Javascript Regular Expression for Removing all Spaces except for what between double quotes

Question

I have a String that I need to strip out all the spaces except for what between "". Here is the Regex that I am using to strip out spaces.

str.replace(/\s/g, "");

I cant seem to figure out how to get it to ignore spaces between quotes. Example

str = 'Here is my example "leave spaces here", ok im done'
Output = 'Hereismyexample"leave spaces here",okimdone'

Just a reminder: don't create a var called `String` because there's already a function/constructor with this name (use `string` instead) — Danilo Valente, Jan 26 '13 at 18:29
@MarkLinus how often you need to refer to the String cl... er, constructor? — John Dvorak, Jan 26 '13 at 18:30
Almost never. However, it's not a good practice to override native variables (unless when necessary and intentionally). Also, as I said, this is a reminder, not a rule — Danilo Valente, Jan 26 '13 at 18:34
@MarkLinus note that `var String` doesn't _overwrite_ native variables (that would be bad), it _shadows_ them (that's less bad). — John Dvorak, Jan 26 '13 at 18:35
I can't see the `var` keyword there. I've got your point, I'm just warning him about this issue — Danilo Valente, Jan 26 '13 at 18:37
@Jan: It overwrites them if this is in global scope. Fun experiment: Type `var String = 'foo';` on this page in the console and try to click on `add / show X more comments` :) — Felix Kling, Jan 26 '13 at 18:37
@FelixKling is right. In the global scope, `var String` equals to `window.String` — Danilo Valente, Jan 26 '13 at 18:40

Denys Séguret · Answer 1 · 2013-01-26T18:30:55.273

8

var output = input.split('"').map(function(v,i){
   return i%2 ? v : v.replace(/\s/g, "");
}).join('"');

Note that I renamed the variables because I can't write code with a variable whose name starts with an uppercase and especially when it's a standard constructor of the language. I'd suggest you stick with those guidelines when in doubt.

edited Jan 26 '13 at 18:30

answered Jan 26 '13 at 18:28

Denys Séguret

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"whose name starts with an uppercase or is a standard constructor of the language." -- doesn't the latter imply the former? – John Dvorak Jan 26 '13 at 18:32
@JanDvorak I mean that I don't like `Output` either. – Denys Séguret Jan 26 '13 at 18:33

nhahtdh · Accepted Answer · 2013-01-26T19:04:41.653

Another way to do it. This has the assumption that no escaping is allowed within double quoted part of the string (e.g. no "leave \" space \" here"), but can be easily modified to allow it.

str.replace(/([^"]+)|("[^"]+")/g, function($0, $1, $2) {
    if ($1) {
        return $1.replace(/\s/g, '');
    } else {
        return $2; 
    } 
});

Modified regex to allow escape of " within quoted string:

/([^"]+)|("(?:[^"\\]|\\.)+")/

score 4 · Answer 3 · edited May 23 '17 at 12:08

Rob, resurrecting this question because it had a simple solution that only required one replace call, not two. (Found your question while doing some research for a regex bounty quest.)

The regex is quite short:

"[^"]+"|( )

The left side of the alternation matches complete quoted strings. We will ignore these matches. The right side matches and captures spaces to Group 1, and we know they are the right spaced because they were not matched by the expression on the left.

Here is working code (see demo):

var subject = 'Here is my example "leave spaces here", ok im done';
var regex = /"[^"]+"|( )/g;
replaced = subject.replace(regex, function(m, group1) {
    if (group1 == "" ) return m;
    else return "";
});
document.write(replaced);

Reference

Javascript Regular Expression for Removing all Spaces except for what between double quotes

3 Answers3