export type NoInfer = [A][A extends any ? 0 : never] export type PartialKeys = Omit & Partial> export function memo, TResult>( getDeps: () => [...TDeps], fn: (...args: NoInfer<[...TDeps]>) => TResult, opts: { key: false | string debug?: () => boolean onChange?: (result: TResult) => void initialDeps?: TDeps }, ) { let deps = opts.initialDeps ?? [] let result: TResult | undefined function memoizedFunction(): TResult { let depTime: number if (opts.key && opts.debug?.()) depTime = Date.now() const newDeps = getDeps() const depsChanged = newDeps.length !== deps.length || newDeps.some((dep: any, index: number) => deps[index] !== dep) if (!depsChanged) { return result! } deps = newDeps let resultTime: number if (opts.key && opts.debug?.()) resultTime = Date.now() result = fn(...newDeps) if (opts.key && opts.debug?.()) { const depEndTime = Math.round((Date.now() - depTime!) * 100) / 100 const resultEndTime = Math.round((Date.now() - resultTime!) * 100) / 100 const resultFpsPercentage = resultEndTime / 16 const pad = (str: number | string, num: number) => { str = String(str) while (str.length < num) { str = ' ' + str } return str } console.info( `%c⏱ ${pad(resultEndTime, 5)} /${pad(depEndTime, 5)} ms`, ` font-size: .6rem; font-weight: bold; color: hsl(${Math.max( 0, Math.min(120 - 120 * resultFpsPercentage, 120), )}deg 100% 31%);`, opts?.key, ) } opts?.onChange?.(result) return result } // Attach updateDeps to the function itself memoizedFunction.updateDeps = (newDeps: [...TDeps]) => { deps = newDeps } return memoizedFunction } export function notUndefined(value: T | undefined, msg?: string): T { if (value === undefined) { throw new Error(`Unexpected undefined${msg ? `: ${msg}` : ''}`) } else { return value } } export const approxEqual = (a: number, b: number) => Math.abs(a - b) <= 1 export const debounce = ( targetWindow: Window & typeof globalThis, fn: Function, ms: number, ) => { let timeoutId: number return function (this: any, ...args: Array) { targetWindow.clearTimeout(timeoutId) timeoutId = targetWindow.setTimeout(() => fn.apply(this, args), ms) } }