--- /dev/null
+# API Documentation
+
+*Please use only this documented API when working with the parser. Methods
+not documented here are subject to change at any point.*
+
+## `parser` function
+
+This is the module's main entry point.
+
+```js
+const parser = require('postcss-selector-parser');
+```
+
+### `parser([transform], [options])`
+
+Creates a new `processor` instance
+
+```js
+const processor = parser();
+
+// or, with optional transform function
+const transform = selectors => {
+ selectors.walkUniversals(selector => {
+ selector.remove();
+ });
+};
+
+const processor = parser(transform)
+
+// Example
+const result = processor.processSync('*.class');
+// => .class
+```
+
+[See processor documentation](#processor)
+
+Arguments:
+
+* `transform (function)`: Provide a function to work with the parsed AST.
+* `options (object)`: Provide default options for all calls on the returned `Processor`.
+
+### `parser.attribute([props])`
+
+Creates a new attribute selector.
+
+```js
+parser.attribute({attribute: 'href'});
+// => [href]
+```
+
+Arguments:
+
+* `props (object)`: The new node's properties.
+
+### `parser.className([props])`
+
+Creates a new class selector.
+
+```js
+parser.className({value: 'button'});
+// => .button
+```
+
+Arguments:
+
+* `props (object)`: The new node's properties.
+
+### `parser.combinator([props])`
+
+Creates a new selector combinator.
+
+```js
+parser.combinator({value: '+'});
+// => +
+```
+
+Arguments:
+
+* `props (object)`: The new node's properties.
+
+### `parser.comment([props])`
+
+Creates a new comment.
+
+```js
+parser.comment({value: '/* Affirmative, Dave. I read you. */'});
+// => /* Affirmative, Dave. I read you. */
+```
+
+Arguments:
+
+* `props (object)`: The new node's properties.
+
+### `parser.id([props])`
+
+Creates a new id selector.
+
+```js
+parser.id({value: 'search'});
+// => #search
+```
+
+Arguments:
+
+* `props (object)`: The new node's properties.
+
+### `parser.nesting([props])`
+
+Creates a new nesting selector.
+
+```js
+parser.nesting();
+// => &
+```
+
+Arguments:
+
+* `props (object)`: The new node's properties.
+
+### `parser.pseudo([props])`
+
+Creates a new pseudo selector.
+
+```js
+parser.pseudo({value: '::before'});
+// => ::before
+```
+
+Arguments:
+
+* `props (object)`: The new node's properties.
+
+### `parser.root([props])`
+
+Creates a new root node.
+
+```js
+parser.root();
+// => (empty)
+```
+
+Arguments:
+
+* `props (object)`: The new node's properties.
+
+### `parser.selector([props])`
+
+Creates a new selector node.
+
+```js
+parser.selector();
+// => (empty)
+```
+
+Arguments:
+
+* `props (object)`: The new node's properties.
+
+### `parser.string([props])`
+
+Creates a new string node.
+
+```js
+parser.string();
+// => (empty)
+```
+
+Arguments:
+
+* `props (object)`: The new node's properties.
+
+### `parser.tag([props])`
+
+Creates a new tag selector.
+
+```js
+parser.tag({value: 'button'});
+// => button
+```
+
+Arguments:
+
+* `props (object)`: The new node's properties.
+
+### `parser.universal([props])`
+
+Creates a new universal selector.
+
+```js
+parser.universal();
+// => *
+```
+
+Arguments:
+
+* `props (object)`: The new node's properties.
+
+## Node types
+
+### `node.type`
+
+A string representation of the selector type. It can be one of the following;
+`attribute`, `class`, `combinator`, `comment`, `id`, `nesting`, `pseudo`,
+`root`, `selector`, `string`, `tag`, or `universal`. Note that for convenience,
+these constants are exposed on the main `parser` as uppercased keys. So for
+example you can get `id` by querying `parser.ID`.
+
+```js
+parser.attribute({attribute: 'href'}).type;
+// => 'attribute'
+```
+
+### `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
+const id = parser.id({value: 'search'});
+console.log(String(id));
+// => #search
+```
+
+### `node.next()` & `node.prev()`
+
+Returns the next/previous child of the parent node.
+
+```js
+const next = id.next();
+if (next && next.type !== 'combinator') {
+ throw new Error('Qualified IDs are not allowed!');
+}
+```
+
+### `node.replaceWith(node)`
+
+Replace a node with another.
