Trim string in JavaScript?

Question

How do I trim a string in JavaScript? That is, how do I remove all whitespace from the beginning and the end of the string in JavaScript?

Answer 1

You can do it using the plain JavaScript:

function trimString(str, maxLen) {
if (str.length <= maxLen) {
return str;
}
var trimmed = str.substr(0, maxLen);
return trimmed.substr(0, trimmed.lastIndexOf(' ')) + '…';
}

// Let's test it

sentenceOne = "too short";
sentencetwo = "more than the max length";

console.log(trimString(sentenceOne, 15));
console.log(trimString(sentencetwo, 15));

Answer 2

All browsers since IE9+ have trim() method for strings:

" \n test \n ".trim(); // returns "test" here

For those browsers who does not support trim(), you can use this polyfill from MDN:

if (!String.prototype.trim) {
    (function() {
        // Make sure we trim BOM and NBSP
        var rtrim = /^[\s\uFEFF\xA0]+|[\s\uFEFF\xA0]+$/g;
        String.prototype.trim = function() {
            return this.replace(rtrim, '');
        };
    })();
}

---

That said, if using jQuery, $.trim(str) is also available and handles undefined/null.

---

See 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,' ');};

Answer 3

If you are using jQuery, use the jQuery.trim() function. For example:

if( jQuery.trim(StringVariable) == '')

Answer 4

Trim code from angular js project

var trim = (function() {

  // if a reference is a `String`.
  function isString(value){
       return typeof value == 'string';
  } 

  // native trim is way faster: http://jsperf.com/angular-trim-test
  // but IE doesn't have it... :-(
  // TODO: we should move this into IE/ES5 polyfill

  if (!String.prototype.trim) {
    return function(value) {
      return isString(value) ? 
         value.replace(/^\s*/, '').replace(/\s*$/, '') : value;
    };
  }

  return function(value) {
    return isString(value) ? value.trim() : value;
  };

})();

and call it as trim(" hello ")

Answer 5

I have a lib that uses trim. so solved it by using the following code.

String.prototype.trim = String.prototype.trim || function(){ return jQuery.trim(this); };

Answer 6

For IE9+ and other browsers

function trim(text) {
    return (text == null) ? '' : ''.trim.call(text);
}