esquery

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:

The following selectors are supported:

AST node type: ForStatement
wildcard: *
attribute existence: [attr]
attribute value: [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 or last child: :first-child or :last-child
nth-child (no ax+b support): :nth-child(2)
nth-last-child (no ax+b support): :nth-last-child(1)
descendant: ancestor descendant
child: parent > child
following sibling: node ~ sibling
adjacent sibling: node + adjacent
negation: :not(ForStatement)
has: :has(ForStatement)
matches-any: :matches([attr] > :first-child, :last-child)
subject indicator: !IfStatement > [name="foo"]
class of AST node: :statement, :expression, :declaration, :function, or :pattern

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