Advanced JavaScript Snippets in vRO [CB10099]

var _ = System.getModule("fr.numaneo.library").lodashLibrary();
var myarr = [1,2,3];
var myarr2 = [4,5,6];
var concatarr = _.concat(myarr, myarr2);
System.log(concatarr); // [1,2,3,4,5,6];

// we send in the function as an argument to be
// executed from inside the calling function
function performOperation(a, b, cb) {
    var c = a + b;
    cb(c);
}

performOperation(2, 3, function(result) {
    // prints out 5
    System.log("The result of the operation is " + result);
})

// supported since ES3
// the dot notation
instance.key = "A key's value";

// the square brackets notation
instance["key"] = "A key's value";

// supported since ES5
// setting a single property using Object.defineProperty
Object.defineProperty(instance, "key", {
    value: "A key's value",
    writable: true,
    enumerable: true,
    configurable: true
});

// setting multiple properties using Object.defineProperties
Object.defineProperties(instance, {
    "firstKey": {
        value: "First key's value",
        writable: true
    },
    "secondKey": {
        value: "Second key's value",
        writable: false
    }
});

// we define a constructor for Person objects
function Person(name, age, isDeveloper) {
    this.name = name;
    this.age = age;
    this.isDeveloper = isDeveloper || false;
}

// we extend the function's prototype
Person.prototype.writesCode = function() {
    System.log(this.isDeveloper? "This person does write code" : "This person does not write code");
}

// creates a Person instance with properties name: Bob, age: 38, isDeveloper: true and a method writesCode
var person1 = new Person("Bob", 38, true);
// creates a Person instance with properties name: Alice, age: 32, isDeveloper: false and a method writesCode
var person2 = new Person("Alice", 32);

// prints out: This person does write code
person1.writesCode();
// prints out: this person does not write code
person2.writesCode();

// we  used an immediately invoked function expression
// to create a private variable, counter
var counterIncrementer = (function() {
    var counter = 0;

    return function() {
        return ++counter;
    };
})();

// prints out 1
System.log(counterIncrementer());
// prints out 2
System.log(counterIncrementer());
// prints out 3
System.log(counterIncrementer());

var str = '';

loop1:
for (var i = 0; i < 5; i++) {
  if (i === 1) {
    continue loop1;
  }
  str = str + i;
}

System.log(str);
// expected output: "0234"

var box = {"dimensions": {"width": 2, "height": 3, "length": 4}};
with(box.dimensions){
  var volume = width * height * length;
}
System.log(volume); //24

// vs

var box = {"dimensions": {"width": 2, "height": 3, "length": 4}};
var boxDimensions = box.dimensions;
var volume2 = boxDimensions.width * boxDimensions.height * boxDimensions.length;
System.log(volume2); //24

const module = {
  x: 42,
  getX: function() {
    return this.x;
  }
};

const unboundGetX = module.getX;
System.log(unboundGetX()); // The function gets invoked at the global scope
// expected output: undefined

const boundGetX = unboundGetX.bind(module);
System.log(boundGetX());
// expected output: 42

const o = {
  a: 1,
  b: 2,
  // __proto__ sets the [[Prototype]]. It's specified here
  // as another object literal.
  __proto__: {
    b: 3,
    c: 4,
  },
};

// o.[[Prototype]] has properties b and c.
// o.[[Prototype]].[[Prototype]] is Object.prototype (we will explain
// what that means later).
// Finally, o.[[Prototype]].[[Prototype]].[[Prototype]] is null.
// This is the end of the prototype chain, as null,
// by definition, has no [[Prototype]].
// Thus, the full prototype chain looks like:
// { a: 1, b: 2 } ---> { b: 3, c: 4 } ---> Object.prototype ---> null

System.log(o.a); // 1
// Is there an 'a' own property on o? Yes, and its value is 1.

System.log(o.b); // 2
// Is there a 'b' own property on o? Yes, and its value is 2.
// The prototype also has a 'b' property, but it's not visited.
// This is called Property Shadowing

System.log(o.c); // 4
// Is there a 'c' own property on o? No, check its prototype.
// Is there a 'c' own property on o.[[Prototype]]? Yes, its value is 4.

System.log(o.d); // undefined
// Is there a 'd' own property on o? No, check its prototype.
// Is there a 'd' own property on o.[[Prototype]]? No, check its prototype.
// o.[[Prototype]].[[Prototype]] is Object.prototype and
// there is no 'd' property by default, check its prototype.
// o.[[Prototype]].[[Prototype]].[[Prototype]] is null, stop searching,
// no property found, return undefined.