Задачи с реальных собеседований на Frontend Developer

import ReactDOM from "react-dom";
import React, { memo, StrictMode, useCallback, useEffect, useLayoutEffect, useMemo, useRef, useState } from "react";

/* --------------------------------------------------------- */

const heavyFunc = (n)=>{
    return Math.floor(Math.random() * n)
}

const LazyInit = ({ num })=>{
    const [count, setCount] = useState(heavyFunc(num));

    return (
        <>
            {count}
            <button onClick={()=>setCount((prevCount) => prevCount-1)}>
                Decrement
            </button>
        </>
    )
}

/* --------------------------------------------------------- */

function App() {
    return (
        <div className="App">
            <h1>Hello LeetCoder</h1>
        </div>
    );
}

const rootElement = document.getElementById("root");
ReactDOM.render(
    <StrictMode>
        <App />
    </StrictMode>,
    rootElement
);

import ReactDOM from "react-dom";
import React, { memo, StrictMode, useCallback, useEffect, useLayoutEffect, useMemo, useRef, useState } from "react";

/* -------------------------------------------- */

function Clicker() {
    const [clicks, setClicks] = useState(0);

    const onClick = () => {
        setTimeout(() => {
            setClicks(clicks + 1);
        }, 2000);
    };

    return (
        <>
            {clicks}
            <button onClick={onClick}>
                Increment
            </button>
        </>
    );
}

/* -------------------------------------------- */

function App() {
    return (
        <div className="App">
            <h1>Hello LeetCoder</h1>
        </div>
    );
}

const rootElement = document.getElementById("root");
ReactDOM.render(
    <StrictMode>
        <App />
    </StrictMode>,
    rootElement
);

const X = { a: 1, b: 2, c: 3, d: 4 }

function getProperty(obj, key){
    return obj[key];
}

getProperty(X, 'a');
getProperty(X, 'm'); // Argument of type '"m"' is not assignable to parameter of type '"a" | "b" | "c" | "d"'
getProperty({ asd: 123 }, 'a'); // Argument of type '"a"' is not assignable to parameter of type '"asd"'

const sleep = (ms) => new Promise((resolve) => setTimeout(resolve, ms)); // заглушка

const someMethod = (nums) => {
    const results = [];
    nums.forEach(async (el) => {
        await sleep(500) // ждем какой-то асинк метод (на практике был бы запрос к серверу)
        results.push(el * 2);
    });
    return results;
}

const start = () => {
    const results = someMethod([1,2,3]);
    console.log(results);
}

// start();

setTimeout(()=>{
    console.log("timeOut");
}, 0)

console.log(1);

new Promise(resolve => {
    console.log("Promise");
    setTimeout(()=>{
        console.log("777");
        resolve()
    },0)
}).then(() => {
    console.log("then1");
}).then(() => {
    console.log("then2");
})

console.log(4);

setTimeout(()=>{
    console.log("timeOut2");
},0)