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Better loops in JavaScript

Kartik Malik on December 16, 2018

In this post, we will take a look at forms of for loop, array methods using which you can make your code simpler, more readable. These loops / me...

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JavaScript Joel • Dec 17 '18

Great article! I noticed some minor bugs:

// This:
arr.reduce((accumulator, currentValue) => (acc += curr), 0)

// Should be:
arr.reduce((acc, curr) => (acc + curr), 0)

You can change += to just be + also.

Same goes for:

// This:
arr.reduce((acc, curr) => (acc *= curr), 1)

// Can be:
arr.reduce((acc, curr) => (acc * curr), 1)

Cheers!

Kartik Malik • Dec 17 '18

Good catch :D thank you very much :)

Niels Bom • Dec 17 '18

Nice article!

If people are interested to read more on this style of programming in JS, it's called "functional programming". See this article for an introduction: dev.to/leandrotk_/functional-progr...

A really nice library for doing functional-style programming with JS: ramdajs

Hamm 🐘 • Dec 19 '18

Nice article. Thanks, Kartik. By the way, there is a little note to mention. It's better to use (for in) for objects and (for of) for arrays. Because (for in) has been optimized for Objects and not arrays.

Kartik Malik • Dec 23 '18

Oh cool, I didn't know that. Thanks for sharing :)

Summer Kiflain • Dec 17 '18

Nice article.

//sum of array elements
arr.reduce((accumulator, currentValue) => (acc += curr), 0)

should be:

//sum of array elements
arr.reduce((accumulator, currentValue) => (accumulator += currentValue), 0)

Kartik Malik • Dec 17 '18

Changed it. Thank you :)

Justin Gross • Dec 16 '18

Awesome write up! I'm glad you mentioned the less known ones as well like some and every. An additional note on the "for of" and forEach regarding accessing the index of an element would be nice. If you're interested in continuing to write about working with Arrays, the spread, rest, destructuring, Array.from and using asynchronous calls within loops would be another welcome write up!

Kartik Malik • Dec 17 '18

Yes these are interesting ideas will write about them soon :).

Juan Manuel Menendez Hernandez • Dec 20 '18

// checking if at least one of them is 18 or above
arr.some(val => val >= 18)

should be:

// checking if at least one of them is 18 or above
friends.some(val => val >= 18)

Good article, but next time you need to check the examples in the console men, you can do it better ;)

Kartik Malik • Dec 23 '18

Hehe thanks. Did run the examples on console, changed the names later though hence the issue. Will be careful next time :)

Daniel Mayovsky • May 15 '19

I should have known about array.every() earlier than today. Would've saved me time and brains

Kartik Malik • Dec 17 '18

Thanks for the link it's a nice read to get into performant code :).