1var age = 18;                           // number 
2var name = "Jane";                      // string
3var name = {first:"Jane", last:"Doe"};  // object
4var truth = false;                      // boolean
5var sheets = ["HTML","CSS","JS"];       // array
6var a; typeof a;                        // undefined
7var a = null;                           // value null
8

1
2let x = "16" + "Volvo"; 

1dataTypes = {
2    Numbers = 1,2,3, 100, 3.14
3    Strings = 'Hello, World' "helloworld@gmail.com
4    Boolean = true / false
5    Null = 'Explicitly set a variable with no Value'
6    Undefined = 'For variable that have not yet been defined'
7    Object = 'Complex data structures - Arrays, Dates, Literals etc'
8    Symbol = 'Used with objects' // usually not needed
9}

1
2let length = 16;                               // Number
3
4let lastName = "Johnson";                      // String
5
6let x = {firstName:"John", lastName:"Doe"};    // Object
7 

1let length = 16;                               // Number
2let lastName = "Johnson";                      // String
3let x = {firstName:"John", lastName:"Doe"};    // Object