Remove any common leading whitespace from every line in 'text'

dedent.js

/**
 * Remove any common leading whitespace from every line in `text`
 * Ported from http://hg.python.org/cpython/file/2.7/Lib/textwrap.py 
 * @param text
 * @return {*}
 */
var dedent = function(text){
    var leadingWhitespaceRE = /(^[ \t]*)(?:[^ \t\n])/;
    var margin = null;
    var i;
    text = text.replace(/^[ \t]+$/m, '');

    var lines = text.split('\n');
    for(i = 0; i < lines.length; i++){
        var line = lines[i];
        if(leadingWhitespaceRE.exec(line)){
            var indent = RegExp.$1;
            if(margin == null){
                margin = indent;
            } else if(indent.match(new RegExp("^"+margin))){
                // Current line more deeply indented than previous winner:
                // no change (previous winner is still on top).

            } else if(margin.match(new RegExp("^"+indent))){
                // Current line consistent with and no deeper than previous winner:
                // it's the new winner.
                margin = indent;
            } else {
                // Current line and previous winner have no common whitespace:
                // there is no margin
                margin = "";
                break;
            }
        }
    }
    if(margin) {
        for(i = 0; i < lines.length; i++){
            lines[i] = lines[i].replace(new RegExp('^' + margin), '');
        }
        text = lines.join('\n');
    }
    return text;
};