@reduxjs/toolkit/src/utils.ts

The official, opinionated, batteries-included toolset for efficient Redux development

import { produce as createNextState, isDraftable } from 'immer'

export function getTimeMeasureUtils(maxDelay: number, fnName: string) {
  let elapsed = 0
  return {
    measureTime<T>(fn: () => T): T {
      const started = Date.now()
      try {
        return fn()
      } finally {
        const finished = Date.now()
        elapsed += finished - started
      }
    },
    warnIfExceeded() {
      if (elapsed > maxDelay) {
        console.warn(`${fnName} took ${elapsed}ms, which is more than the warning threshold of ${maxDelay}ms. 
If your state or actions are very large, you may want to disable the middleware as it might cause too much of a slowdown in development mode. See https://redux-toolkit.js.org/api/getDefaultMiddleware for instructions.
It is disabled in production builds, so you don't need to worry about that.`)
      }
    },
  }
}

export function delay(ms: number) {
  return new Promise((resolve) => setTimeout(resolve, ms))
}

export class Tuple<Items extends ReadonlyArray<unknown> = []> extends Array<
  Items[number]
> {
  constructor(length: number)
  constructor(...items: Items)
  constructor(...items: any[]) {
    super(...items)
    Object.setPrototypeOf(this, Tuple.prototype)
  }

  static override get [Symbol.species]() {
    return Tuple as any
  }

  override concat<AdditionalItems extends ReadonlyArray<unknown>>(
    items: Tuple<AdditionalItems>,
  ): Tuple<[...Items, ...AdditionalItems]>
  override concat<AdditionalItems extends ReadonlyArray<unknown>>(
    items: AdditionalItems,
  ): Tuple<[...Items, ...AdditionalItems]>
  override concat<AdditionalItems extends ReadonlyArray<unknown>>(
    ...items: AdditionalItems
  ): Tuple<[...Items, ...AdditionalItems]>
  override concat(...arr: any[]) {
    return super.concat.apply(this, arr)
  }

  prepend<AdditionalItems extends ReadonlyArray<unknown>>(
    items: Tuple<AdditionalItems>,
  ): Tuple<[...AdditionalItems, ...Items]>
  prepend<AdditionalItems extends ReadonlyArray<unknown>>(
    items: AdditionalItems,
  ): Tuple<[...AdditionalItems, ...Items]>
  prepend<AdditionalItems extends ReadonlyArray<unknown>>(
    ...items: AdditionalItems
  ): Tuple<[...AdditionalItems, ...Items]>
  prepend(...arr: any[]) {
    if (arr.length === 1 && Array.isArray(arr[0])) {
      return new Tuple(...arr[0].concat(this))
    }
    return new Tuple(...arr.concat(this))
  }
}

export function freezeDraftable<T>(val: T) {
  return isDraftable(val) ? createNextState(val, () => {}) : val
}

export function getOrInsert<K extends object, V>(
  map: WeakMap<K, V>,
  key: K,
  value: V,
): V
export function getOrInsert<K, V>(map: Map<K, V>, key: K, value: V): V
export function getOrInsert<K extends object, V>(
  map: Map<K, V> | WeakMap<K, V>,
  key: K,
  value: V,
): V {
  if (map.has(key)) return map.get(key) as V

  return map.set(key, value).get(key) as V
}

export function getOrInsertComputed<K extends object, V>(
  map: WeakMap<K, V>,
  key: K,
  compute: (key: K) => V,
): V
export function getOrInsertComputed<K, V>(
  map: Map<K, V>,
  key: K,
  compute: (key: K) => V,
): V
export function getOrInsertComputed<K extends object, V>(
  map: Map<K, V> | WeakMap<K, V>,
  key: K,
  compute: (key: K) => V,
): V {
  if (map.has(key)) return map.get(key) as V

  return map.set(key, compute(key)).get(key) as V
}

export function promiseWithResolvers<T>(): {
  promise: Promise<T>
  resolve: (value: T | PromiseLike<T>) => void
  reject: (reason?: any) => void
} {
  let resolve: any
  let reject: any
  const promise = new Promise<T>((res, rej) => {
    resolve = res
    reject = rej
  })
  return { promise, resolve, reject }
}