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@swyxio
swyxio / createCtx-noNullCheck.tsx
Last active May 4, 2023 02:15
better createContext APIs with setters, and no default values, in Typescript. this is documented in https://github.com/typescript-cheatsheets/react-typescript-cheatsheet/blob/master/README.md#context
// create context with no upfront defaultValue
// without having to do undefined check all the time
function createCtx<A>() {
const ctx = React.createContext<A | undefined>(undefined)
function useCtx() {
const c = React.useContext(ctx)
if (!c) throw new Error("useCtx must be inside a Provider with a value")
return c
}
return [useCtx, ctx.Provider] as const
@sebmarkbage
sebmarkbage / Enhance.js
Last active February 10, 2025 06:23
Higher-order Components
import { Component } from "React";
export var Enhance = ComposedComponent => class extends Component {
constructor() {
this.state = { data: null };
}
componentDidMount() {
this.setState({ data: 'Hello' });
}
render() {