JS Utils 🔧

Collection of generic javascript utilities curated by the Rainbow Cafe~

• Promises
  • delay
    • delay.fallback
  • assert
    • assert.defined
  • never

Promises

delay

Creates a delayed promise for the given amount of seconds and given promises. This can be useful for allowing spinners / loading skeletons to exist for a bit rather then quickly popping in and out.

import { delay } from '@ribbon-studios/js-utils';

const promise = delay(); // Returns a promise with the preset delay
const promise = delay(1000); // Returns a promise with the given delay
const promise = delay(Promise.resolve('hello')); // Returns the original promise with the preset delay
const promise = delay(Promise.resolve('hello'), 1000); // Returns the original promise with the given delay

delay.fallback

This overrides the default delay value

import { delay } from '@ribbon-studios/js-utils';

const promise = delay(); // Returns a promise with a delay of 500ms
delay.fallback(100);
const promise = delay(); // Returns a promise with a delay of 100ms

assert

On its own assert isn't overly useful just because of how type assertion works.

import { assert } from '@ribbon-studios/js-utils';

export async function example() {
  const promise: Promise<string | undefined> = Promise.resolve('hello');
  // Run an assertion on the promises response
  const assertedPromise: Promise<string | undefined> = assert(promise, (value) => typeof value !== 'undefined');
  // Unfortunately our response is still considered undefined because we can't forward the assertion
}

assert.defined

Ensures the promise result is defined.

import { assert } from '@ribbon-studios/js-utils';

export async function example() {
  const promise: Promise<string | undefined> = Promise.resolve('hello');

  // Run an assertion on the promises response
  const assertedPromise: Promise<string> = assert.defined(promise);
  // Our promise is no longer considered undefined!

  // You can also pass a message to throw!
  const assertedPromise: Promise<string> = assert.defined(promise, 'Expected our thing to exist!');
}

never

Creates a promise that never resolves. Primary use-case for this is testing loading states.

In the event a promise is passed it will log a warning in the console as a reminder not to leave it in.

import { never } from '@ribbon-studios/js-utils';

const promise = never(); // Returns a promise that never resolves
const promise = never(Promise.resolve('hello')); // Returns a promise that never resolves

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