falsyPromiseOrThrow

Returns a function that passes through falsy data or throws an error.

Available since v1.0.0

Import

import { falsyPromiseOrThrow } from '@helpers4/promise';

Signature

falsyPromiseOrThrow<T>(error: string): function

Parameters

Parameter	Type	Description
error	string	The error message to throw if data is truthy

Returns

function — A function that returns the data if falsy, or throws

Examples

Pass through falsy values

Returns the value if falsy, throws otherwise.

Promise.resolve(null).then(falsyPromiseOrThrow('Expected falsy'))
// => null

Throw on truthy values

Throws an error when the value is truthy.

Promise.resolve('oops').then(falsyPromiseOrThrow('Should be empty'))
// throws Error('Should be empty')

Source

View source on GitHub