JavaScript - Get the index of an array item in a for loop

JavaScript fundamental (ES6 Syntax): Exercise-268 with Solution

Write a JavaScript program to find the index of an array item in a for loop.

JavaScript's for...of loops provide an easy way to iterate over all kinds of iterables from arrays and stings to Map and Set objects. One supposed limitation over other options (e.g. Array.prototype.forEach()) is that you only get the value of each item in the iterable. But that is not necessarily the case, as you can easily leverage Array.prototype.entries() to get both the index and value of each array item:

Sample Solution:

JavaScript Code:

//#Source https://bit.ly/2neWfJ2
const colors = ['Red', 'Green', 'Black', 'White'];
for (let [index, item] of colors.entries()) {
 console.log(`${index}: ${item}`);

Sample Output:

0: Red
1: Green
2: Black
3: White


flowchart: Clamp a number within the inclusive range specified by the given boundary values a and b.

Live Demo:

See the Pen javascript-fundamental-exercise-268 by w3resource (@w3resource) on CodePen.

Improve this sample solution and post your code through Disqus

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JavaScript: Tips of the Day

Shorten an array using its length property

A great way of shortening an array is by redefining its length property.

let array = [0, 1, 2, 3, 4, 5, 6, 6, 8, 9]
array.length = 4
// Result: [0, 1, 2, 3]

Important to know though is that this is a destructive way of changing the array. This means you lose all the other values that used to be in the array.

Ref: https://bit.ly/2LBj213