Object Categories

JavaScript uses a mix of terminology to describe objects found in the standard as opposed to those added by execution environments such as the browser or Node.js, and the ECMAScript 6 specification has clear definitions for each category of object. It’s important to understand this terminology to have a good understanding of the language as a whole. The object categories are:

• Ordinary objects Have all the default internal behaviors for objects in JavaScript.
• Exotic objects Have internal behavior that differs from the default in some way.
• Standard objects Are those defined by ECMAScript 6, such as Array, Date, and so on. Standard objects may be ordinary or exotic.
• Built-in objects Are present in a JavaScript execution environment when a script begins to execute. All standard objects are built-in objects.

I will use these terms throughout the book to explain the various objects defined by ECMAScript 6.