soft (weak) bind in JS

soft-bind.js

if (!Function.prototype.softBind) {
  Function.prototype.softBind = function(obj) {
    var fn = this,
      curried = [].slice.call(arguments, 1),
      bound = function bound() {
        return fn.apply(
          !this ||
            (typeof window !== 'undefined' && this === window) ||
            (typeof global !== 'undefined' && this === global)
            ? obj
            : this,
          curried.concat.apply(curried, arguments),
        );
      };
    bound.prototype = Object.create(fn.prototype);
    return bound;
  };
}

function foo() {
  console.log("name: " + this.name);
}

var obj = { name: "obj" },
    obj2 = { name: "obj2" },
    obj3 = { name: "obj3" };

var fooOBJ = foo.softBind( obj );

fooOBJ(); // name: obj

obj2.foo = foo.softBind(obj);
obj2.foo(); // name: obj2   <----

fooOBJ.call( obj3 ); // name: obj3   <----

setTimeout( obj2.foo, 10 ); // name: obj   <---- weak bind