Javascript - kill white space in front of string
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I making some server reguests and the server reply me with a string that has a lot of spaces in front of the string. the string is USERNAME EXIST

I know how to use this:

    String.prototype.killWhiteSpace = function() {
    return this.replace(/\s/g, '');};

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

but the first the first answer me USERNAMEEXISTS and the second on " USERNAME EXIST"(with one space in front of the string).
Is there any way to kill all white spaces before and after the string?