+
+```js
+const attr = selectors.first.first;
+const className = parser.className({value: 'test'});
+attr.replaceWith(className);
+```
+
+Arguments:
+
+* `node`: The node to substitute the original with.
+
+### `node.remove()`
+
+Removes the node from its parent node.
+
+```js
+if (node.type === 'id') {
+ node.remove();
+}
+```
+
+### `node.clone()`
+
+Returns a copy of a node, detached from any parent containers that the
+original might have had.
+
+```js
+const cloned = parser.id({value: 'search'});
+String(cloned);
+
+// => #search
+```
+
+### `node.spaces`
+
+Extra whitespaces around the node will be moved into `node.spaces.before` and
+`node.spaces.after`. So for example, these spaces will be moved as they have
+no semantic meaning:
+
+```css
+ h1 , h2 {}
+```
+
+However, *combinating* spaces will form a `combinator` node:
+
+```css
+h1 h2 {}
+```
+
+A `combinator` node may only have the `spaces` property set if the combinator
+value is a non-whitespace character, such as `+`, `~` or `>`. Otherwise, the
+combinator value will contain all of the spaces between selectors.
+
+### `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`, `selector`, 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
+selectors.at(0).nodes.length // => 3
+selectors.at(0).nodes[0].value // => 'h1'
+selectors.at(0).nodes[1].value // => ' '
+```
+
+### `container.first` & `container.last`
+
+The first/last child of the container.
+
+```js
+selector.first === selector.nodes[0];
+selector.last === selector.nodes[selector.nodes.length - 1];
+```
+
+### `container.at(index)`
+
+Returns the node at position `index`.
+
+```js
+selector.at(0) === selector.first;
+selector.at(0) === selector.nodes[0];
+```
+
+Arguments:
+
+* `index`: The index of the node to return.
+
+### `container.index(node)`
+
+Return the index of the node within its container.
+
+```js
+selector.index(selector.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` Array iterators
+
+The container class provides proxies to certain Array methods; these are:
+
+* `container.map === container.nodes.map`
+* `container.reduce === container.nodes.reduce`
+* `container.every === container.nodes.every`
+* `container.some === container.nodes.some`
+* `container.filter === container.nodes.filter`
+* `container.sort === container.nodes.sort`
+
+Note that these methods only work on a container's immediate children; recursive
+iteration is provided by `container.walk`.
+
+### `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;
+selectors.each((selector, index) => {
+ if (selector.type === 'class') {
+ className = selector.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
+selectors.walk((selector, 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 selectors. Those
+methods are:
+
+* `container.walkAttributes`
+* `container.walkClasses`
+* `container.walkCombinators`
+* `container.walkComments`
+* `container.walkIds`
+* `container.walkNesting`
+* `container.walkPseudos`
+* `container.walkTags`
+* `container.walkUniversals`
+
+### `container.split(callback)`
+
+This method allows you to split a group of nodes by returning `true` from
+a callback. It returns an array of arrays, where each inner array corresponds
+to the groups that you created via the callback.
+
+```js
+// (input) => h1 h2>>h3
+const list = selectors.first.split(selector => {
+ return selector.type === 'combinator';
+});
+
+// (node values) => [['h1', ' '], ['h2', '>>'], ['h3']]
+```
+
+Arguments:
+
+* `callback (function)`: A function to call for each node, which receives `node`
+ as an argument.
+
+### `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
+const id = parser.id({value: 'search'});
+selector.append(id);
+```
+
+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
+selectors.walk(selector => {
+ if (selector.type !== 'class') {
+ const className = parser.className({value: 'theme-name'});
+ selector.parent.insertAfter(selector, className);
+ }
+});
+```
+
+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
+selector.length // => 2
+selector.remove(id)
+selector.length // => 1;
+id.parent // undefined
+```
+
+Arguments:
+
+* `node`: The node to remove.
+
+### `container.removeAll()` or `container.empty()`
+
+Remove all children from the container.
+
+```js
+selector.removeAll();
+selector.length // => 0
+```
+
+## Root nodes
+
+A root node represents a comma separated list of selectors. Indeed, all
+a root's `toString()` method does is join its selector children with a ','.
+Other than this, it has no special functionality and acts like a container.
+
+### `root.trailingComma`
+
+This will be set to `true` if the input has a trailing comma, in order to
+support parsing of legacy CSS hacks.
