@bitty/falsy

Falsy helper functions and types for TypeScript.

• 📦 Distributions in ESM, CommonJS, UMD and UMD minified formats.

• ⚡ Lightweight:

  • Weighs less than 0.2KB (min + gzip).
  • Tree-shakeable.
  • Side-effects free.

• 🔋 Bateries included:

  • No dependencies.
  • Its not based on newer browser's APIs or es2015+ features.

• 🏷 Safe:

  • JSDocs and type declarations for IDEs and editor's autocomplete/intellisense.
  • Made with TypeScript as strict as possible.
  • Unit tests with AVA.

Installation

This library is published in the NPM registry and can be installed using any compatible package manager.

npm install @bitty/falsy --save

# For Yarn, use the command below.
yarn add @bitty/falsy

Installation from CDN

This module has a UMD bundle available through JSDelivr and Unpkg CDNs.

<!-- For UNPKG use the code below. -->
<script src="https://unpkg.com/@bitty/falsy"></script>

<!-- For JSDelivr use the code below. -->
<script src="https://cdn.jsdelivr.net/npm/@bitty/falsy"></script>

<script>
  // UMD module is exposed through the "isFalsy" global function.
  console.log(isFalsy);
  //=> "[Function: isFalsy]"

  console.log(isFalsy(null));
  //=> true
</script>

Getting Stated

This module default exports isFalsy, which is a predicate function that checks if value is falsy.

import isFalsy from '@bitty/pipe';

isFalsy();
isFalsy(null);
isFalsy(undefined);
isFalsy(0);
isFalsy(-0);
isFalsy(0n);
isFalsy(NaN);
isFalsy('');
isFalsy(false);
//=> true

isFalsy('Not empty.');
//=> false

We also exports NonFalsy and Falsy types.

• Falsy is simply an union of false, void, '', 0, 0n, null and undefined, types.

  import { Falsy } from '@bitty/falsy';
  
  let falsy: Falsy;
  falsy = false;
  falsy = undefined as void;
  falsy = '';
  falsy = 0;
  falsy = 0n;
  falsy = null;
  falsy = undefined;
  
  falsy = 1;
  //=> throws "Type '1' is not assignable to type 'Falsy'.".

• NonFalsy<T> is a type helper that removes falsy types.

  import { NonFalsy } from '@bitty/falsy';
  
  type Value = 0 | 1 | 2;
  
  const value: NonFalsy<Value> = 0;
  //=> throws "Type '0' is not assignable to type '1 | 2'.".

License

Released under MIT License.