@xylabs/exists

Base functionality used throughout XY Labs TypeScript/JavaScript libraries

Install

Using npm:

npm install {{name}}

Using yarn:

yarn add {{name}}

Using pnpm:

pnpm add {{name}}

Using bun:

bun add {{name}}

License

See the LICENSE file for license rights and limitations (LGPL-3.0-only).

Reference

packages

exists

### .temp-typedoc

  ### functions

    ### <a id="exists"></a>exists

@xylabs/exists

function exists<T>(x?): x is NonNullable<T>;

Used to type narrow an object which is possibly null or undefined. Works well with functional Array methods. For example:

Type Parameters

T

T

Parameters

x?

T | null

The object which is potentially undefined or null

Returns

x is NonNullable<T>

False if the object is null/undefined, true otherwise

Example

const payloads: XyoPayload[] = boundWitness._payloads?.filter(exists) || []