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:

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