An alternative to JavaScript's new operator added in ECMAScript 5 and championed by Douglas Crockford.
Object.create() is an alternative to JavaScript's new operator added in ECMAScript 5 and championed by Douglas Crockford.
Questions tagged [object-create]
71 questions
436
votes
11 answers
Understanding the difference between Object.create() and new SomeFunction()
I recently stumbled upon the Object.create() method in JavaScript, and am trying to deduce how it is different from creating a new instance of an object with new SomeFunction(), and when you would want to use one over the other.
Consider the…
Matt
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votes
15 answers
Using "Object.create" instead of "new"
Javascript 1.9.3 / ECMAScript 5 introduces Object.create, which Douglas Crockford amongst others has been advocating for a long time. How do I replace new in the code below with Object.create?
var UserA = function(nameParam) {
this.id =…
Graham King
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125
votes
5 answers
JavaScript inheritance: Object.create vs new
In JavaScript what is the difference between these two examples:
Prerequisite:
function SomeBaseClass(){
}
SomeBaseClass.prototype = {
doThis : function(){
},
doThat : function(){
}
}
Inheritance example A using…
ChrisRich
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votes
5 answers
What is difference between creating object using Object.create() and Object.assign()?
Considering following code:
var obj1 = Object.create({}, {myProp: {value: 1}});
var obj2 = Object.assign({}, {myProp: 1});
Is there any difference between obj1 and obj2 since each object has been created in a different way?
madox2
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25
votes
2 answers
Instanceof equivalent for Object.create and prototype chains
Consider such an object with a prototype chain:
var A = {};
var B = Object.create(A);
var C = Object.create(B);
How to check in runtime if C has A in its prototype chain?
instanceof doesn't fit as it's designed to work with constructor functions,…
Kos
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19
votes
1 answer
How does object.create work in JavaScript?
Tell me if I'm wrong:
A prototype is a normal object. When an object inherits a prototype, it does not just copy the properties of the prototype, the object stores a reference to the prototype.
In Firefox, I can do:
var food = {fruit:"apple"};
var…
Brian
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17
votes
4 answers
Why is Object.create so much slower than a constructor?
Background
In a project I'm maintaining we make extensive use of null prototype objects as a poor man's alternative to (string key only) Maps, which are not natively supported in many older, pre-ES6 browsers.
Basically, to create a null prototype…
GOTO 0
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15
votes
7 answers
JavaScript inheritance with Object.create()?
How do I inherit with the Object.create()? I tried these, but none are working:
var B = function() {};
var A = function() {};
A = Object.create(B);
A.prototype.C = function() {};
and
var B = function() {};
var A = function() {};
A.prototype.C =…
Tower
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13
votes
3 answers
JavaScript Object.create -- inheriting nested properties
I've come across a peculiarity with Douglas Crockfords Object.create method which I'm hoping someone might be able to explain:
If I create an object - say 'person' - using object literal notation then use Object.create to create a new object - say…
Richard
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11
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4 answers
Is there any reason to use Object.create() or new in JavaScript?
I've been using the new keyword in JavaScript so far. I have been reading about Object.create and I wonder if I should use it instead. What I don't quite get is that I often need to run construction code, so I don't see how Object.create is going to…
Tower
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10
votes
2 answers
Javascript Arrays created with Object.create - not real Arrays?
It looks like Arrays created with Object.create walk like Arrays and quack like Arrays, but are still not real arrays. At least with v8 / node.js.
> a = []
[]
> b = Object.create(Array.prototype)
{}
> a.constructor
[Function: Array]
>…
Philippe Plantier
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10
votes
1 answer
Advantage of using Object.create
Similar to, but different from this question. The code below is from JavaScript: The Definitive Guide. He's basically defining an inherit method that defers to Object.create if it exists, otherwise doing plain old Javascript inheritance using…
Adam Rackis
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5 answers
Understanding Crockford's Object.create shim
I've been reading up on the Crockford shim for preventing the overwriting of prototypes, and understand that it's not the end-all/be-all solution at times. I also understand that ES5 Shim may be a viable alternative to this. I also read this post…
kaidez
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9
votes
2 answers
Object.create vs direct prototypical inheritance
I have been playing around with Object.create in the EcmaScript 5 spec, and I am trying to create a multiple inheritance type structure.
Say I have a few functions: a, b, and c. With only dealing with prototypes, I can do this:
function a ()…
beatgammit
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8
votes
4 answers
Prototypal OO with Object.create and named constructors
I'm coming to Javascript from a background in Python and Smalltalk, and I appreciate the linage of Self and Lisp in the language. With ECMAScript5, I wanted to try my hand at prototypal OO without the new operator.
Constraints:
optional new…
Shane Holloway
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