Progress bar in Node

progress.js

const readline = require('readline')

function drawProgress(current, total, promptLength = 25) {
  const percentComplete = current / total
  const visualPercent = Math.round(percentComplete * 100)
  const inProgressLength = Math.round(promptLength * percentComplete)
  const filledBar = rightPad('='.repeat(inProgressLength), ' ', promptLength)
  readline.cursorTo(process.stdout, 0)
  process.stdout.write(`[${filledBar}] ${visualPercent}%`)
}

function rightPad (str, char, length) {
  return (str.toString() + char.repeat(length)).substr(0, length)
}

let progress = 0
const timer = setInterval(() => {
  progress++
  drawProgress(progress, 100)
  if (progress === 100) {
    clearInterval(timer)
    console.log()
  }
}, 10)

// $ node progress.js
// [=========================] 100%