+
+## Selector nodes
+
+A selector node represents a single compound selector. For example, this
+selector string `h1 h2 h3, [href] > p`, is represented as two selector nodes.
+It has no special functionality of its own.
+
+## Pseudo nodes
+
+A pseudo selector extends a container node; if it has any parameters of its
+own (such as `h1:not(h2, h3)`), they will be its children. Note that the pseudo
+`value` will always contain the colons preceding the pseudo identifier. This
+is so that both `:before` and `::before` are properly represented in the AST.
+
+## Attribute nodes
+
+### `attribute.quoted`
+
+Returns `true` if the attribute's value is wrapped in quotation marks, false if it is not.
+Remains `undefined` if there is no attribute value.
+
+```css
+[href=foo] /* false */
+[href='foo'] /* true */
+[href="foo"] /* true */
+[href] /* undefined */
+```
+
+### `attribute.qualifiedAttribute`
+
+Returns the attribute name qualified with the namespace if one is given.
+
+### `attribute.offsetOf(part)`
+
+ Returns the offset of the attribute part specified relative to the
+ start of the node of the output string. This is useful in raising
+ error messages about a specific part of the attribute, especially
+ in combination with `attribute.sourceIndex`.
+
+ Returns `-1` if the name is invalid or the value doesn't exist in this
+ attribute.
+
+ The legal values for `part` are:
+
+ * `"ns"` - alias for "namespace"
+ * `"namespace"` - the namespace if it exists.
+ * `"attribute"` - the attribute name
+ * `"attributeNS"` - the start of the attribute or its namespace
+ * `"operator"` - the match operator of the attribute
+ * `"value"` - The value (string or identifier)
+ * `"insensitive"` - the case insensitivity flag
+
+### `attribute.raws.unquoted`
+
+Returns the unquoted content of the attribute's value.
+Remains `undefined` if there is no attribute value.
+
+```css
+[href=foo] /* foo */
+[href='foo'] /* foo */
+[href="foo"] /* foo */
+[href] /* undefined */
+```
+
+### `attribute.spaces`
+
+Like `node.spaces` with the `before` and `after` values containing the spaces
+around the element, the parts of the attribute can also have spaces before
+and after them. The for each of `attribute`, `operator`, `value` and
+`insensitive` there is corresponding property of the same nam in
+`node.spaces` that has an optional `before` or `after` string containing only
+whitespace.
+
+Note that corresponding values in `attributes.raws.spaces` contain values
+including any comments. If set, these values will override the
+`attribute.spaces` value. Take care to remove them if changing
+`attribute.spaces`.
+
+### `attribute.raws`
+
+The raws object stores comments and other information necessary to re-render
+the node exactly as it was in the source.
+
+If a comment is embedded within the identifiers for the `namespace`, `attribute`
+or `value` then a property is placed in the raws for that value containing the full source of the propery including comments.
+
+If a comment is embedded within the space between parts of the attribute
+then the raw for that space is set accordingly.
+
+Setting an attribute's property `raws` value to be deleted.
+
+For now, changing the spaces required also updating or removing any of the
+raws values that override them.
+
+Example: `[ /*before*/ href /* after-attr */ = /* after-operator */ te/*inside-value*/st/* wow */ /*omg*/i/*bbq*/ /*whodoesthis*/]` would parse as:
+
+```js
+{
+ attribute: "href",
+ operatator: "=",
+ value: "test",
+ spaces: {
+ before: '',
+ after: '',
+ attribute: { before: ' ', after: ' ' },
+ operator: { after: ' ' },
+ value: { after: ' ' },
+ insensitive: { after: ' ' }
+ },
+ raws: {
+ spaces: {
+ attribute: { before: ' /*before*/ ', after: ' /* after-attr */ ' },
+ operator: { after: ' /* after-operator */ ' },
+ value: { after: '/* wow */ /*omg*/' },
+ insensitive: { after: '/*bbq*/ /*whodoesthis*/' }
+ },
+ unquoted: 'test',
+ value: 'te/*inside-value*/st'
+ }
+}
+```
+
+## `Processor`
+
+### `ProcessorOptions`
+
+* `lossless` - When `true`, whitespace is preserved. Defaults to `true`.
+* `updateSelector` - When `true`, if any processor methods are passed a postcss
+ `Rule` node instead of a string, then that Rule's selector is updated
+ with the results of the processing. Defaults to `true`.
+
+### `process|processSync(selectors, [options])`
+
+Processes the `selectors`, returning a string from the result of processing.
