jkrems

'use strict';

function calculate(expression) {
  // [...]
}

jkrems

Module Resolution & Format Lookup

Motivating Examples

• A package (react-dom) has a dedicated entrypoint `react-dom/server for code that isn't compatible with a browser environment.
• A package (angular) exposes multiple independent APIs, modeled via import paths like angular/common/http.
• A package (lodash) allows to import individual functions, e.g. lodash/map.
• A package is exclusively exposing an ESM interface.
• A package is exclusively exposing a CJS interface.
• A package is exposing both an ESM and a CJS interface.

jkrems

Moving to async/await

waterfall

function before(cb) {
  waterfall(
    f1,
    f2,
 cb

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'use strict';

const ivm = require('isolated-vm');

function handleParseJob(code) {
  return new ivm.ExternalCopy(JSON.parse(code), { transferOut: true });
}

function transferInExternalCopy(copy) {
  return copy.copy({ transferIn: true });

jkrems

Modules - History & Future

History

• Early work by Ihab Awad (Google) and Kris Kowal (FastSoft)
  • https://twitter.com/kriskowal/status/943547614158450688
  • Hermetic eval presentation: https://docs.google.com/presentation/d/1KlPxgocvzpTq44KTF4xZ6TnzGRsy628hP5he7bXVB3I/edit#slide=id.i0
• 2009-09: 2nd draft of module strawman, still very close to "closures as modules", export x = 42
  • https://esdiscuss.org/topic/hermetic-evaluation-modules-strawman

• https://docs.google.com/document/u/1/pub?id=1hNv1SHh_v_6nD1QBd6pySUJ2U5roAELzW5cqD2tt_WM

jkrems

node_modules

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// V8 6.2 required
'use strict';

const fs = require('fs');
const { Session } = require('inspector');
const { promisify } = require('util');

const session = new Session();
if (session != null) {
  session.connect();

jkrems

Getting seconds or milliseconds since January 1, 1970, 00:00:00 GMT in various languages

Second-Native

C (1972)

// ms
struct timespec spec;
clock_gettime(CLOCK_REALTIME, &spec);

jkrems

Installing project specific tools like react-native globally is yucky. Even when it's just thin CLI wrappers. Unfortunately react-native actively breaks local npm binaries by forcing a broken bin stub into each project. So if you added ./node_modules/.bin to your $PATH, every attempt of running react-native inside of a project will fail with an annoying (and wrong) claim that you installed react-native globally.

The easiest solution I found so far:

• npm install --save react-native-cli in your React Native project

jkrems

Gofer v3

The following is just a proposal & not yet finished.

The biggest change in 3.x is that gofer no longer uses request behind the scenes. Also we're trying to align the interface more closely with fetch. Whenever we return a promise, it will be Bluebird-flavored.

Simple fetch-style usage: