January 2017
Beginner to intermediate
550 pages
10h 6m
English
Content preview from Object-Oriented JavaScript - Third EditionBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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Object properties and attributes
Each object has a few properties. Each property, in turn, has a key and attributes. A property's state is stored in these attributes. All properties have the following attributes:
- Enumerable (boolean): This indicates if you can enumerate the properties of the object. System properties are non-enumerable while user properties are enumerable. Unless there is a strong reason, this property should remain untouched.
- Configurable(boolean): If this attribute is
false, the property cannot be deleted or edited (it cannot change any of its attribute).
You can use the Object.getOwnPropertyDescriptor() method to retrieve an object's own properties:
let obj = { age: 25 } console.log(Object.getOwnPropertyDescriptor(obj, 'age')); ...Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.