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# API Documentation
*Please use only this documented API when working with the parser. Methods not documented here are subject to change at any point.*
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- [`parser` function](#parser-function) * [`parser.atword([props])`](#parseratwordprops) * [`parser.colon([props])`](#parsercolonprops) * [`parser.comma([props])`](#parsercommaprops) * [`parser.comment([props])`](#parsercommentprops) * [`parser.func([props])`](#parserfuncprops) * [`parser.number([props])`](#parsernumberprops) * [`parser.operator([props])`](#parseroperatorprops) * [`parser.paren([props])`](#parserparenprops) * [`parser.string([props])`](#parserstringprops) * [`parser.value([props])`](#parservalueprops) * [`parser.word([props])`](#parserwordprops) * [`parser.unicodeRange([props])`](#parserunicoderangeprops) - [Node types](#node-types) * [`node.type`](#nodetype) * [`node.parent`](#nodeparent) * [`node.toString()`, `String(node)`, or `'' + node`](#nodetostring-stringnode-or---node) * [`node.next()` & `node.prev()`](#nodenext--nodeprev) * [`node.replaceWith(node)`](#nodereplacewithnode) * [`node.remove()`](#noderemove) * [`node.clone()`](#nodeclone) * [`node.raws`](#noderaws) * [`node.source`](#nodesource) * [`node.sourceIndex`](#nodesourceindex) - [Container types](#container-types) * [`container.nodes`](#containernodes) * [`container.first` & `container.last`](#containerfirst--containerlast) * [`container.at(index)`](#containeratindex) * [`container.index(node)`](#containerindexnode) * [`container.length`](#containerlength) * [`container.each(callback)`](#containereachcallback) * [`container.walk(callback)`](#containerwalkcallback) * [`container.walk` proxies](#containerwalk-proxies) * [`container.prepend(node)` & `container.append(node)`](#containerprependnode--containerappendnode) * [`container.insertBefore(old, new)` & `container.insertAfter(old, new)`](#containerinsertbeforeold-new--containerinsertafterold-new) * [`container.removeChild(node)`](#containerremovechildnode) * [`container.removeAll()` or `container.empty()`](#containerremoveall-or-containerempty) - [Root nodes`](#root-nodes) - [Value nodes](#value-nodes)
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## `parser` function
This is the module's main entry point, and returns a `new Parser`.
```js let parser = require('postcss-values-parser');
let ast = parser(source) // tokenizes the source string .parse(); // parses the tokens and returns an AST ```
### `parser.atword([props])`
Creates a new AtWord value.
```js parser.atword({ value: '@foo' }); // → @foo ```
Arguments:
* `props (object)`: The new node's properties.
### `parser.colon([props])`
Creates a new colon Node.
```js parser.colon({ value: ':' }); // → : ```
Arguments:
* `props (object)`: The new node's properties. If no properties are specified, the default value of `:` will be used. It's not recommended to deviate from this.
### `parser.comma([props])`
Creates a new comma Node.
```js parser.comma({ value: ',' }); // → , ```
Arguments:
* `props (object)`: The new node's properties. If no properties are specified, the default value of `,` will be used. It's not recommended to deviate from this.
### `parser.comment([props])`
Creates a new comment.
```js parser.comment({ value: 'Affirmative, Dave. I read you.' }); // → /* Affirmative, Dave. I read you. */ ``` ```js parser.comment({ value: 'Affirmative, Dave. I read you.', inline: true }); // → // Affirmative, Dave. I read you. ```
Arguments:
* `props (object)`: The new node's properties.
### `parser.func([props])`
Creates a new function value Container node.
```js let func = parser.func({ value: 'calc' });
func.append(parser.paren()); func.append(parser.paren({ value: ')' }));
func.toString(); // → calc() ```
Arguments:
* `props (object)`: The new node's properties.
### `parser.number([props])`
Creates a new number Node.
```js parser.number({ value: 10, unit: 'px' }); // → 10px ```
Arguments:
* `props (object)`: The new node's properties.
### `parser.operator([props])`
Creates a new operator Node.
```js parser.operator({ value: '+' }); // → + ```
Arguments:
* `props (object)`: The new node's properties.
### `parser.paren([props])`
Creates a new parenthesis Node.
```js parser.paren(); // → (
parser.paren({ value: ')' }); // → ) ```
Arguments:
* `props (object)`: The new node's properties. If no value is specified, the default value of `(` will be used.
### `parser.string([props])`
Creates a new string node.
```js parser.string(); // → (empty)
parser.string({ value: 'hello', quote: '"' }); // → "hello" ```
Arguments:
* `props (object)`: The new node's properties. Note: If no `quote` property is specified, the default value of `'` will be used.
### `parser.value([props])`
Creates a new value Node. This node acts as the container for all values within the Root node, but can be created for convenience.
### `parser.word([props])`
Creates a new word Node. A `Word` is anything that doesn't fall into one of the other node types.
```js let word = parser.word({ value: '#fff' }); // → #fff
word.isHex; // → true
word.isColor; // → true ```
Arguments:
* `props (object)`: The new node's properties.
### `parser.unicodeRange([props])`
Creates a new unicode range Node.
```js parser.unicodeRange({ value: 'U+26' }); // → U+26 ```
Arguments:
* `props (object)`: The new node's properties. ## Node types
### `node.type`
A string representation of the node type. It can be one of the following; `atword`, `colon`, `comma`, `comment`, `func`, `number`, `operator`, `paren`, `string`, `unicoderange`, `value`, `word`.
```js parser.word({ value: '#fff' }).type; // → 'word' ```
### `node.parent`
Returns the parent node.
```js root.nodes[0].parent === root; ```
### `node.toString()`, `String(node)`, or `'' + node`
Returns a string representation of the node.
