Function findReferences

src/javascript/references.ts:47–169

(
  node: Node,
  {
    globals = defaultGlobals,
    filterReference = (identifier: Identifier) => !globals.has(identifier.name),
    filterDeclaration = () => true
  }: {
    globals?: Set<string>;
    filterReference?: (identifier: Identifier) => any;
    filterDeclaration?: (identifier: {name: string}) => any;
  } = {}
)

}

export function findReferences(
  node: Node,
  {
    globals = defaultGlobals,
    filterReference = (identifier: Identifier) => !globals.has(identifier.name),
    filterDeclaration = () => true
  }: {
    globals?: Set<string>;
    filterReference?: (identifier: Identifier) => any;
    filterDeclaration?: (identifier: {name: string}) => any;
  } = {}
): Identifier[] {
  const locals = new Map<Node, Set<string>>();
  const references: Identifier[] = [];

  function hasLocal(node: Node, name: string): boolean {
    const l = locals.get(node);
    return l ? l.has(name) : false;
  }

  function declareLocal(node: Node, id: {name: string}): void {
    if (!filterDeclaration(id)) return;
    const l = locals.get(node);
    if (l) l.add(id.name);
    else locals.set(node, new Set([id.name]));
  }

  function declareClass(node: Class) {
    if (node.id) declareLocal(node, node.id);
  }

  function declareFunction(node: FunctionNode) {
    node.params.forEach((param) => declarePattern(param, node));
    if (node.id) declareLocal(node, node.id);
    if (node.type !== "ArrowFunctionExpression") declareLocal(node, {name: "arguments"});
  }

  function declareCatchClause(node: CatchClause) {
    if (node.param) declarePattern(node.param, node);
  }

  function declarePattern(node: Pattern, parent: Node) {
    switch (node.type) {
      case "Identifier":
        declareLocal(parent, node);
        break;
      case "ObjectPattern":
        node.properties.forEach((node) => declarePattern(node.type === "Property" ? node.value : node, parent));
        break;
      case "ArrayPattern":
        node.elements.forEach((node) => node && declarePattern(node, parent));
        break;
      case "RestElement":
        declarePattern(node.argument, parent);
        break;
      case "AssignmentPattern":
        declarePattern(node.left, parent);
        break;