How to Determine the Type of a Value in JavaScript
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:
1 | 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'.
1 | 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'.
1 | 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.
1 | const talk = () => {} |
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.
tags: [“JavaScript”, “type checking”, “typeof operator”]