Day14 of #100DaysOfCode

#CodeTogether Day 14/100

Hii folks 🙌

Today I have completed the 14th video of JavaScript30!

Project 14: Object and Arrays — Reference VS Copy

Source: https://javascript30.com

Learnings:

• strings, numbers, and booleans

Javascript will make copies of these types, so changing the values like below is okay.

let age = 100;
let age2 = age;

age = 200;

In this case, the age2 variable will keep its originally assigned value of 100 .

• array

When dealing with arrays, you need to be aware of the concept of references.

const players = ['Kushagra', 'Sarah', 'Ryan', 'Poppy'];
const team = players;

Here, modifying the team array's values will actually modify the players array, for example…

team[3] = 'Lux';

console.log(players[3]); // 'Lux'

To leave the original array intact, you must make copies of it. There are multiple ways of doing this, some are shown below.

const team2 = players.slice();
const team3 = [].concat(players);
const team4 = [...players];
const team5 = Array.from(players);

• objects

The same principle of referencing (from arrays) applies here. To copy an object to another variable, the following code would work

const person = {
    name: 'Kushagra Kesav',
    age: 20
};

const cap2 = Object.assign({}, person, { age: 99 });

The Object.assign() method takes in the following parameters:

• target - In this case, a blank object {}
• sources - Object(s) to add

The additional argument.

• {age: 99} - This will modify the existing age variable in person

Things to note — this is only 1 level deep — both for Arrays and Objects, which means it will update the embedded object that is `social.twitter` and `social. medium`, even if you update the copy of the object!!

const details = {
      name: 'Kushagra',
      age: 100,
      social: {
        twitter: '@im_Kushagra',
        medium: '@imKushagra'
      }
    };
console.log(details);
const dev = Object.assign({}, details);

To, skip that functionality or cheat the way out you can use the following line of code to create the copy of the object! (not recommended)

const dev2 = JSON.parse(JSON.stringify(details));

Today I learned (T-I-L):

• Objects & Arrays in JS
• String, Number & Booleans in JS
• Difference between JS referencing and copying
• The embedded object will get updated even after copying the object ✨

That is all for Day14 ✅

Thanks for reading, See you tomorrow!