css-selector-parser

css-selector-parser

Version 3.0.5
Published 10 months ago
151 kB
No dependencies
MIT license

Install

npm i css-selector-parser

yarn add css-selector-parser

pnpm add css-selector-parser

Overview

Powerful and compliant CSS selector parser.

Variables

variable ast

const ast: AstFactory;

AST structure generators and matchers. For instance, ast.selector({rules: [...]}) creates AstSelector and ast.isSelector(...) checks if AstSelector was specified.
Example 1
// Represents CSS selector: ns|div#user-34.user.user-active[role="button"]:lang(en)::before > * const selector = ast.selector({ rules: [ ast.rule({ items: [ ast.tagName({name: 'div', namespace: ast.namespaceName({name: 'ns'})}), ast.id({name: 'user-34'}), ast.className({name: 'user'}), ast.className({name: 'user-active'}), ast.attribute({ name: 'role', operator: '=', value: ast.string({value: 'button'}) }), ast.pseudoClass({ name: 'lang', argument: ast.string({value: 'en'}) }), ast.pseudoElement({name: 'before'}) ], nestedRule: ast.rule({combinator: '>', items: [ast.wildcardTag()]}) }) ] }); console.log(ast.isSelector(selector)); // prints true console.log(ast.isRule(selector)); // prints false

Functions

function createParser

createParser: (options?: {
    syntax?: CssLevel | SyntaxDefinition;
    substitutes?: boolean;
    strict?: boolean;
}) => Parser;

Creates a parse function to be used later to parse CSS selectors.

function render

render: (entity: AstEntity) => string;

Renders CSS Selector AST back to a string.
Example 1
import {ast, render} from 'css-selector-parser';
const selector = ast.selector({ rules: [ ast.rule({ items: [ ast.tagName({name: 'a'}), ast.id({name: 'user-23'}), ast.className({name: 'user'}), ast.pseudoClass({name: 'visited'}), ast.pseudoElement({name: 'before'}) ] }) ] });
console.log(render(selector)); // a#user-23.user:visited::before

Interfaces

interface AstAttribute

interface AstAttribute {}

Attribute selector. Generated by .
Example 1
"[role='button' i]"

property caseSensitivityModifier

caseSensitivityModifier?: string;

Comparison case sensitivity modifier (i.e. "i" in case if "[role='button' i]").

property name

name: string;

Attribute name (i.e. "href" in case if "[href]").

property namespace

namespace?: AstNamespaceName | AstWildcardNamespace | AstNoNamespace;

Namespace according to https://drafts.csswg.org/selectors/#attrnmsp.

property operator

operator?: string;

Comparison operator (i.e. "|=" in case if "[role|=button]").

property type

type: 'Attribute';

property value

value?: AstString | AstSubstitution;

Comparison value (i.e. "button" in case if "[role=button]").

interface AstClassName

interface AstClassName {}

Class name condition. Matches by class attribute value. Generated by . https://developer.mozilla.org/en-US/docs/Web/CSS/ID_selectors
Example 1
".user"

property name

name: string;

ID name. I.e. .user -> "user".

property type

type: 'ClassName';

interface AstFactory

interface AstFactory extends AstFactoryBase {}

AST structure generators and matchers. For instance, ast.selector({rules: [...]}) creates AstSelector and ast.isSelector(...) checks if AstSelector was specified.
Example 1
// Represents CSS selector: ns|div#user-34.user.user-active[role="button"]:lang(en)::before > * const selector = ast.selector({ rules: [ ast.rule({ items: [ ast.tagName({name: 'div', namespace: ast.namespaceName({name: 'ns'})}), ast.id({name: 'user-34'}), ast.className({name: 'user'}), ast.className({name: 'user-active'}), ast.attribute({ name: 'role', operator: '=', value: ast.string({value: 'button'}) }), ast.pseudoClass({ name: 'lang', argument: ast.string({value: 'en'}) }), ast.pseudoElement({name: 'before'}) ], nestedRule: ast.rule({combinator: '>', items: [ast.wildcardTag()]}) }) ] }); console.log(ast.isSelector(selector)); // prints true console.log(ast.isRule(selector)); // prints false

interface AstFormula

interface AstFormula {}

Pseudo-class formula value. a is multiplier of n and b us added on top. Formula: an + b. For instance :nth-child(2n + 1) -> {type: 'AstPseudoClass'..., argument: {type: 'Formula', a: 2, b: 1}}. Generated by .
See Also
- https://developer.mozilla.org/en-US/docs/Web/CSS/:nth-child#functional_notation

property a

a: number;

