How can I remove trailing certain blocks of whitespaces from a string in javascript?

Question

I need to adjust a string like so:

Cases where things should be adjusted:

Case a: "        ", becomes ""
Case b: "z       ", becomes "z"
Case c: "        z", becomes "z"

Cases where things shouldn't be adjusted:

~~Case d: " z ", stays the same~~

Case e: "zzz zz          zzz", stays the same

How can I achieve this in javascript?

And you may want to look through [all these other questions](http://stackoverflow.com/search?q=javascript+trim) on the topic. — Evan Davis, Nov 15 '13 at 00:40

hwnd · Accepted Answer · 2013-11-15T01:39:21.700

3

You can use String.trim() for this case. It removes the leading and trailing whitespace from a string. Many modern browsers support this method, which allows you to rewrite the above much shorter.

mystring = mystring.trim()

For browsers that do not support String.trim(), create your own method using a regular expression.

if (!String.prototype.trim) {
  String.prototype.trim = function() {
        return this.replace(/^\s+|\s+$/g, '');
  }
}

Alternatively, for most cases using it directly will perform the same.

mystring.replace(/^\s+|\s+$/g, '')

See live demo

edited Nov 15 '13 at 01:39

answered Nov 15 '13 at 00:32

hwnd

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This will not satisfy the Case d: – Leonardo Barbosa Nov 15 '13 at 00:34
Sorry let's forget about case d.! This is working nicely however, it removes spaces in between my words, which I don't wnat. Any single space I'd like preserved. I.E 'I am a cool person" – williamsandonz Nov 15 '13 at 00:39

Oriol · Answer 2 · 2013-11-15T00:45:50.743

3

You should use the ES5 .trim() method:

"        ".trim(); // "";
"z       ".trim(); // "z";
"       z".trim(); // "z";
"   z    ".trim(); // "z";
"zzz zz          zzz".trim(); // "zzz zz          zzz";

For compatibility with old browsers, you can add the following at the beginning of your script:

if (!String.prototype.trim) {
  String.prototype.trim = function () {
    return this.replace(/^\s+|\s+$/g, '');
  };
}

edited Nov 15 '13 at 00:45

answered Nov 15 '13 at 00:34

Oriol

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This fails the totally weird preceding/trailing combo example, `' z '`. – Evan Davis Nov 15 '13 at 00:35

score 3 · Answer 3 · edited May 23 '17 at 10:26

3

Inspired by Xander, try this, match all but variable e:

return s.replace(/^(\s+$|\w{1}\s+$|\s+\w{1}$|\s+\w{1}\s+$)/i, "Bingo");

And here is the Demo, hope this can help you :P

edited May 23 '17 at 10:26

Community

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answered Nov 15 '13 at 01:12

Santino_Wu

53
6

score 1 · Answer 4 · answered Nov 15 '13 at 00:46

Its enough for you to use trim function; but string.trim(); wont work in all browsers...

Try this:

String.prototype.trim=function(){return this.replace(/^\s+|\s+$/g, '');};

String.prototype.ltrim=function(){return this.replace(/^\s+/,'');};

String.prototype.rtrim=function(){return this.replace(/\s+$/,'');};

String.prototype.fulltrim=function(){return this.replace(/(?:(?:^|\n)\s+|\s+(?:$|\n))/g,'').replace(/\s+/g,' ');};

Since new Browsers (IE9+) have trim() already implemented, you should only implement trim() if it is not already available on the Prototype-Object (overriding it is a huge performance hit). This is generally recommended when extending Native Objects! Note that the added property is enumerable unless you use ES5 Object.defineProperty!

if (!String.prototype.trim) {
   //code for trim
}

You could have said your answer is a perfect duplicate of [Pradeep Kumar Mishra](http://stackoverflow.com/users/22710/pradeep-kumar-mishra)'s [one](http://stackoverflow.com/a/498995/1529630). — Oriol, Nov 15 '13 at 00:54

How can I remove trailing certain blocks of whitespaces from a string in javascript?

4 Answers4