Александр

- a9.forEach(function(elem) {
-   elem.toLowerCase();
- });
- 
- return a9;
+ return a9.map(function (elem) {
+   return elem.toLowerCase();
+ });

- a9.forEach(function(elem) {
-   elem.toLowerCase();
- });
+ a9.forEach(function(elem, i, arr) {
+   arr[i] = elem.toLowerCase();
+ });

- a9.forEach(function(elem) {
-   elem.toLowerCase();
- });
+ for (let index = 0; index < a9.length; index++) {
+   a9[index] = a9[index].toLowerCase();
+ }

const handleIndicatorChangeOne = (event) => {
  setValue(values => [Number(event.target.value) || '', values[1]]);
};

const handleIndicatorChangeTwo = (event) => {
  setValue(values => [values[0], Number(event.target.value) || '']);
};

• Isometric - часть 1
  
• Isometric - часть 2
  

const singleBusinessLogic = (() => {
  let isBusy = false;
  let promise = null;
  let done = null;
  let failure = null;
  
  return (id) => {
    if (!isBusy) {
      isBusy = true;
      promise = new Promise((resolve, reject) => ([done, failure] = [resolve, reject]));
      
      fetch(`https://jsonplaceholder.typicode.com/users/${id}`)
        .then(response => response.json())
        .then(done)
        .catch(failure)
        .finally(() => (isBusy = false));
    }
    
    return promise;
  };
})();

(async () => {
  console.log(await singleBusinessLogic(1)); // { ..., name: 'Leanne Graham', ... }
  console.log(await singleBusinessLogic(2)); // { ..., name: 'Leanne Graham', ... }
  setTimeout(async () => {
    console.log(await singleBusinessLogic(3)); // { ..., name: 'Clementine Bauch', ... }
    console.log(await singleBusinessLogic(4)); // { ..., name: 'Clementine Bauch', ... }
  });
})();

printNumbers(1, 5);

function printNumbers(from, to) {
  let current = from;
  let timerId = setTimeout(function go() {
    timerId = setTimeout(go, 1000);

    console.log(`current: ${current}`);
    
    if (current === to) {
      clearTimeout(timerId);
    }
    
    current++;
  }, 1000);
}

async function start() {
  const user = await getUser();
  
  console.log(user);
}

function getUser() {
  return fetch('https://jsonplaceholder.typicode.com/users/1')
    .then(response => response.json());
}

start();
/*
{
  id: 1,
  name: 'Leanne Graham',
  username: 'Bret',
  email: 'Sincere@april.biz',
  address: {
    street: 'Kulas Light',
    suite: 'Apt. 556',
    city: 'Gwenborough',
    zipcode: '92998-3874',
    geo: { lat: '-37.3159', lng: '81.1496' }
  },
  phone: '1-770-736-8031 x56442',
  website: 'hildegard.org',
  company: {
    name: 'Romaguera-Crona',
    catchPhrase: 'Multi-layered client-server neural-net',
    bs: 'harness real-time e-markets'
  }
}
*/

async function start() {
  const user = await getUser();
  
  console.log(user);
}

function getUser() {
  return new Promise((resolve, reject) => {
    const xhr = new XMLHttpRequest();
    
    xhr.open('GET', 'https://jsonplaceholder.typicode.com/users/1');
    xhr.addEventListener('load', () => {
      if (xhr.status === 200) {
        resolve(JSON.parse(xhr.response));
      } else {
        reject(xhr.response);
      }
    });
    
    xhr.send();
  });
}

function start() {
  getUser(user => {
    console.log(user);
  });
}

function getUser(callback) {
  const xhr = new XMLHttpRequest();

  xhr.open('GET', 'https://jsonplaceholder.typicode.com/users/1');
  xhr.addEventListener('load', () => {
    if (xhr.status === 200) {
      callback(JSON.parse(xhr.response));
    } else {
      callback(xhr.response);
    }
  });

  xhr.send();
}

start();

function start() {
  getUser((error, user) => {
    if (!error) {
      console.log(user);
    }
  });
}

function getUser(callback) {
  const xhr = new XMLHttpRequest();

  xhr.open('GET', 'https://jsonplaceholder.typicode.com/users/1');
  xhr.addEventListener('load', () => {
    if (xhr.status === 200) {
      callback(null, JSON.parse(xhr.response));
    } else {
      callback(new Error(xhr.response));
    }
  });

  xhr.send();
}

start();

