Learning JavaScript, 2nd Edition

Chapter 4. The JavaScript Objects

The JavaScript objects are inherent components of the JavaScript language itself, and not the environment in which the JavaScript is processed. As such, they’ll always be available regardless of environment.

Among the basic JavaScript objects are those that parallel our data types, which we discussed in Chapter 2: String for strings, Boolean for booleans, and of course, Number for numbers. They encapsulate the primitive types, providing additional functionality beyond the basic conversion functionality we discussed in that chapter.

Three additional built-in objects provide necessary functionality as well: Math, Date, and RegExp. Math and Date are relatively self-explanatory; they provide basic math and date functionality. If you haven’t worked with regular expressions before, RegExp is the object that provides regular expression functionality. Regular expressions are powerful though extremely cryptic patterning capabilities that enable you to add very precise string matching to applications.

JavaScript also has one built-in aggregator object, the Array. All objects in JavaScript, in fact, are arrays, though we don’t typically treat the objects as arrays. I’ll discuss this in more detail later in the chapter. First, though, we’ll revisit the basic data type objects introduced earlier, as we explore exactly what it means to be an “object” in JavaScript.

Primitive Data Types As Objects

I’ll get into the details of JavaScript’s object-oriented nature later ...