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Array Methods in JS - reverse()

Shubham Tiwari on August 16, 2022

Hello Guys today i will discuss reverse() array method in javascript reverse() method is used to reverse array elements Example - [1,2,3,4,5] Afte...
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joelbonetr profile image
JoelBonetR 🥇 •

Another one, this time with recursion:

/**
 * Reverses a string recursively
 * @param {string} str 
 * @returns {string}
 */
const reverseString = (str) => (str === '') ? '' : reverseString(str.substr(1)) + str.charAt(0);
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reverseString("hello") // olleh
reverseString('Hello, how are you?') // ?uoy era woh ,olleH
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😁

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Shubham Tiwari •

yeah but i only tried to discuss the inbuilt reverse() array method but this one liner implementation is also cool 😎

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JoelBonetR 🥇 •

Say no more:

const reverseStr = (str) => str.split("").reverse().join(""));
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😂😂

I'm loving this posts you do on your learning, following up to read more 😁

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shubhamtiwari909 profile image
Shubham Tiwari •

Yeah this one is also good but then I had to explain this also and i am trying to show everything as a beginners perspective so later they can simplify the code on their own and come with these type of one liner solutions 😉
Also I want to explain join and split in a separate posts that's why I didn't explained much about them in this blog 😂😂

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Frank Wisniewski •

seen 1000 times and wrong 1000 times...

const str = 'Hello 😊 World';
const reversedStr = str.split('').reverse().join('');
console.log(reversedStr); // 'dlroW �� olleH'
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joelbonetr profile image
JoelBonetR 🥇 • • Edited

Yes yees we know, that doesn't mean it's wrong. You don't need to deal with emojist most of the time and when you do, simply

const reverseStr = (str) => [...str].reverse().join('');
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There are multiple ways to deal with that 🤷🏻‍♀️

 
joelbonetr profile image
JoelBonetR 🥇 •

Agree. That's one thing I love of coding. Each little bloody thing you can pick like that, as you go further in detail it has tones of nuances, quirks, things to take care when defining, various ways to reach something similar and so on 😅

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shubhamtiwari909 profile image
Shubham Tiwari •

Hey Joel i wanted to ask something that is i am a fresher in web development and student also and i am impressed by your knowledge like you know everything in detail
I want to know from where and how can I improve my knowledge and skills like you and can become a better web developer

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joelbonetr profile image
JoelBonetR 🥇 • • Edited

Hey @shubhamtiwari909 actually you've people with tones of knowledge in the community and here in the post, like @lukeshiru who I found involved in many interesting comments and probably others which I may not recognize from other posts/discussions.

My workaround to learn more is to practice as much as I can and learn about stuff to bring new concepts to develop, new features to use and searching for different ways to reach the same to understand the differences so I can know when and where to use one or another.
I'm working as dev since just a decade ago so that's much less experience than many people here.

I learnt a lot in many projects having seasoned seniors next to me that were nice people and shared the knowledge and answering my child-ish questions (I'm always asking for the reason to be of the things and trying to understand the quirks and details) so I try to do the same in both my job and though this community.

In this specific case I knew almost nothing about this topic which is the emojis breaking when using split and I was itchy to know why does this happen so I began looking for information on the Internet, doing tests on my own, searching more with queries based on my test results... till I fulfilled my need for knowledge.

I knew nothing because the lack of experience. Never had to deal with that, and here's where the community adds an important value to the learning process.
Now, my future "me" will know this details if I need to use them.

If this was something more complex to remember I may write a post on that so anytime I need to remember the details of some concept I can come back to my own post and get what I need.

On the other hand some books helped me to understand some things in the past but not everyone likes to read as much.
I'm here because I prefer to read tech stuff than watching someone on YouTube explaining it. It's faster, I can easily copy-paste concepts, keywords to search later on and take my notes easily.

Also I wrote this post which I want to re-write (a second version of it) with the support of a Psychologist in a future.

Hope it helps you in any way :)

Also check the profiles of all that nice people that came to comment and follow the ones with posts that interests you or that may be of interest for your future "you"! 😁

Best regards

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shubhamtiwari909 profile image
Shubham Tiwari •

Thank you for telling me all of this
I asked this question because I had an interview today and the questions were asked about CSS but the questions were very tricky like which tags have an inline display property by default in HTML, What happens when we try to give width and height to "span" tag , etc and i wasn't able to answer those correctly because I didn't know about the in depth details and also these type of questions never came into my mind while learning that's why I asked how to get deep and detailed knowledge about web development
Same happens with Javascript also but i am practicing it practically and with multiple cases so i am getting little bit in good that

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joelbonetr profile image
JoelBonetR 🥇 • • Edited

Well, as I've previously said, the only way is to practice, reading, and writting posts about the topic are also beneficial

joelbonetr

Complete CSS Guide for beginners and not so beginners

JoelBonetR ・ Jun 23 '20 ・ 30 min read

You force yourself into a bit of I+D+i, looking at the details a bit in deep, to ensure you don't publish wrong information.

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shubhamtiwari909 profile image
Shubham Tiwari •

Thank you for guidance 😉

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Matthijs Wensveen •

One thing to note is that reverse() works in-place (aka destructively). This is important when you pass your array around to other functions or objects. For example:

function logNormal(arr) { console.log(arr); }
function logReverse(arr) { console.log(arr.reverse()); }
const a = [1, 2, 3]

logReverse(a); // [3, 2, 1]
logNormal(a); // [3, 2, 1] (whoops!)
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Shubham Tiwari •

Yeah it changes the original array