define property array of objects in Javascript

Question

I have initialized an object that I wish to add to dynamically. Specifically I want to add array of objects to this object. I have tried the below but neither work.. is there a way to do this correctly? The final output should be object1.property1[0].value = 42 and object1.property1[0].writable = false.

const object1 = {};

Object.defineProperty(object1, 'property1', '' );
object1.property1 = [{value: 42, writable: false}];


const object1 = {};
Object.defineProperty(object1, 'property1', [{value: 42, writable: false}] );

Object.defineProperty(object1, 'property1', { value: [{value: 42, writable: false}] }); — guijob, Mar 06 '18 at 02:33

score 2 · Answer 1 · edited Mar 06 '18 at 02:42

2

Try using value property from descriptor argument:

const object1 = {};
Object.defineProperty(object1, 'property1', {
  value: [{
    value: 42,
    writable: false
  }]
});

console.log(object1.property1[0].value);
console.log(object1.property1[0].writable);

edited Mar 06 '18 at 02:42

vol7ron

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answered Mar 06 '18 at 02:36

guijob

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score 0 · Answer 2 · answered Mar 06 '18 at 02:34

0

The object descriptor must be declared as follow:

{value: [{value: 42}], writable: false}

const object1 = {};

Object.defineProperty(object1, 'property1', {value: [{value: 42}], writable: false});

console.log(object1.property1[0].value)

answered Mar 06 '18 at 02:34

Ele

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vol7ron · Answer 3 · 2018-03-15T04:28:05.577

Since you specified you wanted to add an array of objects to the object, this solution is similar to other answers, but should demonstrate adding an array with more than one element:

const obj = {};
Object.defineProperty(obj, 'property', {
  value: [{
      value: 42,
      writable: false
    },
    {
      value: 55,
      writable: false
    }
  ]
});

console.log(obj.property[0].value);
console.log(obj.property[0].writable);

console.log(obj.property[1].value);
console.log(obj.property[1].writable);

Of course, your writable isn't going to do anything, since it'll be treated as just another property. Due to the fact that your property is an array of objects (e.g., [{...},{...}]), what you may want to do is iterate over that array and freeze those objects:

obj.property.forEach(o=>Object.freeze(o))
obj.property[0].value=33;  // when frozen you won't be able to update the value

define property array of objects in Javascript

3 Answers3