Created
March 5, 2012 18:44
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construct -- an alternate way to invoke constructor functions
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// Bind another function as the `this` context for `construct` to create | |
// a method that will construct the given function and return the object | |
// directly, enabling immediate chaining. | |
// | |
// A bound version of `construct` can be thought of as a Functor, converting data in (the function) | |
// to a new kind of data out (the constructed object). | |
// | |
// Before: | |
// | |
// var f = new F(); | |
// f.foo(); | |
// | |
// After: | |
// | |
// var F = construct.bind(F); | |
// F().foo(); | |
// | |
// Or use it to enforce `new` on constructors that support flexible arguments: | |
// | |
// var F = function () { | |
// if (!(this instanceof F)) return construct.apply(F, arguments); | |
// } | |
// | |
// You can also assign it to any function as an alternative function-based | |
// construction method that is compatible with `apply`: | |
// | |
// F.construct = construct; | |
// var f = F.construct(1, 2, 3); | |
var construct = function () { | |
var F = this, | |
// Create an object that prototypally inherits from the prototype of `F`. | |
// This is akin to calling `new F(...)`, but without invoking the | |
// function code in `F`. | |
self = Object.create(F.prototype); | |
self.constructor = F; | |
// Invoke the constructor function, passing our object to it. Between | |
// creating the object and invoking the constructor, you get essentially | |
// the same lifecycle as `new F(...)`. All this jiggery-pokery is to | |
// work around the fact that calling a function as a constructor with | |
// an array of arguments is hard. | |
F.apply(self, arguments); | |
return self; | |
}; |
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A better solution than https://gist.github.com/1700841 to the problem of object construction via functions.