Behzod | IT blog

#interview #js
Funksiya bor, elementlarni nusxalab qaytaradaigan funksiya yaratish kerak?

 duplicate([1, 2, 3]) //[1, 2, 3,1, 2, 3,]

Yechim:

const duplicate = args =>  [...args, ...args];

Bu yerda array spread operatoridan foydalanildi

58 viewsedited 11:42

Behzod | IT blog

#interview #js

Quyidagi kod qanday natija chiqaradi?

let b = {};
let c;
b.b = 1;
c = b;
c.b = 2;
console.log(b.b);
console.log(c.b);

61 views12:20

Behzod | IT blog

#interview #js Quyidagi kod qanday natija chiqaradi? let b = {}; let c; b.b = 1; c = b; c.b = 2; console.log(b.b); console.log(c.b);

Javob:

let b = {};       // b nomli yangi bo'sh obyekt yaratadi 
let c;            // undefined qiymati bilan yangi o'zgaruvchi yaratadi 
b.b = 1;          //  b obyektning b propertysiga 1 qo'yadi
c = b;            // c ga b ni tenglaydi, lekin ikkala o'zgaruvchi ham bitta obyektga ulanadi 
c.b = 2;          // natiajada ikklasida ham bir xil qiymat paydo bo'ladi chunki bitta obyekt
console.log(b.b); // 2
console.log(c.b); // 2

64 views12:24

Behzod | IT blog

#interview #js

Quyidagi kod qanday natija chiqaradi?

var a = { name: 'Vasya' };
var b = { name: 'Vasya' };
console.log(a === b);

57 viewsedited 12:09

Behzod | IT blog

#interview #js Quyidagi kod qanday natija chiqaradi? var a = { name: 'Vasya' }; var b = { name: 'Vasya' }; console.log(a === b);

Javob: false
Chunki bu 2 xil obyekt hisoblanadi, bu primitiv tip emas

57 views12:10

Behzod | IT blog

#interview #js

Quyidagi kod qanday natija chiqaradi?

function f1(a, b) {
  console.log(a, b);
}

let f2 = f1.bind(null, 'foo');

f2('bar', 'baz');

61 viewsedited 12:29

Behzod | IT blog

#interview #js Quyidagi kod qanday natija chiqaradi? function f1(a, b) { console.log(a, b); } let f2 = f1.bind(null, 'foo'); f2('bar', 'baz');

Javob:

//foo, bar

Chunki bind() orqali f2 nomli yangi funksiya yaratiladi, 'foo' yuqori darajaga ega bo'ladi, bar biz esa 2,3- argument sifatida ketadi

58 views12:31

Behzod | IT blog

#interview #js

Quyidagi kod qanday natija chiqaradi?

let name='rabbit'

function go(){
  let name="Forest"
  console.log(name)
}
name='Alice';
go()

58 views12:38

Behzod | IT blog

#interview #js Quyidagi kod qanday natija chiqaradi? let name='rabbit' function go(){ let name="Forest" console.log(name) } name='Alice'; go()

Javob:

// Forest

Global o'zgaruvchi ta'sir qilmaydi , lokal o'zgaruvchi ishlaydi funksiya ichida

58 views12:39

Behzod | IT blog

#interview #js
Skriptlarni sahifaga ulash (async, defer)

https://telegra.ph/Skriptlarni-sahifaga-ulash-async-defer-02-26

Telegraph

Skriptlarni sahifaga ulash (async, defer)

Zamonaviy vebsaytlarda skriptlar ko'pincha og'irroq bo'ladi HTML ga qaraganda, ularning yuklash hajmi kattaroq, va anchagina vaqt oladi. Qachonki brauzer HTMLni yuklashni boshlasa va <script>...</script> tegiga duch kelsa, brauzer darhol HTML DOM ni yuklashni…

63 viewsedited 02:51

Behzod | IT blog

#interview #js

Quyidagi funksiyani yarating?

add(2, 5); // Output: 7
add(2)(5); // Output: 7

Javob:

const add = (a, b) => {
  if (b !== undefined) return a + b;
  return c => a + c;
};

