Remove whitespaces inside a string in javascript

Question

I've read this question about javascript trim, with a regex answer.

Then I expect trim to remove the inner space between Hello and World.

function myFunction() {
    alert("Hello World ".trim());
}

EDITED

Why I expected that!?

Nonsense! Obviously trim doesn't remove inner spaces!, only leading and trailing ones, that's how trim works, then this was a very wrong question, my apologies.

trim removes whitespace from the beginning and end of a string — Manse, May 29 '12 at 13:42
Trim removes whitespace from *before* and *after* a string. `Hello World` is already "trimmed'. — gen_Eric, May 29 '12 at 13:42
related http://stackoverflow.com/questions/6623231/remove-all-white-spaces-from-text — Adriano, Jul 15 '14 at 11:38
Heh.. "obviously" trim will trim something but not from the "middle" ... you need a stripping instead of trimming.. a nice regex like someone already pointed out :-) — AlexD, Apr 06 '23 at 20:47

Henrik Andersson · Accepted Answer · 2018-08-10T14:10:47.863

374

For space-character removal use

"hello world".replace(/\s/g, "");

for all white space use the suggestion by Rocket in the comments below!

edited Aug 10 '18 at 14:10

answered May 29 '12 at 13:43

Henrik Andersson

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@RocketHazmat yes! the correct answer! though this might be slightly more efficient: str.replace(/\s+/g, '') – jackocnr Jan 08 '14 at 01:47
@RocketHazmat : what do u mean by other white spaces? '.replace(/ /g, '')' this will remove all white spaces right? – Pitchiah Natarajan Oct 13 '17 at 06:57
4

@PitchiahNatarajan `\s` will match spaces, tabs, and new lines. – gen_Eric Oct 15 '17 at 20:13

ArlanG · Answer 2 · 2023-04-10T20:49:37.117

49

You can use

"Hello World ".replace(/\s+/g, '');

trim() only removes trailing spaces on the string (first and last on the chain). In this case this regExp is faster because you can remove one or more spaces at the same time.

If you change the replacement empty string to '$', the difference becomes much clearer:

var string= '  Q  W E   R TY ';
console.log(string.replace(/\s/g, '$'));  // $$Q$$W$E$$$R$TY$
console.log(string.replace(/\s+/g, '#')); // #Q#W#E#R#TY#

Performance comparison - /\s+/g is faster. See here: http://jsperf.com/s-vs-s

Update

You can use too:

console.log(string.replaceAll(/\s/, '#')); // #Q#W#E#R#TY#

String.prototype.replaceAll()

edited Apr 10 '23 at 20:49

answered Apr 10 '20 at 12:25

ArlanG

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The [currently accepted answer](https://stackoverflow.com/a/10800402/215552) does the same thing. Please present some relevant tests indicating this is faster than that answer by anything more than nanoseconds. – Heretic Monkey Apr 10 '20 at 12:31
@HereticMonkey Updated! – ArlanG Apr 14 '20 at 14:01
2

Thank you for the example, made it crystal clear what the difference is doing. – Sigex Dec 09 '21 at 21:53
1

please update your answer with replaceAll – Antoine Weber Mar 31 '23 at 16:03

score 14 · Answer 3 · answered Oct 29 '21 at 07:11

The best way is to do it this way if you only want to replace the whitespaces:

let str = " H e l l o 1  5 9   ";
let onlyCharacters = str.replaceAll(" ", "");

// onlyCharacters = Hello159

I used str.replace(/\s/g, ""); a lot but it does not work in all the browsers for example it does not work in duckduckgo in android and also it does not work in android webview.

score 12 · Answer 4 · edited May 23 '17 at 11:54

12

Probably because you forgot to implement the solution in the accepted answer. That's the code that makes trim() work.

update

This answer only applies to older browsers. Newer browsers apparently support trim() natively.

edited May 23 '17 at 11:54

Community

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answered May 29 '12 at 13:42

John Conde

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Not necessarily, some browsers have it built in. :-P – gen_Eric May 29 '12 at 13:42
2

Its present in most modern browers now -> http://kangax.github.com/es5-compat-table/ – Manse May 29 '12 at 13:42

score 6 · Answer 5 · answered Aug 19 '19 at 21:41

You can use Strings replace method with a regular expression.

"Hello World ".replace(/ /g, "");

The replace() method returns a new string with some or all matches of a pattern replaced by a replacement. The pattern can be a string or a RegExp

RegExp

/ / - Regular expression matching spaces
g - Global flag; find all matches rather than stopping after the first match

const str = "H    e            l l       o  World! ".replace(/ /g, "");
document.getElementById("greeting").innerText = str;

<p id="greeting"><p>

Lars Flieger · Answer 6 · 2021-07-21T13:34:39.103

0

You could use a recursive solution:

function removeWhitespaces(string, i = 0, res = "") {
  if (i >= string.length)
    return res
  else
  if (string[i] == " ")
    return removeWhitespaces(string, i + 1, res)
  else
    return removeWhitespaces(string, i + 1, res += string[i])
}

console.log(removeWhitespaces(" Hello World,   how is it going ? "))

edited Jul 21 '21 at 13:34

answered Jul 21 '21 at 11:21

Lars Flieger

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score 0 · Answer 7 · answered Mar 30 '23 at 06:32

Precise answer to how to approach this depends on precise intention. To remove any and/or all white space characters you should use:

's t r i n g'.replace(\s+\g, '')

If the intention is to only remove specific types of whitespaces (ie. thin or hair spaces) they have to be listed explicitely like this:

's t r i n g'.replace(\ |\t \g, '')

However if the intention is to remove just plain spaces only, then performance wise the best solution is:

's t r i n g'.replace(' ', '')

Here is a benchmark comparing results. There is a slight performance variance amongst the regexp solutions, but its rather insignificant. However string based replace outperforms regexps in the linked benchamrk by about an order of magnitude of ops/s. (https://jsbench.me/drlfuphfhk/1)

Remove whitespaces inside a string in javascript

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