how to find the type of variable in js code example

Example 1: javascript how to know type of variable

var foo = "Hello";
console.log(typeof foo); // string

Example 2: get type of var js

var x = 12345; 
console.log(typeof x) // number
x = 'string'; 
console.log(typeof x) // string
x = { key: 'value' };
console.log(typeof x) // object