bcherny

type $Arguments<F> = $Call<<A: $ReadOnlyArray<mixed>>((...A) => mixed) => A, F>;
type $MethodArguments<O: {}, F: $Keys<O>> = $Arguments<
  $NonMaybeType<$ElementType<O, F>>,
>;

bcherny

• https://www.johnwdefeo.com/articles/seo-for-engineers
• https://www.elephate.com/blog/javascript-seo-backfire-hulu-com-case-study/
• https://ahrefs.com/blog/google-advanced-search-operators/#find-indexation-errors

bcherny

/*

Nice things about this approach:

- No need to expose $refs to users. Just use regular IDs instead.
- No need for double-composition (just compose React components, not queries).
- Composition becomes less magical (since we're passing regular IDs around).
- Collapse Query and Fragment concepts into Query.
- Take advantage of existing template strings to pass in query variables.

bcherny

let called = false;
// this 'scope' is safe to interact with the React component,
// rendering and clicking as you please
await render(
  <App
    callback={() => {
      called = true;
    }}
  />,
  document.body

bcherny

/*

Results of a few runs:

$ node ./index.js
{
  "a": 1000
}
$ node ./index.js
{

bcherny

let {readFile} = require('fs')

let tally = {ab: 0, ba: 0}
let globalDone = 0
let COUNT = 1000

for (let x = 0; x < COUNT; x++) {

  let result = ''
  let done = 0

bcherny

type Option<T> = Some<T> | None

type Some<T> = {
  flatMap<U>(f: (value: T) => None): None
  flatMap<U>(f: (value: T) => Some<U>): Some<U>
  flatMap<U>(f: (value: T) => Option<U>): Option<U>
  getOrElse(value: T): T
}

type None = {

bcherny

function Option<T>(value?: null | undefined): None
function Option<T>(value: T): Some<T>
function Option<T>(value?: T): Option<T> {
  if (value == null) {
    return new None
  }
  return new Some(value)
}

interface Option<T> {

bcherny

Using Webpack + Uglify + treeshaking + commonjs (not es2015).

Setup: https://github.com/bcherny/rxjs-filesize-repro

Package	import	Size	Size (gzipped)
rxjs	Observable	12kb	3kb
react	Component	9kb	4kb
react-dom	render	100kb	33kb
lodash	map	20kb	6kb

bcherny

Thoughtstream: GC'able Undux stores

• Stores would no longer be singletons
• No top level createStore
• Instead, use store factory that creates store instances
• Created for you as part of connect from an initial state

let withStore = connect({
 a: 1,