See your most expensive requires

require.js

'use strict'

const Module = require('module')
const original = Module.prototype.require

const items = new Map()

function sorter(a, b) {
  if (a < b) return -1
  if (a > b) return 1
  return 0
}

function addItem(ms, name) {
  const item = items.get(ms) || new Set()
  item.add(name)
  items.set(ms, item)
}

Module.prototype.require = function(id) {
  const parent = this.parent
  const n = `  -> ${this.id}`
  const parentName = getParent(parent)
  const name = `require "${id}" from \n${n}\n${parentName}`
  const start = process.hrtime()
  const result = original.call(this, id)
  const duration = process.hrtime(start)
  const ms = duration[0] * 1000 + duration[1] / 1e6
  addItem(ms, name)
  return result
}

setImmediate(() => {
  const sortedKeys = Array.from(items.keys()).sort(sorter)
  for (const key of sortedKeys) {
    for (const item of items.get(key)) {
      console.log('%sms \n', key, item)
    }
  }
})

function getParent(parent) {
  if (parent) {
    let idx = 1
    const buf = []
    while (idx++) {
      buf.push(`  -> ${parent.id}`)
      parent = parent.parent
      if (!parent) return buf.join('\n')
      if (idx > 10) break
    }
    return buf.join('\n')
  }
  return '  -> [none]'
}

run.sh

node -r ./require.js <entrypoint>