[].toString() + true + false - null
"" + true // "true"
"" + true + false // "truefalse"
"" + true + false - null // NaN

true + false - null + [].toString()
1 + 0 // 1
1 + 0 - 0 // 1
1 + 0 - 0 + "" // "1"

document.getElementsByClassName('hypertrain-avatar')[0].getAttribute('style')

document.querySelector('.hypertrain-avatar').getAttribute('style')

const { src, dest, series } = require('gulp');
const through = require('through2');

const transformToJson = () => {
    return src('./src/settings.js')
        .pipe(through.obj((file, _, callback) => {
            const computed = require(file.path);

            file.extname = '.json';
            file.contents = Buffer.from(JSON.stringify(computed, null, 4));

            callback(null, file);
        }))
        .pipe(dest('./dist'));
};

module.exports.default = series(transformToJson);

- watch(['app/*.html']).оn('chenche', browserSync.reload);
+ watch(['app/*.html'], done => {
+     browserSync.reload();
+     done();
+ });

const lang = 'ru';

for (const key in languagesText[lang]) {
	document.querySelectorAll(`[data-translate="${key}"]`).forEach(element => element.textContent = languagesText[lang][key]);
}

.event {
  width: 300px;
  height: 100px;
  
  &__caption {
    color: blue;
  }

  &__description {
    color: green;
  }
}

@media screen and (max-width: 768px) {
    .event {
        &__caption {
            color: red;
        }
    }
}

.event {
  width: 300px;
  height: 100px;
  
  &__caption {
    color: blue;
    
    @media screen and (max-width: 768px) {
      color: red;
    }
  }

  &__description {
    color: green;
  }
}

const button = document.querySelector('.reset');
button.addEventListener('click', () => {
    document.querySelectorAll('.active').forEach(element => element.classList.remove('active'));
});

<button type="button" class="reset">сброс цвета</button>

const format = (date) => {
  const formatted = date.toLocaleString('ru-RU', {
    weekday: 'long',
    day: 'numeric',
    month: 'long',
  });
  
  return `${formatted[0].toUpperCase()}${formatted.slice(1)}`;
};

const today = Date.now();
const day = 24 * 60 * 60 * 1000;
const tomorrow = format(new Date(today + day));
const dayAfterTomorrow = format(new Date(today + day * 2));

console.log(tomorrow); // 'Вторник, 6 июля'
console.log(dayAfterTomorrow); // 'Среда, 7 июля'

const formatter = new Intl.DateTimeFormat('ru-RU', {
    weekday: 'long',
    day: 'numeric',
    month: 'long',
});

const format = (date) => {
  const formatted = formatter.format(date);
  
  return `${formatted[0].toUpperCase()}${formatted.slice(1)}`;
};

const today = Date.now();
const day = 24 * 60 * 60 * 1000;
const tomorrow = format(new Date(today + day));
const dayAfterTomorrow = format(new Date(today + day * 2));

console.log(tomorrow); // 'Вторник, 6 июля'
console.log(dayAfterTomorrow); // 'Среда, 7 июля'

document.querySelectorAll('ul li a').forEach((link, index) => {
   link.addEventListener('click', () => {
       console.log('Index is', index);
   });
});

document.querySelectorAll('a').forEach(link => {
   link.addEventListener('click', event => {
       const parent = event.target.closest('li');
       if (parent !== null) {
           const items = [...parent.parentElement.children];
           const index = items.indexOf(parent);
           console.log('Index is', index);
       }
   });
});