Timestamp standard input with relative timestamp and less noise using node.js

readme.md

Pretty formatter with relative time stamp, inspired by moreutils ts but with less noise, print only changes :)

Install

Save file

chmod +x ts.js

Example of usage

For example for express app that use debug and frontail and with colors:

DEBUG_COLORS=yes DEBUG="*,-follow-redirects" npm run serve:ssr 2>&1| ./ts.js | frontail --port 8888 -

Or just in console:

21:55 $ DEBUG_COLORS=yes DEBUG="*,-follow-redirects" npm run serve:ssr 2>&1 | ./ts.js 
[21:02  2.246  +293] 
[        .255    +0] > node dist/server
[                  ] 
[21:02  3.133  +878]   express:router:route new '/all' +0ms
[        .134    +1]   express:router:layer new '/all' +5ms
[        .135    +1]   express:router:route get '/all' +2ms
[        .136    +1]   express:router:layer new '/' +0ms
[        .136    +0]   express:router:route new '/cache' +1ms
[                  ]   express:router:layer new '/cache' +0ms
[                  ]   express:router:route get '/cache' +0ms
[        .138    +2]   express:router:layer new '/' +0ms
[        .138    +0]   express:router:route new '/clear-api-cache' +0ms
[                  ]   express:router:layer new '/clear-api-cache' +0ms
[        .141    +3]   express:router:route post '/clear-api-cache' +0ms
[        .141    +0]   express:router:layer new '/' +0ms
[                  ]   express:router:route new '/precache' +0ms
[                  ]   express:router:layer new '/precache' +1ms
[                  ]   express:router:route post '/precache' +0ms
[                  ]   express:router:layer new '/' +0ms
[        .142    +1]   express:router use '/api' router +0ms
[        .142    +0]   express:router:layer new '/api' +0ms

ts.js

#!/usr/bin/env node

const readline = require('readline');

function formatDate(format, now, last){
  let delta = '+' + (now - last);
  format = format.replace('%r', pad(delta, 5, ' '));
  format = format.replace('%ss', pad(now.getSeconds(),2, ' '));
  format = format.replace('%S', pad(now.getSeconds(),2));
  format = format.replace('%.S', pad(now.getMilliseconds(), 3));
  format = format.replace('%s', now.getSeconds());
  format = format.replace('%dd', pad(now.getDate(),2));
  format = format.replace('%d', now.getDate());
  format = format.replace('%mm', pad(now.getMinutes(),2));
  format = format.replace('%m', now.getMinutes());
  format = format.replace('%MM', pad(now.getMonth()+1,2));
  format = format.replace(/%M(?![ao])/, now.getMonth()+1);
  format = format.replace('%yyyy', now.getFullYear());
  format = format.replace('%YYYY', now.getFullYear());
  format = format.replace('%yy', (now.getFullYear()+"").substring(2));
  format = format.replace('%YY', (now.getFullYear()+"").substring(2));
  format = format.replace('%HH', pad(now.getHours(),2));
  format = format.replace('%H', now.getHours());
  return format;

  function zeroIfEqual(a, b) {
    return a == b ? ' '.repeat(a.length) : a;
  }

  function pad(n, width, z) {
    z = z || '0';
    n = n + '';
    return n.length >= width ? n : new Array(width - n.length + 1).join(z) + n;
  }
}

function zeroIfEqual(a, b) {
  return a == b ? ' '.repeat(a.length) : a;
}

const rl = readline.createInterface({
  input: process.stdin,
  crlfDelay: Infinity
});

let last = new Date();
let lastTimeStamp = '';
let lastDelta = '';

// Read line by line and print timestamp but only value
rl.on('line', (line) => {
  let now = new Date();
  let timeStamp = formatDate('%HH:%MM %ss', now, last);
  let delta = formatDate('.%.S %r', now, last);

  console.log('[' + zeroIfEqual(timeStamp, lastTimeStamp) +
              zeroIfEqual(delta, lastDelta) +
              '] ' + line);
  last = now;
  lastTimeStamp = timeStamp;
  lastDelta = delta;
});