2-yechim:

function sum(a) {
  return function (b) {
    return a + b; // takes "a" from the outer lexical environment
  };
}

Yanada qiyinrog'i:

console.log(sum(1)(2).toString()); // 3
console.log(sum(1)(2)(3).toString()); // 6
console.log(sum(5)(-1)(2).toString()); // 6
console.log(sum(6)(-1)(-2)(-3).toString()); // 0
console.log(sum(0)(1)(2)(3)(4)(5).toString()); // 15


function sum(a) {
  let currentSum = a;

  function nextSum(b) {
    currentSum += b;
    return nextSum;
  }

  nextSum.toString = function() {
    return currentSum;
  };

  return nextSum;
}



function sum(a) {
  if (arguments.length == 2) {
    return arguments[0] + arguments[1];
  } else {
    return function (b) {
      return a + b;
    };
  }
}

console.log(sum(2, 3)); // Outputs 5sds
console.log(sum(2)(3)); // Outputs 5

62 viewsedited 05:33

Behzod | IT blog

#interview #js

Kengaytmani topadigan kod yozing.
Masalan:

getExtension("ferrf.ferf.fe.exe") // exe

Javob:

const getExtension = (fileName)=>{
if(typof filename !== 'string')
{
throw new Error('Invalid type')
}

const parts = filename.split(' .')
return parts.length == 1 ? null :parts[parts.length-1]
}

56 viewsedited 06:30

Behzod | IT blog

#interview #js
Quyidagi divlar jamlanmasining eng quyi chuqurligini toping?

 <div id="app">
      <div>
        <div>
          <div></div>
        </div>
      </div>
      <div>
        <div>
          <div>
            <div></div>
          </div>
        </div>
      </div>
    </div>

Javob:

const app = document.querySelector('#app');

const treeDepth = (divel, currentLevel) => {
  if (divel.children.length === 0) return currentLevel;
  currentLevel += 1;
  let maxDepth = currentLevel;
  Array.from(divel.children).forEach(element => {
    maxDepth = Math.max(treeDepth(element, currentLevel), maxDepth);
  });
  return maxDepth
};
console.log(treeDepth(app, 0));

60 views08:57

Behzod | IT blog

#interview #js

1. Nuxt js va Vue js farqi
2. SSR nima
3. Child componentdan Parentga
4. Vue js lifecycle hooklar sanang

54 views04:49

Behzod | IT blog

#interview #js

function reduce(arr, callback, initVal) {
  let acc = initVal === 'undefined' ? 'undefined' : 0;
  for (let i = 0; i < arr.length; i++) {
    if (acc !== 'undefined') {
      acc = callback(acc, arr[i], i, arr);
    } else {
      acc = arr[i];
    }
  }
  return acc
}
const numbers=[1,2,3]
console.log(reduce(numbers,function(acc,val){
  return acc+val
},0))

56 viewsedited 07:51

Behzod | IT blog

function map(arr, callback) {
  const newArr = [];
  for (let i = 0; i < arr.length; i++) {
    const result = callback(arr[i], i, arr);
    newArr.push(result);
  }
  return newArr;
}

60 views07:52

Behzod | IT blog

function customSome(callback) {
  for (let i = 0; i < this.length; i++) {
    if (callback(this[i], i, this)) {
      return true;
    }
  }
  return false;
}

Array.prototype.customSome = customSome;

64 views07:54

Behzod | IT blog

function filter(array, callback) {
  const filteredArray = [];
  for (let i = 0; i < array.length; i++) {
    if (callback(array[i], i, array)) {
      filteredArray.push(array[i]);
    }
  }
  return filteredArray;
}

66 views07:55

Behzod | IT blog

Quyidagi funksiyani bir necha marta chaqirish orqali, counterni increment qilishni, yo'li self invoked funksiyadan foydalanish

const add = (function () {
  let counter = 0;
  return function () {counter += 1; return counter}
})();

add();
add();
add();
console.log(add())

58 viewsedited 11:46

Behzod | IT blog

for (var i = 1; i <= 10; i++) {
  function foo(x) {
    setTimeout(() => {
      console.log(x);
    }, 0);
  }
  foo(i);
}

52 views04:20

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