what is the default data type in javascript code example

Example 1: js data types

//There are 7 data types in JS 
//They're split in two categories - (Primitives and Complex Types)

//Primives
string, number, boolean, null, undefined

//Complex types
Object, Function

Example 2: javascript all type of data

let a = ["A", 1, true, [], [2, 'x'],{},{a:'B'}, NaN, undefined, null];
let s = a.toString();
console.log(s);//"A,1,true,,2,x,[object Object],[object Object],NaN,, "