@zerodep/is-undefined

A simple, performant utility to determine if a value is a undefined.

Full documentation is available at the zerodep.app page.

Examples

All @zerodep packages support both ESM and CJS.

import { isUndefined } from '@zerodep/is-undefined';
// or
const { isUndefined } = require('@zerodep/is-undefined');

Positive Response

isUndefined(undefined); // true

Negative Response

isUndefined(['a', 'b', 'c']); // false
isUndefined(1000n); // false
isUndefined(true); // false
isUndefined(new Date()); // false
isUndefined(''); // false
isUndefined(new Error('message')); // false
isUndefined(3.14); // false
isUndefined(() => 'function'); // false
isUndefined(42); // false
isUndefined(
  new Map([
    ['a', 1],
    ['b', 2],
  ])
); // false
isUndefined(null); // false
isUndefined({ an: 'object' }); // false
isUndefined(new Promise(() => {})); // false
isUndefined(/[regex]+/gi); // false
isUndefined(new Set([1, 2, 3])); // false
isUndefined('a string'); // false
isUndefined(Symbol()); // false
isUndefined(new Int32Array(2)); // false