Analyzing and modifying data types

We have seen the primitive data types. There are some built-in JavaScript methods that will help us deal with common problems related to primitives. Built-in methods are pieces of logic that can be used without having to write JavaScript logic yourself.

We've seen one built-in method already: console.log().

There are many of these built-in methods, and the ones you will be meeting in this chapter are just the first few you will encounter.

Working out the type of a variable

Especially with null and undefined, it can be hard to determine what kind of data type you are dealing with. Let's have a look at typeof. This returns the type of the variable. You can check the type of a variable by entering typeof, then either a space followed by the variable in question, or the variable in question in brackets:

testVariable = 1;
variableTypeTest1 = typeof testVariable;
variableTypeTest2 = typeof(testVariable);
console...