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Anthony Humphreys
Anthony Humphreys

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If you've ever worked with a slow moving API that you just can't work around, you've probably written something along these lines already. I thought it would be handy to have this as a hook, to drop into loading components and not have to rewrite the same piece of logic umpteen times.

There are definitely better UX patterns than this, and I am in no way advocating this as a good practice for loading behaviour, but sometimes you can't avoid unsavoury bits of UI like this.

const text = useProgressiveLoading([3, 10, 15], ['Loading your profile is taking a litle longer than normal, please wait',
    'Still loading, please wait a while longer...',
    'Still loading your profile, thank you for your patience...']);

return (

The hook takes two parameters, the first is an array of times in seconds, the second is an array of strings. The principle is really simple, the hook creates a timeout for each timing passed, and will update the text value each time the timeout fires. The two arrays must be 'balanced' in terms of length, or the hook will throw an error.

import { useEffect, useState } from 'react';

export const useProgressiveLoading: Function = (
  timings: number[] = [5, 15, 30],
  strings: string[] = [
    'Still loading, please wait...',
    'Still loading, please wait a while longer...',
    'Still loading, thank you for your patience...',
): string => {
  if (timings.length !== strings.length) {
    throw new Error(
      `You passed ${timings.length} times and ${strings.length} - there should be the same number of each.`
  const [text, setText] = useState<string>('');
  const [timers, setTimers] = useState<number[]>([]);

  useEffect(() => {
    timings.forEach((delay: number, index: number) => {
      const timer: number = window.setTimeout(
        () => setText(strings[index]),
        delay * 1000
      setTimers(oldTimers => [...oldTimers, timer]);
    return () => {
      timers.forEach(timer => window.clearTimeout(timer));
  }, [timings, strings]);

  return text;

That's all there is to this one, its pretty simple!

You can install this from npm or check out the repo on GitHub

As always, suggestions, improvements etc all welcome!

This post was for day 4 of my #100DaysOfCode challenge. Follow me on Twitter for more.

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