```js let color = parser.word({ value: '#fff' }); console.log(String(color)); // → #fff ```
### `node.next()` & `node.prev()`
Returns the next/previous child of the parent node.
```js let next = func.next(); if (next && next.type !== 'paren') { throw new Error('Unclosed function parenthesis!'); } ```
### `node.replaceWith(node)`
Replace a node with another.
```js let ast = parser('#fff').parse(); let word = ast.first.first; let atword = parser.atword({ value: '@purple' });
word.replaceWith(atword); ```
Arguments:
* `node`: The node to substitute the original with.
### `node.remove()`
Removes the node from its parent node.
```js if (node.type === 'word') { node.remove(); } ```
### `node.clone()`
Returns a copy of a node, detached from any parent containers that the original might have had.
```js let word = parser.word({ value: '#fff' }); let cloned = word.clone();
cloned.value = '#fff'; String(cloned); // → #000
String(word); // → #fff ```
### `node.raws`
Extra whitespaces around the node will be assigned to `node.raws.before` and `node.raws.after`. Spaces in this context have no semantic meaning, but may be useful for inspection:
```css 1px solid black ```
Any space following a node/segement is assigned to the next node's `raws.before` property, unless the node with the trailing space is the only node in the set.
```js let source = 'calc(something about mary)'; let ast = parser(source).parse(); let func = ast.first.first;
let something = func.first.next(); let about = something.next();
something.raws.after; // → (empty)
about.raws.before; // → ' ' ```
Additionally, any space remaining after the last node in a set will be assigned to the last non-symbol child's `raws.after` property. For example:
```js let source = 'calc(something )'; let ast = parser(source).parse(); let func = ast.first.first;
let something = func.first.next(); something.raws.after; // → ' ' ```
### `node.source`
An object describing the node's start/end, line/column source position.
Within the following CSS, the `.bar` class node ...
```css .foo, .bar {} ```
... will contain the following `source` object.
```js source: { start: { line: 2, column: 3 }, end: { line: 2, column: 6 } } ```
### `node.sourceIndex`
The zero-based index of the node within the original source string.
Within the following CSS, the `.baz` class node will have a `sourceIndex` of `12`.
```css .foo, .bar, .baz {} ```
## Container types
The `root`, `node`, and `pseudo` nodes have some helper methods for working with their children.
### `container.nodes`
An array of the container's children.
```js // Input: h1 h2 nodes.at(0).nodes.length // → 3 nodes.at(0).nodes[0].value // → 'h1' nodes.at(0).nodes[1].value // → ' ' ```
### `container.first` & `container.last`
The first/last child of the container.
```js node.first === node.nodes[0]; node.last === node.nodes[node.nodes.length - 1]; ```
### `container.at(index)`
Returns the node at position `index`.
```js node.at(0) === node.first; node.at(0) === node.nodes[0]; ```
Arguments:
* `index`: The index of the node to return.
### `container.index(node)`
Return the index of the node within its container.
```js node.index(node.nodes[2]) // → 2 ```
Arguments:
* `node`: A node within the current container.
### `container.length`
Proxy to the length of the container's nodes.
```js container.length === container.nodes.length ```
### `container.each(callback)`
Iterate the container's immediate children, calling `callback` for each child. You may return `false` within the callback to break the iteration.
```js let className; nodes.each(function (node, index) { if (node.type === 'class') { className = node.value; return false; } }); ```
Note that unlike `Array#forEach()`, this iterator is safe to use whilst adding or removing nodes from the container.
Arguments:
* `callback (function)`: A function to call for each node, which receives `node` and `index` arguments.
### `container.walk(callback)`
Like `container#each`, but will also iterate child nodes as long as they are `container` types.
```js nodes.walk(function (node, index) { // all nodes }); ```
Arguments:
* `callback (function)`: A function to call for each node, which receives `node` and `index` arguments.
This iterator is safe to use whilst mutating `container.nodes`, like `container#each`.
### `container.walk` proxies
The container class provides proxy methods for iterating over types of nodes, so that it is easier to write modules that target specific nodes. Those methods are:
* `container.walkAtWords` * `container.walkColons` * `container.walkCommas` * `container.walkComments` * `container.walkFunctionNodes` * `container.walkNumberNodes` * `container.walkOperators` * `container.walkParenthesis` * `container.walkStringNodes` * `container.walkUnicodeRanges` * `container.walkWords`
### `container.prepend(node)` & `container.append(node)`
Add a node to the start/end of the container. Note that doing so will set the parent property of the node to this container.
```js let color = parser.word({ value: '#fff' }); node.append(color); ```
Arguments:
* `node`: The node to add.
### `container.insertBefore(old, new)` & `container.insertAfter(old, new)`
Add a node before or after an existing node in a container:
```js nodes.walk(function (node) { if (node.type !== 'word') { let colon = parser.colon(); node.parent.insertAfter(node, colon); } }); ```
Arguments:
* `old`: The existing node in the container. * `new`: The new node to add before/after the existing node.
### `container.removeChild(node)`
Remove the node from the container. Note that you can also use `node.remove()` if you would like to remove just a single node.
```js node.length // → 2 node.remove(word) node.length // → 1; word.parent // undefined ```
Arguments:
* `node`: The node to remove.
### `container.removeAll()` or `container.empty()`
Remove all children from the container.
```js node.removeAll(); node.length // → 0 ```
## Root nodes`
A root node represents the top-level Container for Value nodes. Indeed, all a root's `toString()` method does is join its node children with a ','. Other than this, it has no special functionality and acts like a container.
## Value nodes
A Value node represents a single compound node. For example, this node string `1px solid black`, is represented as three distinct nodes. It has no special functionality of its own.
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