Javascript typeof Operator

Introduction

When defining Javascript variables we do not need to define type.

To determine the data type of a given variable, use the typeof operator.

Javascript typeof tells you the type information for a variable.

Using the typeof operator on a value returns one of the following strings:

Returned String Meaning
"undefined"if the value is undefined
"boolean" if the value is a Boolean
"string" if the value is a string
"number" if the value is a number
"object"if the value is an object or null
"function" if the value is a function
"symbol" if the value is a Symbol

The typeof operator is called like this: 

let message = "some string"; 
console.log(typeof message);   // "string" 
console.log(typeof(message));  // "string" 
console.log(typeof 95);        // "number"

typeof is an operator and not a function, no parentheses are required.

Calling "typeof null" returns a value of "object", as null is an empty object reference.




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