Сергей Соколов

function verify(text) {
  const buffer = [];
  const valid = '()[]{}';

  for (let i = 0, len = text.length; i < len; i++) {
    const c = text[i];
    const idx = valid.indexOf(c);
    if (-1 === idx) continue; // не скобка
    if (idx & 1) { // закрывающая (нечет)
      if (0 === buffer.length) return false;
      if (valid.indexOf(buffer.pop()) + 1 !== idx) return false;
    } else { // открывающая
      buffer.push(c);
    }
  }
  
  return buffer.length === 0;  
}

(()=>{
const tests = [
  ["a(b)", true         ],
  ["[{}]", true         ],
  ["[(]", false         ],
  ["}{", false          ],
  ["z([{}-()]{a})", true],
  ["", true             ],
  ["(((}", false        ],
];

return JSON.stringify(
  tests.map(t => (verify(t[0]) === t[1] ? 'OK' : 'FAIL' ) + ': ' + t[0])
  , null,  
  2
);
})()


/*
[
  "OK: a(b)",
  "OK: [{}]",
  "OK: [(]",
  "OK: }{",
  "OK: z([{}-()]{a})",
  "OK: ",
  "OK: (((}"
]
*/

const token = 'xxxxxx';
var myHeaders = new Headers();
myHeaders.append('x-access-token', token);

var myInit = { method: 'GET',
               headers: myHeaders,
               mode: 'cors',
               cache: 'default' };

var myRequest = new Request('http://api.travelpayouts.com/v2/prices/latest', myInit);

fetch(myRequest)
  .then(res => res.json())
  .then(data => console.log(data))

const http = require("http");

const token = '321d6a221f8926b5ec41ae89a3b2ae7b';
const url = 'http://api.travelpayouts.com/v2/prices/latest';

http.get(
  url,
  {
      headers: {
      'x-access-token': token
      }
  },
  (res) => {
    const { statusCode } = res;
    const contentType = res.headers['content-type'];
  
    let error;
    if (statusCode !== 200) {
      error = new Error('Request Failed.\n' +
                        `Status Code: ${statusCode}`);
    } else if (!/^application\/json/.test(contentType)) {
      error = new Error('Invalid content-type.\n' +
                        `Expected application/json but received ${contentType}`);
    }
    if (error) {
      console.error(error.message);
      // Consume response data to free up memory
      res.resume();
      return;
    }
  
    res.setEncoding('utf8');
    let rawData = '';
    res.on('data', (chunk) => { rawData += chunk; });
    res.on('end', () => {
      try {
        console.log("raw data:", rawData);
        
        const parsedData = JSON.parse(rawData);
        console.log(parsedData);
      } catch (e) {
        console.error(e.message);
      }
    });
  }
  
).on('error', (e) => {
  console.error(`Got error: ${e.message}`);
});