join.js - Direct port of Python std posixpath.join. (Thanks Mr. Peterson!)

join.js

// src: http://stackoverflow.com/a/646643
// Add `startsWith` and `endsWith` to the String prototype.
if (typeof String.prototype.startsWith != 'function') {
    String.prototype.startsWith = function (str){
        return this.slice(0, str.length) == str;
    };
}

if (typeof String.prototype.endsWith != 'function') {
    String.prototype.endsWith = function (str){
        return this.slice(-str.length) == str;
    };
}


function path_join(a) {
    /* Direct port of Python std posixpath.join.
    src: https://hg.python.org/cpython/file/v2.7.3/Lib/posixpath.py:60
    */
    var path = a;
    for(var i=1; i<arguments.length; i++) {
        var b = arguments[i];
        if(b.startsWith('/')) {
            path = b;
        } else if (path == '' || path.endsWith('/')) {
            path = path.concat(b);
        } else {
            path = path.concat('/' + b);
        }
    }
    return path;
}