Lodash - What is the value of using _.create()

Question

In the Lodash library, what is the value of using _.create() to handle classes and instances vs other more traditional methods?

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@DanielA.White: but not exactly, as the second argument doesn't consist of property descriptors. — Bergi, Mar 10 '15 at 16:14
possible duplicate of [Using “Object.create” instead of “new”](http://stackoverflow.com/q/2709612/1048572) (and similar questions). Please [edit] your question to elaborate on what you mean by "more traditional methods", or we'll need to close it. — Bergi, Mar 10 '15 at 16:15
When you say "what is the value of using _.create()" do you mean as apposed to not using low dash at all and creating objects differently, or do you mean as opposed to still using lowdash but creating objects without _.create? — atmd, Mar 10 '15 at 16:27
I mean what is the value of using `_.create()` to handle inheritance vs any other way of handling inheritance (like the standard `Class.prototype.method_name = function()...` — JDillon522, Mar 10 '15 at 16:35
@JDillon522: That does different things. Depends on what you need. — Bergi, Mar 10 '15 at 20:19
yeah i figured. I'd like to know what the differences are so I know when to use what. — JDillon522, Mar 10 '15 at 20:20

score 2 · Answer 1 · answered Mar 10 '15 at 20:25

I don't think create() is meant to replace the existing JavaScript inheritance/prototype mechanisms. In my experience, it's been convenient when mapping collections of one type to another:

function Circle(x, y) {
    this.x = x;
    this.y = y;
}

function Square(x, y) {
    this.x = x;
    this.y = y;
}

Square.prototype.coords = function() {
    return [ this.x, this.y ];
}

var collection = [
    new Circle(1, 1),
    new Circle(2, 2),
    new Circle(3, 3),
    new Circle(4, 4)
];

_(collection)
    .map(_.ary(_.partial(_.create, Square.prototype), 1))
    .invoke('coords')
    .value();
// →
// [
//   [ 1, 1 ],
//   [ 2, 2 ],
//   [ 3, 3 ],
//   [ 4, 4 ]
// ]

score 1 · Answer 2 · answered Mar 30 '16 at 06:27

I think of it as a convenience. It's a little more succinct when doing the common task of implementing a classical inheritance model in JS.

Natively:

var User = function() {};

User.prototype = Object.create(Person.prototype);

Object.assign(User.prototype, {
  constructor: User,

  ...other stuff
});

versus _.create:

var User = function() {};

User.prototype = _.create(Person.prototype, {
  constructor: User,

  ...other stuff
});

It's just a little less to write.

score 0 · Answer 3 · answered Dec 17 '17 at 14:31

The biggest difference i see after reading some of the lodash code is that Object.create second argument, takes the format of the object.defineProperty arg, that being a property descriptor, while _.create just copies all the own or inherited enumerable properties (relies on nativeKeysIn) from the object.

It mainly eases classical object definition.

Lodash - What is the value of using _.create()

3 Answers3