HI,
At this page
The first table:
Property attributes of Array.prototype
Writable no
Enumerable no
Configurable no
What’s mean: the true value at no?
Thanks
HI,
At this page
The first table:
Property attributes of Array.prototype
Writable no
Enumerable no
Configurable no
What’s mean: the true value at no?
Thanks
If I understand your question, you want to know what Writable, Enumerable, and Configurable mean.
configurable
true if and only if the type of this property descriptor may be changed and if the property may be deleted from the corresponding object.
Defaults to false.
enumerable
true if and only if this property shows up during enumeration of the properties on the corresponding object.
Defaults to false.
writable
true if and only if the value associated with the property may be changed with an assignment operator.
Defaults to false.
So the documentation you cited is saying that Array.prototype is not:
writable
console.log(Array.prototype) // [] Array.prototype = 'something' console.log(Array.prototype) // [] // notice we didn't change the value of Array.prototype; it isn't writable
Enumerable
// enumerating properties of Array for (var property in Array) { console.log(property) } // nothing will be printed, indicating that Array doesn't have any enumerable properties
Configurable
console.log(Array.prototype) // [] delete(Array.prototype) // false console.log(Array.prototype) // [] // we couldn't delete it; it's not configurable