[JavaScript]偶自己的JavaScript扩展库(一点一点完善中...)

所有的对内置对象扩展的方法都是以x(stands for 'extend')开头, 非扩展内置对象的方法按英文原意命名, 然后命名空间为wf(stands for wind fantasy)

Object.prototype.xattach = function (obj, nooverwrite) {
  for (var prop in obj) {
    // if the property exists and disallow the property to be overwritten, just skip
    if (typeof this[prop] != 'undefined' && nooverwrite) {
      continue;
    }
    this[prop] = obj[prop];
  }
  return this;
}
        
String.xattach({
  xrepeat: function (repeat, times) {
    return new Array(times+1).join(repeat);
  }
});
        
String.prototype.xattach( {
  xrepeat: function (times) {
    return String.xrepeat(this, times);
  }
});
        
Array.xattach({
  'xrange': function (start, stop, step) { // python-like range
    var value, range = [];
    if (arguments.length == 1) {
      stop = start;
      start = 0;
    }
    if (isNaN(stop) || isNaN(start)) {
      return null;
    }
    if (isNaN(step) || step == 0)
      step = start < stop ? 1 : -1;
    if (step > 0) {
      for (value = start; value < stop; value += step)
        range.push(value);
    } else {
      for (value = start; value > stop; value += step)
        range.push(value);
    }
    return range;
  }
});
        
Array.prototype.xattach({
  //        toString: function () { // better toString
  //          return ' [' + this.join(',') + '] ';
  //        },
  xcopy: function () { // shallow copy
    return this.slice();
  },
  // [1,2,3,4,5].xgroup(2) => [ [1,2], [2,3], [3,4], [4,5] ]
  xgroup: function (count) { // group all subsequences of which the length is count from this
    var i, targetlen = this.length - count + 1, target = [];
    for (i = 0; i < targetlen; ++i)
      target[i] = this.slice(i, i+count);
    return target;
  },
  // ['a', 'b', 'c']; xmap(null, parseInt, true, 16) => [10, 11, 12]
  // if you don't want to change array itsself and wanna get the return value, you
  // can do like this: arr.xcopy().xmap(null, parseInt, true, 16) // just change its (shallow) copy
  xmap: function (thisobj, func, changeself, extraargs) { // map this with thisobj.fuc
    var i = 0, len = this.length;
    if (! (extraargs instanceof Array)) {
      extraargs = Array.prototype.slice.call(arguments, 3);
    }
    if (changeself) {
      for (i=0; i < len; ++i) {
        this[i] = func.apply(thisobj, [ this[i] ].concat(extraargs));
      }
    } else {
      for (i=0; i < len; ++i) {
        func.apply(thisobj, [ this[i] ].concat(extraargs));
      }
    }
    return this;
  }
});