Builtin modules REQuire Durations

This library measures the duration of require() on Node.js' builtin modules.

$ npx breqd
...
  { moduleName: 'tty', duration: 3822 },
  { moduleName: 'diagnostics_channel', duration: 3410 },
  { moduleName: 'url', duration: 3151 }
]
File generated by breqd: breqd-node-v20.17.0-darwin-x64.json
Open it on https://ui.perfetto.dev!

Opening the generated file on https://ui.perfetto.dev looks like this.

import {
  ModuleDurationsMap,
  ModuleDuration,
  getModuleDurations,
  sortModuleDurations,
} from 'breqd';

const moduleDurations: ModuleDurationsMap = getModuleDurations();

const sortedModuleDurations: ModuleDuration[] = sortModuleDurations(moduleDurations);

console.log(sortedModuleDurations);
// [
//   { moduleName: 'repl', duration: 4989944 },
//   { moduleName: 'assert', duration: 3411434 },
//   { moduleName: 'http2', duration: 2925764 },
//   ...
// ]

• Returns ModuleDurationsMap:
  • index (string) - The module name.
  • value (number) - The duration of require() on the module in nanoseconds.

Measures the duration of require() on all builtin modules of the running Node.js process and returns it.

• moduleDurations (ModuleDurationsMap) - The module-duration object from getModuleDurations().
• Returns ModuleDuration[]:
  • moduleName (string) - The module name.
  • duration (number) - The duration of require() on the module in nanoseconds.

Returns a sorted array of all the builtin module require() durations in descending order of durations.

• moduleDurations (ModuleDuration[]) - The module-duration object from sortModuleDurations().
• Returns TEF[]:
  • name (string) - The builtin module name.
  • cat (string) - The event category.
  • ph (string) - The event type.
  • pid (number) - The process ID.
  • ts (number) - The tracing clock timestamp of the event.
  • dur (number) - The duration of require() on the module in microseconds.

Converts the sorted array of all the builtin module require() durations into Chrome's Trace Event Format, so that it can be viewed on https://ui.perfetto.dev.

It matters if you care about startup performance, like in your Electron app where you might be require()-ing a number of Node.js modules during startup. For example:

The https-proxy-agent module has over 65M weekly downloads and it takes ~75ms to require() v7.0.5 on my Intel macOS Sonoma 14.6.1 running Node.js v20.17.0. ~43ms, i.e., 57% of the total module loading time is spent in requiring just Node.js' own builtin modules! Wouldn't it be great to see this get improved?

The visualization has been generated by using the perftrace project.

MIT