| ESQuery is a library for querying the AST output by Esprima for patterns of syntax using a CSS style selector system. Check out the demo: |
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| [demo](https://estools.github.io/esquery/) |
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| The following selectors are supported: |
| * AST node type: `ForStatement` |
| * [wildcard](http://dev.w3.org/csswg/selectors4/#universal-selector): `*` |
| * [attribute existence](http://dev.w3.org/csswg/selectors4/#attribute-selectors): `[attr]` |
| * [attribute value](http://dev.w3.org/csswg/selectors4/#attribute-selectors): `[attr="foo"]` or `[attr=123]` |
| * attribute regex: `[attr=/foo.*/]` or (with flags) `[attr=/foo.*/is]` |
| * attribute conditions: `[attr!="foo"]`, `[attr>2]`, `[attr<3]`, `[attr>=2]`, or `[attr<=3]` |
| * nested attribute: `[attr.level2="foo"]` |
| * field: `FunctionDeclaration > Identifier.id` |
| * [First](http://dev.w3.org/csswg/selectors4/#the-first-child-pseudo) or [last](http://dev.w3.org/csswg/selectors4/#the-last-child-pseudo) child: `:first-child` or `:last-child` |
| * [nth-child](http://dev.w3.org/csswg/selectors4/#the-nth-child-pseudo) (no ax+b support): `:nth-child(2)` |
| * [nth-last-child](http://dev.w3.org/csswg/selectors4/#the-nth-last-child-pseudo) (no ax+b support): `:nth-last-child(1)` |
| * [descendant](http://dev.w3.org/csswg/selectors4/#descendant-combinators): `ancestor descendant` |
| * [child](http://dev.w3.org/csswg/selectors4/#child-combinators): `parent > child` |
| * [following sibling](http://dev.w3.org/csswg/selectors4/#general-sibling-combinators): `node ~ sibling` |
| * [adjacent sibling](http://dev.w3.org/csswg/selectors4/#adjacent-sibling-combinators): `node + adjacent` |
| * [negation](http://dev.w3.org/csswg/selectors4/#negation-pseudo): `:not(ForStatement)` |
| * [has](https://drafts.csswg.org/selectors-4/#has-pseudo): `:has(ForStatement)` |
| * [matches-any](http://dev.w3.org/csswg/selectors4/#matches): `:matches([attr] > :first-child, :last-child)` |
| * [subject indicator](http://dev.w3.org/csswg/selectors4/#subject): `!IfStatement > [name="foo"]` |
| * class of AST node: `:statement`, `:expression`, `:declaration`, `:function`, or `:pattern` |
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| [](https://travis-ci.org/estools/esquery) |
