is-map

Is this value a JS Map? This module works cross-realm/iframe, and despite ES6 @@toStringTag.

Usage no npm install needed!

<script type="module">
  import isMap from 'https://cdn.skypack.dev/is-map';
</script>

README

is-map

Is this value a JS Map? This module works cross-realm/iframe, and despite ES6 @@toStringTag.

Example

var isMap = require('is-map');
assert(!isMap(function () {}));
assert(!isMap(null));
assert(!isMap(function* () { yield 42; return Infinity; });
assert(!isMap(Symbol('foo')));
assert(!isMap(1n));
assert(!isMap(Object(1n)));

assert(!isMap(new Set()));
assert(!isMap(new WeakSet()));
assert(!isMap(new WeakMap()));

assert(isMap(new Map()));

class MyMap extends Map {}
assert(isMap(new MyMap()));

Tests

Simply clone the repo, npm install, and run npm test