Руслан Куянец | Reactify

function Animal(name, sound) {
    this.name = name;
    this.sound = sound;
    this.makeSound = () => {
        console.log(`${this.name} says ${this.sound}`);
    };
}

const dog = new Animal('Dog', 'Woof');
dog.makeSound(); // 'Dog says Woof'

const obj = {
    name: 'Dog',
    sound: 'Woof',
    makeSound: () => {
        console.log(`${this.name} says ${this.sound}`);
    }
};

obj.makeSound(); // undefined says undefined

Вы не можете контролировать ветер, но вы можете настроить паруса.

function Animal(name, sound) {
    this.name = name;
    this.sound = sound;
    this.makeSound = () => {
        console.log(`${this.name} says ${this.sound}`);
    };
}

const dog = new Animal('Dog', 'Woof');
dog.makeSound();

const getMedian = (arr1, arr2) => {};

// Пример вызова функции:
getMedian([1, 3, 15, 20], [2, 3, 4, 13, 16]); // Ожидаемый результат: 4

function fn1(a) {
    a = a + 1
}

let a = 1
fn1(a)
console.log(a) // output: ?

function fn2(b) {
    b = b + 1
    return b
}

let b = 1
fn2(b)
console.log(b) // output: ?

function fn3(obj) {
    obj.c = obj.c + 1
}

let obj = { c: 1 }
fn3(obj)
console.log(obj.c) // output: ?

function fn4(arr) {
    arr[1] = arr[1] + 1
}

let arr = [1, 2, 3]
fn4(arr)
console.log(arr) // output: ?

let str = '123'
str.abc = 'xxx' // Что будет?
console.log(str.abc) // Что будет?

const SomeComponent = () => {
    const [count, setCount] = useState(0)

    function upCount() {
        setCount(count + 1)
    }

    const sendToAnalytic = useCallback((...args) => {
        // doesn't matter
        // some API
    }, [])

    useEffect(() => {
        sendToAnalytic(count)
    }, [count, sentToAnalytic])

    return <button onClick={upCount}>UP</button>
}

interface SomeObject {
    a: number
    b: string
    c: boolean
    d: string
}

type onlyStringKeys = ? // output: 'b' | 'd'