Multiplier of n.

property b

b: number;

Constant added to a*n.

property type

type: 'Formula';

interface AstFormulaOfSelector

interface AstFormulaOfSelector {}

Pseudo-class formula of selector value. a is multiplier of n and b us added on top. Formula: an + b. Formula is followed by of keyword and then goes a CSS selector. For instance :nth-child(2n + 1 of div) -> {type: 'AstPseudoClass'..., argument: {type: 'FormulaOfSelector', a: 2, b: 1, selector: {type: 'Selector', rules: [{type: 'Rule', items: [{type: 'TagName', name: 'div'}]}]}}}. Generated by .
See Also
- https://developer.mozilla.org/en-US/docs/Web/CSS/:nth-child#functional_notation

property a

a: number;

Multiplier of n.

property b

b: number;

Constant added to a*n.

property selector

selector: AstRule;

Selector that goes after formula (i.e. "div -> span" in case of ":nth-child(2n + 1 of div > span)"

property type

type: 'FormulaOfSelector';

interface AstId

interface AstId {}

ID condition. Matches by id attribute value. Generated by . https://developer.mozilla.org/en-US/docs/Web/CSS/ID_selectors
Example 1
"#root"

property name

name: string;

ID name. I.e. #root -> "root".

property type

type: 'Id';

interface AstNamespaceName

interface AstNamespaceName {}

Named namespace declaration (i.e. ns|div). Generated by .
See Also
- https://drafts.csswg.org/css-namespaces-3/#css-qnames

property name

name: string;

Namespace name (i.e. "ns" in case of "ns|div"). "

property type

type: 'NamespaceName';

interface AstNoNamespace

interface AstNoNamespace {}

Explicit no-namespace declaration (i.e. |div). Generated by .
See Also
- https://drafts.csswg.org/css-namespaces-3/#css-qnames

property type

type: 'NoNamespace';

interface AstPseudoClass

interface AstPseudoClass {}

Pseudo-class selector. Generated by .
Example 1
":lang(en)"
See Also
- https://developer.mozilla.org/en-US/docs/Learn/CSS/Building_blocks/Selectors/Pseudo-classes_and_pseudo-elements

property argument

argument?:
    | AstSubstitution
    | AstSelector
    | AstString
    | AstFormula
    | AstFormulaOfSelector;

Pseudo-class value (i.e. "en" in case of ":lang(en)").

property name

name: string;

Pseudo-class name (i.e. "hover" in case of ":hover").

property type

type: 'PseudoClass';

interface AstPseudoElement

interface AstPseudoElement {}

Pseudo-class selector. Generated by .
Example 1
"::before"
See Also
- https://developer.mozilla.org/en-US/docs/Learn/CSS/Building_blocks/Selectors/Pseudo-classes_and_pseudo-elements

property argument

argument?: AstSubstitution | AstString | AstSelector;

Pseudo-element value (i.e. "foo" in case of "::part(foo)").

property name

name: string;

Pseudo-element name (i.e. "before" in case of "::before").

property type

type: 'PseudoElement';

interface AstRule

interface AstRule {}

A single CSS rule that contains match conditions. Can nest another rule with or without a combinator (i.e. "div > span"). Generated by .

property combinator

combinator?: string;

Rule combinator which was used to nest this rule (i.e. ">" in case of "div > span" if the current rule is "span").

property items

items: (
    | AstTagName
    | AstWildcardTag
    | AstId
    | AstClassName
    | AstAttribute
    | AstPseudoClass
    | AstPseudoElement
)[];

Items of a CSS rule. Can be tag, ids, class names, pseudo-classes and pseudo-elements.

property nestedRule

nestedRule?: AstRule;

Nested rule if specified (i.e. "div > span").

property type

type: 'Rule';

interface AstSelector

interface AstSelector {}

CSS Selector AST root. Contains list of CSS rules (separated by a comma in the input CSS selector string). Generated by .

property rules

rules: AstRule[];

List of CSS rules. Every rule contains conditions. Selector is considered matched once at least one rule matches.

