objects

creating an object

Using Object litteral

this is the simplest way of creating a javascript object
you simply create a variable an assign it to an object with specified properties

const person = { name: "salah", age: 22 }; 

using constructors

constructor are methods that creates an instate object based on given values passed as parameters,
the properties of that object are spercifed in the method implementation .
here we define our constructor:

function Person(name_, age_) { this.name = name_; this.age = age_; this.Greeting = function () { console.log("hi, My name is " + this.name); } } 

and now we only initialize a new instance of Person
let salah = new Person("salah", 25);
so here we can access our objects promerties and methods

salah.Greeting(); console.log(salah.age); console.log(salah.name); 

using factory functions

var personFF = function(name_, age_) { return { name_, age_ //we can add methods and properties here }; }; var khalid = personFF("khalid", 15); console.log(khalid); 

using the Object.clone() method

to clone an object is another choice we have.
this method takes one or more objets as parameters and then creates a new object based o what's given

var hamza = Object.assign(khalid); hamza.name_ = "hamza"; 

as we can see the assign method copies the values of an object by reference.
so when we changed the second object's property name the first object's property changed to and vise-versa.

console.log(hamza); console.log(khalid); 

same thing if we try to change the age property

khalid.age_ = 33; console.log(hamza); console.log(khalid); 

so now both objects are referncing the same memory adress
to prevent this problem we can use the spread operator
using the spread operator

var ayoube = { ...khalid // this ... is called the spread operator it basically spreads an object's properties into another object }; console.log(ayoube); ayoube.name_ = "ayoube"; 

so now even if we change the second object the first object stays the same and vise versa.

console.log(ayoube); console.log(khalid); 

using the create method
a better way to prevent this problem is the create method
it creates an empty object based on an exesting object's properties.

var khalil = Object.create(khalid); console.log(khalil); console.log(khalid); 

so now we have an object called khalil that has the same properties as khalid (name* and age*)
but the with no values yet.

khalil.name_ = "khalil"; khalil.age_ = 25; console.log(khalil); console.log(khalid);