024-Destruct_array_and_object.js

/* 
 * Author : Jaydatt Patel
Destructur the array or object property and copy them in other variable or object without affecting original data.
*/
console.log("--------------Destructure Array-------");

console.log("-----------1-----------");
const meal = ["soup", "steak", "ice cream"];
let [starter] = meal;
console.log(starter);

console.log("-----------2-----------");
const fruits = ["Apple", "Mango", "Kiwi", "Berry", "banana", "lichi"];
// skip elements by adding comma
var [a, , , k] = fruits;
console.log("[a, , , k]");
console.log("a :", a, ", k :", k);

var [a, m, ...arr] = fruits;
console.log("\n[a, m, ...arr]");
console.log("a :", a, ", m: ", m, ", arr :", arr);

var [a, m, ...[, be, ba]] = fruits;
console.log("\n[a, m, [ , be, ba]]");
console.log("a :", a, ", m: ", m, ", be :", be, ", ba : ", ba);

console.log("-----------3-----------");

let nestedArray = ["orange", ["apple", "banana", ["grape", "mango"]], "peach"];
let [first, [, , [third]]] = nestedArray;
console.log("\n[first, [ , ,[third]]]");
console.log("first :", first, ", third: ", third);

console.log("--------------Destructure Object-------");

var student = {}; //create an object
student.id = 123;
student.name = "Rahul";
student.degree = "BCA";
student.subjects = ["C", "C++", "JAVA", "Python"];
student.printdata = function () //add function in objects
{
  console.log(student);
};
student.getdata = function () //add function in objects
{
  console.log(this.id, this.name, this.degree, this.subjects);
};

//get copy value of id property of student
console.log("-----------4-----------");
console.log(id === student.id); // check the same property
var { id } = student; //copy value of id from student obj if not found then undefined
console.log(id);
console.log(id === student.id);

//get values of multiple properties of object in local variable
console.log("-----------5-----------");

var { id, name, subjects, xyz } = student; //copy from student obj if not found then undefined
console.log("id :", id);
console.log("name :", name);
console.log("subjects :", subjects);
console.log("xyz :", xyz);

//get values of multiple properties of object in local variable
console.log("-----------6-----------");
var { id: roll, name: nm, subjects: sub } = student; //copy from student obj if not found then undefined
console.log("roll :", roll);
console.log("nm :", nm);
console.log("sub :", sub);
console.log(roll === student.id); // check the same property

//get copy of multiple property of object in new variable name
console.log("-----------7-----------");
var num, fullname, dg;
({ id: num, name: fullname, degree: dg } = student); //copy from student obj if not found then undefined
console.log("num :", num);
console.log("fullname :", fullname);
console.log("dg :", dg);

//try to copy unkonwn property
console.log("-----------8-----------");
console.log(pop === student.id); // check the same property
var { pop } = student; //copy pop from student obj if not found then undefined
console.log(pop);
console.log(pop === student.id);