A previous tutorial showed you how to create a JavaScript Map instance from an existing object. This time we’re doing it the other way around: transforming a JavaScript map into a plain object. {{outline}} Create a JavaScript Object From a Map Modern JavaScript engines ship with the Object.fromEntries( …

The ECMAScript 2015 specification introduced a Map class. A Map instance provides convenient methods around key-value-pairs. Objects in JavaScript are key-value-pairs as well. Yet, you can’t pass an existing object to the map constructor. This tutorial shows you how to create a JavaScript map from an existing object. {{outline} …

In a recent project, we needed to calculate differences between data points. Each data point represented an amount of money. The difference between the two data points should always be a positive number in context with prices going up or down. This tutorial shows you how to always retrieve a …

Sometimes you want to pick a random item from a JavaScript array. For example, when picking a winner from a list of participants. Or when highlighting one of your product’s great features. This tutorial shows you how to grab a random array item in JavaScript. {{outline}} Get a Random …

Leaving a loop early is a common practice in programming. Stopping or breaking out of an Array#forEach iteration in JavaScript is only possible by throwing an exception. Also, the Mozilla Developer Network states “when you need to stop forEach, it’s the wrong tool.” This tutorial points you to …

JavaScript introduced the for…of loops with ECMAScript 2015. The for loop provides a convenient way of iterating over a collection of items. A downside of a for…of loop: by default, it doesn’t give you the item’s index. Yet, you can conveniently work around this shortcoming and …

Sometimes you need to break out of a loop in JavaScript. For example, you may want to stop iterating through an array of items as soon as you find a specific element. TL;DR: use break to exit a loop in JavaScript. This tutorial shows you how to terminate the …

Sometimes you want to ensure a given value is actually a string. For example, you may want to confirm a name property to be a string value. This tutorial shows you how to detect whether a given value is a string in JavaScript. {{outline}} Determine If a Given Value Is …