+
+Note: when the `updateSelector` option is set, the rule's selector
+will be updated with the resulting string.
+
+**Example:**
+
+```js
+const parser = require("postcss-selector-parser");
+const processor = parser();
+
+let result = processor.processSync(' .class');
+console.log(result);
+// => .class
+
+// Asynchronous operation
+let promise = processor.process(' .class').then(result => {
+ console.log(result)
+ // => .class
+});
+
+// To have the parser normalize whitespace values, utilize the options
+result = processor.processSync(' .class ', {lossless: false});
+console.log(result);
+// => .class
+
+// For better syntax errors, pass a PostCSS Rule node.
+const postcss = require('postcss');
+rule = postcss.rule({selector: ' #foo > a, .class '});
+processor.process(rule, {lossless: false, updateSelector: true}).then(result => {
+ console.log(result);
+ // => #foo>a,.class
+ console.log("rule:", rule.selector);
+ // => rule: #foo>a,.class
+})
+```
+
+Arguments:
+
+* `selectors (string|postcss.Rule)`: Either a selector string or a PostCSS Rule
+ node.
+* `[options] (object)`: Process options
+
+
+### `ast|astSync(selectors, [options])`
+
+Like `process()` and `processSync()` but after
+processing the `selectors` these methods return the `Root` node of the result
+instead of a string.
+
+Note: when the `updateSelector` option is set, the rule's selector
+will be updated with the resulting string.
+
+### `transform|transformSync(selectors, [options])`
+
+Like `process()` and `processSync()` but after
+processing the `selectors` these methods return the value returned by the
+processor callback.
+
+Note: when the `updateSelector` option is set, the rule's selector
+will be updated with the resulting string.
+
+### Error Handling Within Selector Processors
+
+The root node passed to the selector processor callback
+has a method `error(message, options)` that returns an
+error object. This method should always be used to raise
+errors relating to the syntax of selectors. The options
+to this method are passed to postcss's error constructor
+([documentation](http://api.postcss.org/Container.html#error)).
+
+#### Async Error Example
+
+```js
+let processor = (root) => {
+ return new Promise((resolve, reject) => {
+ root.walkClasses((classNode) => {
+ if (/^(.*)[-_]/.test(classNode.value)) {
+ let msg = "classes may not have underscores or dashes in them";
+ reject(root.error(msg, {
+ index: classNode.sourceIndex + RegExp.$1.length + 1,
+ word: classNode.value
+ }));
+ }
+ });
+ resolve();
+ });
+};
+
+const postcss = require("postcss");
+const parser = require("postcss-selector-parser");
+const selectorProcessor = parser(processor);
+const plugin = postcss.plugin('classValidator', (options) => {
+ return (root) => {
+ let promises = [];
+ root.walkRules(rule => {
+ promises.push(selectorProcessor.process(rule));
+ });
+ return Promise.all(promises);
+ };
+});
+postcss(plugin()).process(`
+.foo-bar {
+ color: red;
+}
+`.trim(), {from: 'test.css'}).catch((e) => console.error(e.toString()));
+
+// CssSyntaxError: classValidator: ./test.css:1:5: classes may not have underscores or dashes in them
+//
+// > 1 | .foo-bar {
+// | ^
+// 2 | color: red;
+// 3 | }
+```
+
+#### Synchronous Error Example
+
+```js
+let processor = (root) => {
+ root.walkClasses((classNode) => {
+ if (/.*[-_]/.test(classNode.value)) {
+ let msg = "classes may not have underscores or dashes in them";
+ throw root.error(msg, {
+ index: classNode.sourceIndex,
+ word: classNode.value
+ });
+ }
+ });
+};
+
+const postcss = require("postcss");
+const parser = require("postcss-selector-parser");
+const selectorProcessor = parser(processor);
+const plugin = postcss.plugin('classValidator', (options) => {
+ return (root) => {
+ root.walkRules(rule => {
+ selectorProcessor.processSync(rule);
+ });
+ };
+});
+postcss(plugin()).process(`
+.foo-bar {
+ color: red;
+}
+`.trim(), {from: 'test.css'}).catch((e) => console.error(e.toString()));
+
+// CssSyntaxError: classValidator: ./test.css:1:5: classes may not have underscores or dashes in them
+//
+// > 1 | .foo-bar {
+// | ^
+// 2 | color: red;
+// 3 | }
+```
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