CODEWITHSUNDEEP
javascript
jsnewb
jsnewb

Reputation: 45

How to access a setter through an instance of object.create

On mozilla website they say: 

// Example where we create an object with a couple of sample properties.
// (Note that the second parameter maps keys to *property descriptors*.)
o = Object.create(Object.prototype, {
  // foo is a regular 'value property'
  foo: { writable: true, configurable: true, value: 'hello' },
  // bar is a getter-and-setter (accessor) property
  bar: {
    configurable: false,
    get: function() { return 10; },
    set: function(value) { console.log('Setting `o.bar` to', value); }
/* with ES5 Accessors our code can look like this
    get function() { return 10; },
    set function(value) { console.log('setting `o.bar` to', value); } */
  }
});

But when I run this code, I can call o.bar but but do I call the set method?

o.bar calls the get, but what do I do to call the set?

Here's the code set up with a fiddle LINK

Upvotes: 1

Views: 34

Answers (2)

Scott Sauyet
Scott Sauyet

Reputation: 50797

If you want to deal with the issues raised by @CyberneticTwerkGuruOrc, you can write it like this, storing the actual value in an internal closure variable:

o = Object.create(Object.prototype, {
   foo: { writable: true, configurable: true, value: 'hello' },
   bar: (function() {
     var internalValue = 10; 
     return {
       configurable: false,
       get: function() { return internalValue; },
       set: function(value) { 
         console.log('Setting `bar` to', value); 
         internalValue = value;
       }
     };
   }())
});

o.bar; //=> 10
o.bar = 12; // logs 'Setting `bar` to 12'.
o.bar; //> 12

Upvotes: 1

Ragnar
Ragnar

Reputation: 543

Simply set the o.bar like this to call the 'set' function:

o.bar = 3
Setting `o.bar` to 3
3

EDIT:

As @CyberneticTwerkGuruOrc mentions in the comments, the setter does not set anything in this case. To do so you have to use the input value and actually set some (other) value, ex: this.foo = value

Upvotes: 3

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