js define data type by text code example
Example 1: data types in javascript
1, 1.0 // Number
'String', "String"
true, false // Boolean
{id: 1;} // Object
[1, 2, 3] // Array
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,, "