Sputter is a CSS-like selector library that lets you query an arbitrary AST.

Sputter is a fork of ESQuery.

The following selectors are supported:

• AST node type: ForStatement
• wildcard: *
• attribute existence: [attr]
• attribute value: [attr="foo"] or [attr=123]
• attribute regex: [attr=/foo.*/]
• attribute conditons: [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)
• matches-any: :matches([attr] > :first-child, :last-child)
• subject indicator: !IfStatement > [name="foo"]
• eval for complex queries: :eval('node.type === "Foo"')

const ast = {
  type: "Foo",
  children: [
    {
      type: "Bar",
      value: 5,
    },
  ],
};

const sputter = require("sputter");

sputter.query(ast, "Foo > Bar[value=5]"); // [ { type: "Bar", value: 5 } ]

If your ast uses a key other than type to identify the type of a node, use .configure:

const ast = {
  kind: "Foo",
  children: [
    {
      kind: "Bar",
      value: 5,
    },
  ],
};

const sputter = require("sputter").configure({
  identifierKey: "kind",
});

sputter.query(ast, "Foo > Bar[value=5]"); // [ { kind: "Bar", value: 5 } ]