property type

type: 'Selector';

interface AstString

interface AstString {}

String value. Can be used as attribute value of pseudo-class string value. For instance :lang(en) -> {type: 'AstPseudoClass'..., argument: {type: 'String', value: 'en'}}. Generated by .

property type

type: 'String';

property value

value: string;

The actual string value.

interface AstSubstitution

interface AstSubstitution {}

Substitution is not part of CSS spec, but rather a useful extension on top of CSS if you need to pass variables. Generated by .

property name

name: string;

Substitution name (i.e. "var" in case of "[role=$var]" or ":lang($var)").

property type

type: 'Substitution';

interface AstTagName

interface AstTagName {}

Named tag, i.e. "div". Part of CSS Qualified Names. Generated by .
See Also
- https://developer.mozilla.org/en-US/docs/Web/CSS/Type_selectors
- https://drafts.csswg.org/css-namespaces-3/#css-qnames

property name

name: string;

Tag name, i.e. "div".

property namespace

namespace?: AstNamespaceName | AstWildcardNamespace | AstNoNamespace;

Namespace according to https://www.w3.org/TR/css3-namespace/.

property type

type: 'TagName';

interface AstWildcardNamespace

interface AstWildcardNamespace {}

Wildcard namespace (universal selector): *. Generated by .
See Also
- https://developer.mozilla.org/en-US/docs/Web/CSS/Universal_selectors
- https://drafts.csswg.org/css-namespaces-3/#css-qnames

property type

type: 'WildcardNamespace';

interface AstWildcardTag

interface AstWildcardTag {}

Wildcard tag (universal selector): *. Generated by .
See Also
- https://developer.mozilla.org/en-US/docs/Web/CSS/Universal_selectors
- https://drafts.csswg.org/css-namespaces-3/#css-qnames

property namespace

namespace?: AstNamespaceName | AstWildcardNamespace | AstNoNamespace;

Namespace according to https://www.w3.org/TR/css3-namespace/.

property type

type: 'WildcardTag';

interface ParserError

interface ParserError extends Error {}

This error is thrown when parser encounters problems in CSS string. On top of the usual error, it has position property to indicate where in the input string the error happened.

property message

message: string;

property name

name: 'ParserError';

property position

position: number;

interface SyntaxDefinition

interface SyntaxDefinition {}

CSS Selector Syntax Definition can be used to define custom CSS selector parsing rules.

property attributes

attributes?:
    | {
          /**
           * Attribute comparison operator list.
           * @example ['=', '~=', '|=', '^=', '$=', '*=']
           * @see https://developer.mozilla.org/en-US/docs/Web/CSS/Attribute_selectors#syntax
           */
          operators?: string[];
          /**
           * How to handle unknown case sensitivity modifiers.
           * `accept` - still parse.
           * `reject` - throw an error.
           */
          unknownCaseSensitivityModifiers?: 'accept' | 'reject';
          /**
           * List of pre-defined case sensitivity modifiers.
           * @example ['i', 'I', 's', 'S']
           * @see https://developer.mozilla.org/en-US/docs/Web/CSS/Attribute_selectors#syntax
           */
          caseSensitivityModifiers?: string[];
      }
    | false;

CSS Attribute Selector.
Example 1
[href="#"]
See Also
- https://developer.mozilla.org/en-US/docs/Learn/CSS/Building_blocks/Selectors/Attribute_selectors

property baseSyntax

baseSyntax?: CssLevel;

When specified, syntax will be based on the specified predefined CSS standard. If not specified, syntax will be defined from scratch.

property classNames

classNames?: boolean;

CSS Class Names
Example 1
.element.highlighted
See Also
- https://developer.mozilla.org/en-US/docs/Learn/CSS/Building_blocks/Selectors/Type_Class_and_ID_Selectors

property combinators

combinators?: string[];

CSS selector rule nesting combinators.
Example 1
div.class > span
See Also
- https://developer.mozilla.org/en-US/docs/Learn/CSS/Building_blocks/Selectors/Combinators

property ids

ids?: boolean;

CSS IDs (yes, there can be multiple).
Example 1
#root#root
See Also
- https://developer.mozilla.org/en-US/docs/Learn/CSS/Building_blocks/Selectors/Type_Class_and_ID_Selectors

property namespace

namespace?:
    | {
          /**
           * Allows using wildcard (*).
           */
          wildcard?: boolean;
      }
    | boolean;

