See the changelog.
Contributing
Pull requests and stars are always welcome. For bugs and feature requests, please create an issue.
Please read the contributing guide for advice on opening issues, pull requests, and coding standards.
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
Building docs
_(This project's readme.md is generated by verb, please don't edit the readme directly. Any changes to the readme must be made in the .verb.md readme template.)_
To generate the readme, run the following command:
`sh``
$ npm install -g verbose/verb#dev verb-generate-readme && verb
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* snapdragon-capture: Snapdragon plugin that adds a capture method to the parser instance. | homepage
* snapdragon-cheerio: Snapdragon plugin for converting a cheerio AST to a snapdragon AST. | homepage
* snapdragon-util: Utilities for the snapdragon parser/compiler. | homepage
* snapdragon: Easy-to-use plugin system for creating powerful, fast and versatile parsers and compilers, with built-in source-map… more | homepage
Jon Schlinkert
* GitHub Profile
* Twitter Profile
* LinkedIn Profile
Copyright © 2018, Jon Schlinkert.
Released under the MIT License.
*
_This file was generated by verb-generate-readme, v0.8.0, on November 24, 2018._