James Davies jamesddavies

The introduction to Reactive Programming you've been missing

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.

Magic words:

psql -U postgres

Some interesting flags (to see all, use -h or --help depending on your psql version):

-E: will describe the underlaying queries of the \ commands (cool for learning!)
-l: psql will list all databases and then exit (useful if the user you connect with doesn't has a default database, like at AWS RDS)

	let UserContext = React.createContext();

	class App extends React.Component {
	state = {
	user: null,
	setUser: user => {
	this.setState({ user });
	}
	};

	type Omit<T, K extends keyof T> = Pick<T, Exclude<keyof T, K>>;

	export function withAppContext<
	P extends { appContext?: AppContextInterface },
	R = Omit<P, 'appContext'>
	>(
	Component: React.ComponentClass<P> \| React.StatelessComponent<P>
	): React.SFC<R> {
	return function BoundComponent(props: R) {
	return (

	Promise.all([
	someThingThatReturnsAPromise(),
	otherThingThatReturnsAPromise(),
	lastThingThatReturnsAPromise()
	])
	.then( results =>
	{
	// this...
	const [first, second, third] = results;
	// ... instead of