JavaScript_Succinctly

Sample: sample79.html
var yelp = function () {
console.log('I am yelping!');
// Functions return undefined even if we don't.
}
/* Logs true because a value is always returned, even if we don't
specifically return one. */
console.log(yelp() === undefined);
The concept to take away here is that all functions return a value, even if you do not
explicitly provide a value to return. If you do not specify a value to return, the value
returned is undefined.
Functions are first-class citizens (not just syntax, but values)
In JavaScript, functions are objects. This means that a function can be stored in a
variable, array, or object. Also, a function can be passed to and returned from a
function. A function has properties because it is an object. All of these factors make
functions first-class citizens in JavaScript.
Sample: sample80.html
// Functions can be stored in variables (funcA), arrays (funcB), and
objects (funcC).
var funcA = function () { }; // Called like so: funcA()
var funcB = [function () { } ]; // Called like so: funcB[0]()
var funcC = { method: function () { } }; // too.method() or
funcC['method']()
// Functions can be sent to and sent back from functions.
var funcD = function (func) {
return func
};
var runFuncPassedToFuncD = funcD(function () { console.log('Hi'); });
runFuncPassedToFuncD();
// Functions are objects, which means they can have properties.
var funcE = function () { };
92