Discover gists

How to test a React hooks which is binding a global window/document event(s):

This is an easy approach for testing DOM events in hooks/components without actually emmitting/triggering any "fake" events, which is much easier:

In the tests file, create a dummy React component and call the hook. if the hook is returning something, then assign it to a varaible which should be defined from outside the component so it will be available for the tests cases.

	import {isString} from 'utility/types';

	export const VERSION = 1; // current version of persisted data. if code change breaks persisted data, verison number should be bumped.
	export const STORAGE_KEY_PREFIX = 'amdocs/catalog';

	/**
	* checks arguments are as expected
	* @param {string} keyName
	* @param {string} type
	* @returns boolean

	-- Functions to create and draw histograms with PostgreSQL.
	-- psql> select * from show_histogram((select histogram(length(email), 0, 32, 6) FROM auth_user limit 100));
	-- bucket \| range \| count \| bar \| cumbar \| cumsum \| cumpct
	-- --------+-------------------------------------+-------+--------------------------------+--------------------------------+--------+------------------------
	-- 0 \| [0,5.33333333333333) \| 1 \| \| \| 1 \| 0.00273224043715846995
	-- 1 \| [5.33333333333333,10.6666666666667) \| 5 \| = \| \| 6 \| 0.01639344262295081967
	-- 2 \| [10.6666666666667,16) \| 149 \| ============================== \| ============= \| 155 \| 0.42349726775956284153
	-- 3 \| [16,21.3333333333333) \| 145 \| =========

	const addFrameConsciousEvent = (obj, event, handler) => { //adapted from: https://developer.mozilla.org/en-US/docs/Web/Events/resize#Example
	let isRunning = false;

	const handlerWrapper = (e)=> {
	if (!isRunning){
	isRunning = true;
	requestAnimationFrame(()=>{ //throttling so only execute when the browser is ready to re-render
	isRunning = false;
	handler(e);
	})

	(function (doc, w) {
	"use strict";

	var readyCallbacks = [],
	docLoadEv = "DOMContentLoaded",
	ready = (document.readyState === "complete");

	function registerForReadyEvent(fn) {

	if (ready) { //already ready, execute immediately

	/**
	* accepts n methods in sequence as arguments and returns a promise that is resolved
	* once all methods finish.
	* any argument may be an array of methods instead of a method itself. in this case, the array methods
	* will be run in parallel
	* any of the passed in methods may return a promise or any other type
	*
	* the results of the previous methods is handed over to the next method
	*
	* the last parameter may be an object containing one or both: {context, data}

	describe("root context", function(){

	before(function(){
	console.log("before: root");
	});

	beforeEach(function(){
	console.log("beforeEach: root");
	});

	/**
	*
	* !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
	* !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
	*
	* SEE MY venter NPM PACKAGE - https://www.npmjs.org/package/venter
	* OR REPOSITORY ON GITHUB - https://github.com/yoavniran/node-venter
	*
	* !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
	* !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

	body {
	content: linear-gradient(transparent, transparent);
	}