In JavaScript, there are various built-in types such as numbers, strings, booleans, and objects. You might often encounter situations where you need to determine the type of a value. Fortunately, JavaScript provides us with the typeof
operator to accomplish this task.
To use the typeof
operator, simply write the keyword typeof
followed by the value or variable you want to check. Let’s take a closer look at how this works:
typeof 'test'
Executing the above code will return a string representing the type of value. Here are the possible values it can return:
'number'
'string'
'boolean'
'undefined'
'bigint'
'symbol'
'object'
'function'
It’s important to note that JavaScript does not have a distinct null
type. If you use typeof
on null
, it will incorrectly return 'object'
.
typeof null
The code above will result in 'object'
.
Similarly, arrays in JavaScript are considered objects, so using typeof
on an array will also return 'object'
.
typeof [1, 2, 3] //'object'
Functions, on the other hand, are a special type of object in JavaScript. While you can add properties and methods to functions, their type will be 'function'
when you use the typeof
operator.
const talk = () => {}
talk.test = true
In summary, the typeof
operator in JavaScript allows you to determine the type of a value. Keep in mind that it’s not a function but an operator, so you don’t need to use parentheses. By using typeof
, you can easily handle different types of values in your JavaScript code.