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), :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
