log-to-file/test.js

Log text to file (with timestamp)

// Import.
const log = require('./app');
const fs = require('fs');

// Remove log files.
fs.unlink('default.log', () => { });
fs.unlink('my-log.log', () => { });

// Log data.
(async () => {
  log('Some data to default log file "default.log".');
  await new Promise(resolve => setTimeout(resolve, 100));
  log('Another data to custom log file "my-log.log".', 'my-log.log');
  await new Promise(resolve => setTimeout(resolve, 100));
  log('Another data to custom log file "my-log.log" with delimiter "\\r\\n".', 'my-log.log', '\r\n');
  await new Promise(resolve => setTimeout(resolve, 100));
  log('Another data to custom log file "my-log.log" with delimiter "\\n-----\\n".', 'my-log.log', '\n-----\n');
  await new Promise(resolve => setTimeout(resolve, 100));
  log('Another data to custom log file "my-log.log".', 'my-log.log');
})();

// Wait 0,5 second and check default log file.
setTimeout(function () {
  fs.readFile('default.log', function (error, data) {
    if (error) console.log('Error:\n' + error);
    console.log('Default log file:\n' + data);
  });
}, 500);

// Wait 1 second and check custom log file.
setTimeout(function () {
  fs.readFile('my-log.log', function (error, data) {
    if (error) console.log('Error:\n' + error);
    console.log('Custom log file:\n' + data);
  });
}, 1000);