DEV Community

Cover image for Killer JavaScript One Liners
Shshank
Shshank

Posted on

Killer JavaScript One Liners

#javascript #webdev #productivity #programming

Some useful JavaScript One-Liners

After a good response from the community, I decided to post some few more JavaScript one liners, that might help you a lot. I have posted a link to my previous article of Some useful JavaScript One Liners

Clear All Cookies 

const clearCookies = document.cookie.split(';').forEach((cookie) => (document.cookie = cookie.replace(/^ +/, '').replace(/=.*/, `=;expires=${new Date(0).toUTCString()};path=/`)));
Enter fullscreen mode Exit fullscreen mode

Reverse a String

You can reverse a string in one line using split, join and reverse methods.

const strReverse = str => str.split('').reverse().join('');
strReverse('Shshank');
// knahshS
Enter fullscreen mode Exit fullscreen mode

Generate a Random Hex

This method generates a random hex code using Math.random() and padEnd().

const hexClr = () => '#' + Math.floor(Math.random() * 0xffffff).toString(16).padEnd(6, '0');
console.log(hexClr());
Enter fullscreen mode Exit fullscreen mode

Capitalise a String

Javascript doesn't have an inbuilt capitalise function, so we can use the following code of the purpose.

let str = 'follow Shshank for amazing posts';
let capStr = str.replace(/\w\S*/g, (w) => (w.replace(/^\w/, (c) => c.toUpperCase())));
console.log(capStr);
Enter fullscreen mode Exit fullscreen mode

Copy to Clipboard

Easily copy any text to clipboard using navigator.clipboard.writeText.

const copy = (text) => navigator.clipboard.writeText(text);
copy('Shshank');
Enter fullscreen mode Exit fullscreen mode

Hope you like this post. If you find this post useful, please like and share with fellow developers. Follow me for more such posts.

Thank you.

Top comments (17)

Collapse
 
frankwisniewski profile image
Frank Wisniewski •

seen 1000 times and wrong 1000 times...

const str = 'Hello 😊 World';
const reversedStr = str.split('').reverse().join('');
console.log(reversedStr); // 'dlroW �� olleH'
Enter fullscreen mode Exit fullscreen mode
Collapse
 
ecyrbe profile image
ecyrbe •

You should then post the right one :

const str = 'Hello 😊 World';
const reversedStr = [...str].reverse().join('');
console.log(reversedStr); // 'dlroW 😊 olleH'
Enter fullscreen mode Exit fullscreen mode
Collapse
 
frankwisniewski profile image
Frank Wisniewski •

You too ....

Thread Thread
 
ecyrbe profile image
ecyrbe •

You made a critique without even trying to help. That was my point.
If you have knowledge, you should share it.

Thanks Luke for taking the time to add a fool proof version.

Thread Thread
 
frankwisniewski profile image
Frank Wisniewski •

this has been chewed through here so many times, a simple search is enough... dev.to/ianfelix/how-to-invert-a-st...

 
adam_cyclones profile image
Adam Crockett 🌀 •

You could also hard code the string backwards 😉

const string = "olleh"
Enter fullscreen mode Exit fullscreen mode

That's the efficiency of build time.

Nice one Luke

Thread Thread
 
jankapunkt profile image
Jan Küster •

Luke you should make this comment a new article do we can bookmark it 🙃

Thread Thread
 
adam_cyclones profile image
Adam Crockett 🌀 •

Oh man an article on hard coding strings where could that lead 🤪

Thread Thread
 
bias profile image
Tobias Nickel •

at least it does not lead to a configuration or environment variable called empty_string.

Thread Thread
 
adam_cyclones profile image
Adam Crockett 🌀 •

I don't know what that is 👍

Collapse
 
joolsmcfly profile image
Julien Dephix • • Edited

Clear all cookies is more of a tiny program than a one-liner ;)

To capitalise a string you could use the same technique as to reverse a string.

const upper = s.split("").map(n => n.toUpperCase()).join('');
Enter fullscreen mode Exit fullscreen mode

I find it easier to read / understand than two replace.
Hope this helps.

Collapse
 
frankwisniewski profile image
Frank Wisniewski • • Edited

you have to understand the task...

s='this is a mistake';
const upper = s.split("").map(n => n.toUpperCase()).join('');
console.log(upper === s.toUpperCase()) // true
Enter fullscreen mode Exit fullscreen mode
Collapse
 
joolsmcfly profile image
Julien Dephix •

Ha, my bad! I read too quickly.

I guess I should not be reading code on my phone at 11pm. 😓

Collapse
 
jonrandy profile image
Jon Randy 🎖️ • • Edited

Your random hex function has a number of problems. For starters, it will never return #ffffff. Also there are many other values it will never return as you're using padEnd instead of padStart

Collapse
 
jonrandy profile image
Jon Randy 🎖️ • • Edited 
const hexClr = ()=>'#'+(~~(Math.random()*8**8)).toString(16).padStart(6,0)
Enter fullscreen mode Exit fullscreen mode
Collapse
 
feba33 profile image
feba •

I personally use this to capitalize:
str[0].toUpperCase() + str.substr(1)

Collapse
 
prajyu profile image
prajyu •

How about adding another one liner
To remove duplicate values

const uniqueValues= (arr) => [...new Set(arr)];
Enter fullscreen mode Exit fullscreen mode
View full discussion (17 comments)

Read next

yanaiara profile image

Angular vs. ReactJS: Which One Should You Pick for Your Next Project?

Yanaiara Oliveira -

paharihacker profile image

React Performance Optimization Techniques: Memoization, Lazy Loading, and More

Rajesh Dhiman -

brunobrito profile image

2024's Git Survey is Live!

Bruno Brito -

preethi_p_gowda profile image

Future-Proofing Your Auth0 Integration: Moving from Rules and Hooks to Actions

Preethi Puttegowda -