# is-reference | |
Utility for determining whether an AST node is a reference. | |
`foo` is a reference in these cases: | |
```js | |
console.log( foo ); | |
var foo; | |
function foo () {} | |
function bar ( foo ) {} | |
export { foo as x }; | |
``` | |
`foo` is *not* a reference in these cases: | |
```js | |
var obj = { foo: 1 }; | |
console.log( obj.foo ); | |
export { 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 | |
```bash | |
npm install is-reference | |
``` | |
## Usage | |
Example using [Acorn](https://github.com/ternjs/acorn) and [estree-walker](https://github.com/Rich-Harris/estree-walker): | |
```js | |
const { parse } = require( 'acorn' ); | |
const { walk } = require( 'estree-walker' ); | |
const isReference = require( 'is-reference' ); | |
const identifiers = []; | |
const references = []; | |
const ast = parse( `var a = b.c;` ); | |
walk( ast, { | |
enter ( node, parent ) { | |
if ( node.type === 'Identifier' ) identifiers.push( node ); | |
if ( isReference( node, parent ) ) references.push( node ); | |
} | |
}); | |
identifiers.forEach( node => console.log( node.name ) ); // a, b, c | |
references.forEach( node => console.log( node.name ) ); // a, b | |
``` | |
## License | |
MIT | |