TypeOf Operator

    // typeof.js
    // The typeof operator
    //
    let log = console.log;
    let str = "Winchester";			// typeof returns string
    let num = 13;					// typeof returns number
    let bool = true;				// typeof returns boolean
    
    let obj = {'prop':'Dean'};				    // typeof returns object
    let arr = ['Sam', 'Castiel', 'Crowley'];	// typeof returns object
    
    let today = new Date( );		// typeof returns object
    let dt = Date( );				// typeof returns string
    let f = function( ){			// typeof returns function
           // Hi. I’m a function
    }
    
    log(typeof NaN);				// typeof returns number
    log(typeof undefined);			// typeof returns undefined
    log(typeof null);				// typeof returns object