es2020_samples.js

/**
 * ! Babel plugins
 * * @babel/plugin-proposal-nullish-coalescing-operator
 * * @babel/plugin-proposal-optional-chaining
 * * @babel/plugin-proposal-class-properties
 * * @babel/plugin-proposal-private-methods
 * * @babel/plugin-syntax-bigin
 */

// ! Private class variables
class Message {
    #message = "howdy";

    greet() {
        console.log(this.#message);
    }
}

const greeting = new Message();

greeting.greet();
console.log(greeting.#message); // Private name #message is not defined

// ! Promise.allSettled

const p1 = new Promise((res, rej) => setTimeout(res, 1000));

const p2 = new Promise((res, rej) => setTimeout(rej, 1000));

Promise.allSettled([p1, p2]).then(data => console.log(data));

// [
//   Object { status: "fulfilled", value: undefined},
//   Object { status: "rejected", reason: undefined}
// ]

// ! Nullish Coalescing Operator

let person = {
    profile: {
        name: "",
        age: 0
    }
};

// coalescing
console.log(person.profile.name ?? "Anonymous"); // ""
console.log(person.profile.age ?? 18); // 0

// Or expression
console.log(person.profile.name || "Anonymous"); // Anonymous
console.log(person.profile.[age] || 18); // 18

// ! Optional Chaining Operator

let person = {};

// console.log(person.profile.name ?? "Anonymous"); // person.profile is undefined
console.log(person?.profile?.name ?? "Anonymous"); // Anonymous
console.log(person?.profile?.age ?? 18); // 18

// ! BigInt

// Normal integers
const max = Number.MAX_SAFE_INTEGER;

console.log(max); // 9007199254740991

console.log(max + 1); // 9007199254740992
console.log(max + 2); // 9007199254740992
console.log(max + 3); // 9007199254740994
console.log(Math.pow(2, 53) == Math.pow(2, 53) + 1); // true

const bigNum = 100000000000000000000000000000n;

console.log(bigNum * 2n); // 200000000000000000000000000000n

// ! Dynamic Import
// Why dynamic imports?
// * they are not limited to the top level of the file
// * they can be loaded conditionally (inside an if)
// * the name of the package can be determined at execution time

const doMath = async (num1, num2) => {
    if (num1 && num2) {
        const math = (await import('./math.js')).default;
        console.log(math);
        console.log(math.add(5, 10));
    } else {
        console.log('2 nums req');
    }
};

doMath(4, 0);