CSS3 Namespaces.
Example 1
ns|div
See Also
- https://www.w3.org/TR/css3-namespace/

property pseudoClasses

pseudoClasses?:
    | {
          /**
           * How to handle unknown pseudo-classes.
           * `accept` - still parse.
           * `reject` - throw an error.
           */
          unknown?: 'accept' | 'reject';
          /**
           * Predefined pseudo-classes.
           * @example {NoArgument: ['first-child'], Formula: ['nth-child'], String: ['dir'], Selector: ['not']}
           */
          definitions?: {
              [K in PseudoClassType]?: string[];
          };
      }
    | false;

CSS Pseudo-classes.
Example 1
:nth-child(2n+1)
See Also
- https://developer.mozilla.org/en-US/docs/Learn/CSS/Building_blocks/Selectors/Pseudo-classes_and_pseudo-elements

property pseudoElements

pseudoElements?:
    | {
          /**
           * How to handle unknown pseudo-elements.
           * `accept` - still parse.
           * `reject` - throw an error.
           */
          unknown?: 'accept' | 'reject';
          /**
           * In the past pseudo selements were defined starting with a single colon.
           * Later this notation changed to double colon.
           */
          notation?: 'singleColon' | 'doubleColon' | 'both';
          /**
           * List of predefined pseudo-elements. If string array is specified, the pseudo-elements are assumed to be
           * NoArgument.
           * @example ['before', 'after']
           * @example {NoArgument: ['before', 'after'], String: ['highlight'], Selector: ['slotted']}
           */
          definitions?:
              | string[]
              | {
                    [K in PseudoElementType]?: string[];
                };
      }
    | false;

CSS Pseudo-elements.
Example 1
::before
See Also
- https://developer.mozilla.org/en-US/docs/Learn/CSS/Building_blocks/Selectors/Pseudo-classes_and_pseudo-elements

property tag

tag?:
    | {
          /**
           * Allows using wildcard (*).
           */
          wildcard?: boolean;
      }
    | boolean;

CSS Tag (type).
Example 1
div
See Also
- https://developer.mozilla.org/en-US/docs/Learn/CSS/Building_blocks/Selectors/Type_Class_and_ID_Selectors

Type Aliases

type AstEntity

type AstEntity =
    | AstSelector
    | AstRule
    | AstTagName
    | AstWildcardTag
    | AstId
    | AstClassName
    | AstNamespaceName
    | AstWildcardNamespace
    | AstNoNamespace
    | AstSubstitution
    | AstString
    | AstFormula
    | AstFormulaOfSelector
    | AstPseudoClass
    | AstAttribute
    | AstPseudoElement;

One of CSS AST entity types.

type CssLevel

type CssLevel =
    | 'css1'
    | 'css2'
    | 'css3'
    | 'selectors-3'
    | 'selectors-4'
    | 'latest'
    | 'progressive';

type Parser

type Parser = (input: string) => AstSelector;

Parses CSS selector string and returns CSS selector AST.
Throws
{ParserError}

Package Files (5)

Dependencies (0)

No dependencies.

Dev Dependencies (19)

Peer Dependencies (0)

No peer dependencies.

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Updated 10 months ago.
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css-selector-parser

Install

Overview

Index

Variables

Functions

Interfaces

Type Aliases

Variables

variable ast

Example 1

Functions

function createParser

function render

Example 1

Interfaces

interface AstAttribute

Example 1

property caseSensitivityModifier

property name

property namespace

property operator

property type

property value

interface AstClassName

Example 1

property name

property type

interface AstFactory

Example 1

interface AstFormula

See Also

property a

property b

property type

interface AstFormulaOfSelector

See Also

property a

property b

property selector

property type

interface AstId

Example 1

property name

property type

interface AstNamespaceName

See Also

property name

property type

interface AstNoNamespace

See Also

property type

interface AstPseudoClass

Example 1

See Also

property argument

property name

property type

interface AstPseudoElement

Example 1

See Also

property argument

property name

property type

interface AstRule

property combinator

property items

property nestedRule

property type

interface AstSelector

property rules

property type

interface AstString

property type

property value

interface AstSubstitution

property name

property type

interface AstTagName

See Also