basicOfES10.js

// #1 Turning this array into a new array: [1,2,3,[4],[5]].
const array = [[1], [2], [3], [[[4]]], [[[5]]]];

console.log(array.flat(2)); // [ 1, 2, 3, [ 4 ], [ 5 ] ]

// #2 Turning this array into a new array: [ 'Hello young grasshopper!', 'you are', 'learning fast!' ]
const greeting = [
  ["Hello", "young", "grasshopper!"],
  ["you", "are"],
  ["learning", "fast!"],
];

console.log(greeting.flatMap((x) => x.join(" "))); // [ 'Hello young grasshopper!', 'you are', 'learning fast!' ]

//#3 Turning the greeting array above into a string: 'Hello young grasshopper you are learning fast!'

console.log(greeting.flatMap((x) => x.join(" ")).join(" ")); // Hello young grasshopper! you are learning fast!

//#4 Turning the trapped 3 number into: [3]
const trapped = [[[[[[[[[[[[[[[[[[[[[[[[[[3]]]]]]]]]]]]]]]]]]]]]]]]]];

console.log(trapped.flat(Infinity)); // [ 3 ]
// Infintiy is actually a LARGE number in JavaScipt. It represents the maximum amount of memory that we can hold for a number! For more here: https://riptutorial.com/javascript/example/2337/infinity-and--infinity

//#5 Cleaning up this email to have no whitespaces. Make the answer be in a single line (return a new string):
const userEmail3 = "     cannotfillemailformcorrectly@gmail.com   ";

console.log(userEmail3.trimEnd().trimStart()); // cannotfillemailformcorrectly@gmail.com

//#6 Turning the below users (value is their ID number) into an array: [ [ 'user1', 18273 ], [ 'user2', 92833 ], [ 'user3', 90315 ] ]
const users = { user1: 18273, user2: 92833, user3: 90315 };

const usersArray = Object.entries(users);

//#7 changing the output array of the above to have the user's IDs multiplied by 2 -- Should output:[ [ 'user1', 36546 ], [ 'user2', 185666 ], [ 'user3', 180630 ] ]

updatedUsersArray = usersArray.map((user) => [user[0], user[1] * 2]);

//#8 changing the output array of  #7 back into an object with all the users IDs updated to their new version. Should output: { user1: 36546, user2: 185666, user3: 180630 }

const updatedUsers = Object.fromEntries(updatedUsersArray);
console.log(updatedUsers); // { user1: 36546, user2: 185666, user3: 180630 }

// Array.flat() && Array.flatMap
const jobs = [
  ["👮🏻", "💂🏻"],
  ["👷🏻‍♂️", "🤴🏻"],
];
const flatJobs = jobs.flat(); // same as: const flatJobs = jobs.flat(1);

console.log(flatJobs); // ['👮🏻', '💂🏻', '👷🏻‍♂️', '🤴🏻']

const jobsList = [
  ["👮🏻", "💂🏻"],
  ["👷🏻‍♂️", "🤴🏻", ["🎅🏻", ["🦸🏻"], "🦹🏻‍♀️"]],
];
const flatJobsList = jobsList.flat(Infinity); // Infinity: flatten an array of arbitrary depth

console.log(flatJobsList); // ['👮🏻', '💂🏻', '👷🏻‍♂️', '🤴🏻', '🎅🏻', '🦸🏻', '🦹🏻‍♀️']

const names = ["police", "guard", "builder", "princess"];

const mappedOnly = flatJobs.map((job, index) => [job, names[index]]);
const mappedAndFlatten = flatJobs.flatMap((job, index) => [job, names[index]]);

console.log(mappedOnly); // [['👮🏻', 'police'], ['💂🏻', 'guard'], ['👷🏻‍♂️', 'builder'], ['🤴🏻', 'princess']]
console.log(mappedAndFlatten); //  ['👮🏻', 'police', '💂🏻', 'guard', '👷🏻‍♂️', 'builder', '🤴🏻', 'princess']

// From Entries
const fruits = { lemon: "🍋", pineapple: "🍍", mango: "🥭", apple: "🍏" };
const entries = Object.entries(fruits);

console.log(Object.entries(fruits)); // [['lemon', '🍋'],['pineapple', '🍍'],['mango', '🥭'],['apple', '🍏']]
console.log(Object.fromEntries(entries)); // {lemon: '🍋', pineapple: '🍍', mango: '🥭', apple: '🍏'}

// String.trimStart() & String.trimEnd()
const fruitsList = "    🥭🍏🍍     ";
console.log(fruitsList.trimEnd()); // "    🥭🍏🍍";
console.log(fruitsList.trimStart()); // "🥭🍏🍍     ";

// Stable Array.prototype.sort()
const fruitsArr = [
  { name: "🥝", units: 12 },
  { name: "🫐", units: 14 },
  { name: "🍏", units: 16 },
  { name: "🥬", units: 15 },
  { name: "🍊", units: 18 },
  { name: "🍐", units: 19 },
];

// Create our own sort criteria function:
const sortCriteria = (fruit1, fruit2) => fruit1.units - fruit2.units;

// Perform stable ES10 sort:
const sorted = fruitsArr.sort(sortCriteria);

console.log(sorted);
// [
//   { name: "🥝", units: 12 },
//   { name: "🫐", units: 14 },
//   { name: "🥬", units: 15 },
//   { name: "🍏", units: 16 },
//   { name: "🍊", units: 18 },
//   { name: "🍐", units: 19 },
// ];