armd_array.js

/*
.__..__ .  ..__ 
[__][__)|\/||  \
|  ||  \|  ||__/
ARMD its Add, Read, Modify, Delete
*/

const users = [
  {
    id: 1,
    name: "Jonathon Haley",
    username: "Monte.Weber2",
    email: "[email protected]",
  },
  {
    id: 2,
    name: "Dean John",
    username: "dd.1",
    email: "[email protected]",
  }
];


// 1. ADD — Adding a new element to users
const newUser = {
    id: 4,
    name: "Denomer Crazy",
    username: "crazy.1",
    email: "[email protected]",
};
const newData = [...users, newUser]; // add element at last
const newData = [newUser, ...users]; // add element at first
const newData = users.concat(newUser) // the old way

// Extra! this will add hobbies to users array and return newUsers array
const hobbies = ['chess', 'pool'];
const newUsers = users.map(u => ({...u, hobbies}));


// 2. READ — Get email address, phone number and website of users into new array
const contactInfo = users.map(({email, website, phone}) => ({email, website, phone}));


// 3. MODIFY — Find and replace value for key of objects
const newUsers = users.map(u => u.id == 2? ({...u, name: 'te'}): u);
// this will return newUsers with all user having name 'te'


// 4. DELETE — Delete some key’s from object
const newUsers = users.map({id, email, name, username, phone, password} => ({id, email, username, email, phone, password}));
// will return an array with all keys other than website

// Above code seems to be practically difficult to code for big objects.
const newUsers = users.map(u => Object.keys(u).reduce((newObj, key) => key != 'website' ? { ...newObj, [key]: u[key]} : newObj, {}));