node-fetch-exercise.js

// require dependencies
const fs = require('fs');
const path = require('path');
const nodeFetch = require('node-fetch');
const assert = require('assert');

// declare constants
const START = Date.now();
const NOW = () => `${Date.now() - START} ms: `;
const REPORT_NAME = path.basename(__filename).replace('.js', '-report.txt');

// define logging function
const log = (msg) => {
  const cleanedMsg = msg.split(__dirname).join(' [ ... ] ');
  console.log(cleanedMsg);
  fs.appendFileSync('./' + REPORT_NAME, cleanedMsg + '\n');
};

// (re)initialize exercise report
fs.writeFileSync(REPORT_NAME, '');
log((new Date()).toLocaleString());


// begin main script


const URL = 'https://jsonplaceholder.typicode.com/comments?postId=1';


log(NOW() + 'fetching ' + URL + ' ...');

nodeFetch(URL)
  .then(res => {
    clearInterval(dotDotDot);
    log(NOW() + 'parsing response ...');
    return res.json()
  })
  .then(data => {
    log(NOW() + 'testing data ...')
    for (let i = 0; i < comments.length; i++) {
      log(NOW() + '... entry ' + i)
      try {
        assert.strictEqual(comments[i].postId, 3);
      } catch (err) {
        log(err.stack + '\n');
      }
      // or more simply
      assert.strictEqual(comments[i].postId, 3);
    };
    log(NOW() + '... done!');
  })
  .catch(err => error(err));


const dotDotDot = setInterval(() => {
  log(NOW() + '...');
}, 100);