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Oneself turns methods into functions with an explicit self.

So instead of writing:, 1);

you can create a reusable function that takes this as the first parameter.

var slice = oneself(Array.prototype.slice);
slice(arguments, 1)

As a convenenience, oneself provides all Array methods as functions under oneself.array, along with functions in string, date, regexp and object.

var slice = oneself.array.slice;
slice(arguments, 1)
var map =,
    getFullYear =;
  map([new Date(2011, 3, 15), new Date(2012, 5, 25)], getFullYear),
  [2011, 2012]);

If desired, you can extend the object itself:

listEqual(['eB', 'CF'], String.toLowerCase),
  ['eb', 'cf']);

As shown above, these functions are useful to map this over collections of objects. oneself also provides placeholder functions that allow you to map methods with specified arguments, named the same as the methods, with a _ suffix.

  map([/(.)/, /g$/, /o/, /o$/], oneself.regexp.test_('dog')),
  [true, true, true, false]);


You can create functions from any object as an alternative to binding this.

  function Point(x, y){
    this.x = x;
    this.y = y;
  function point(x, y){
    return new Point(x, y);
  Point.prototype.toString = function(){
    return '('+this.x+''+this.y+')';
  Point.prototype.describe = function(){
    return 'Point '+this.toString();
  Point.prototype.add = function(x, y){
    return new Point(this.x + x, this.y+y);
  var p1 = point(1,2);
  var describePoint = oneself(Point.prototype.describe);
  equal(describePoint(p1), p1.describe());

As well as placeholder functions:

var add1_1 = oneself(Point.prototype.add)._(1,1);
equals(add1_1(p1), point(2, 3));

Although it might be better to shim your objects. This will create functions for all enumerable methods along with toString.

  map(map([point(1,2), point(3,4)], Point.add_(10, 20)), Point.toString),
  ['(11, 22)', '(13, 24)']);


oneself makes use of uncurryThis, described here, which is also available under oneself.uncurryThis

The companion, curryThis, can be used to avoid that = this:

  var x = {
    b: 'hi',
    c: function(w){
      return this.b+' '+w+'!';
    a: oneself.curryThis(function(self, cb){
      }, 100);