is-reference

Utility for determining whether an AST node is a reference.

foo is a reference in these cases:

1console.log(foo);
2var foo;
3function foo() {}
4function bar(foo) {}
5export { foo as x };

foo is not a reference in these cases:

1var obj = { foo: 1 };
2console.log(obj.foo);
3export { x as foo };

In all cases, foo is an Identifier node, but the two kinds must be treated differently for the purposes of scope analysis etc. (The examples are non-exhaustive.)

Installation

1npm install is-reference

Usage

Example using Acorn and estree-walker:

1import { parse } from 'acorn';
2import { walk } from 'estree-walker';
3import is_reference from 'is-reference';
4
5const identifiers = [];
6const references = [];
7
8const ast = parse(`var a = b.c;`);
9
10walk(ast, {
11	enter(node, parent) {
12		if (node.type === 'Identifier') identifiers.push(node);
13		if (is_reference(node, parent)) references.push(node);
14	}
15});
16
17identifiers.forEach(node => console.log(node.name)); // a, b, c
18references.forEach(node => console.log(node.name)); // a, b

License

MIT