@fantastic-utils/memo

A memo library which can be used in many cases, this library is inspired by memoize-one, proxy-memoize, async-memoize-one, and have more feature to support different use cases.

Difference with others

memoize-one and proxy-memoize are great, but they are only for some general cases, as many tools and libraries are designed in a special way, so some corner case can't be handled correctly, so this library build up for solving this issue.

• memoize-one: use shallow compare as a straightforward way.
• proxy-memoize: is build on proxy-compare which author designed as a stateless library, and proxy-memoize use its markup key to compare old object and new object.

As many library now use the Proxy feature, and Proxy always work with Scope feature, so we can't always simply treat object as a immutable value, especially in some library design, maybe that's we wanted, so This library give an another choice to control the logic, not just a dead code.

Installation

npm install @fantastic-utils/memo

Usage

this library contains memo and memoAsync.

import { memo, memoAsync, original } from '@fantastic-utils/memo';

// Basic cache
const add = (a, b) => a + b;
const memoAdd = memo(add);
memoAdd(1, 2); // 3
memoAdd(1, 2); // 3 from cache

// Deep cache
const add = (objA, arrayB) => objA.a + objB[0];
const memoAdd = memo(add);
memoAdd({ a: 1 }, [2]); // 3
memoAdd({ a: 1 }, [2]); // 3 from cache

// Async cache
const add = async (a, b) => await (a + b);
const memoAdd = memoAsync(add);
await memoAdd(1, 2); // 3
await memoAdd(1, 2); // 3

// Shallow compare
const add = (objA, b) => objA.a + b;
const memoAdd = memo(add, { objectShallowCompare: true });
const obj = { a: 1 };
memoAdd(obj, 2); // 3
obj.a = 2;
memoAdd(obj, 2); // 3 from cache

// console log raw data, as argument is wrapped by proxy
const add = (objA, b) => {
  console.log(original(objA));
  return objA.a + b;
};

Use with React pure component

import { memo, original } from '@fantastic-utils/memo';

const TestComponent = memo((props) => {
  // Take care of console.log, as console.log will construct proxy values
  // use original to get the raw value.
  // Note that `.detail` will be marked as used
  console.log(original(props.detail));
  return (
    <>
      <h3>{props.detail.address}</h3>
    </>
  );
});

export default TestComponent;

Reference

// memo function
memo(fn, memo: MemoConfig): fn
// async memo function
memoAsync(fn, memo: MemoConfig): fn
// Get raw object, as arg are wrapped by proxy
original(arg): object

export interface MemoConfig {
  objectShallowCompare?: boolean;
  shouldCompare?: (args?: any[], cachedArgsCfg?: NormalizeArgCfg[]) => boolean;
  isChanged?: (args?: any[], cachedArgsCfg?: NormalizeArgCfg[]) => boolean;
}

/**
 * @param t The Type
 * @param v The normalized value
 * @param r The raw value
 * @param a The affected info
 */
export interface NormalizeArgCfg {
  t: string;
  v: unknown;
  r: unknown;
  a: Affected;
}

Advance Usage

shouldCompare

API: function(newArgs: any[], cachedArgsCfg: NormalizeArgCfg[]): boolean.

shouldCompare let user to determine whether to compare args with default compare logic or not,

import { memo } from '@fantastic-utils/memo';

const add = (a, b) => a + b;
const memoAdd = memo(add, {
  shouldCompare(newArgs, cachedArgCfg) {
    return newArgs[0] === 1;
  },
});
memoAdd(1, 2); // 3
memoAdd(1, 2); // 3 from cache
expect(memoAdd).toBeCalledTimes(1); // only call once

isChanged

API: function(newArgs: any[], cachedArgsCfg: NormalizeArgCfg[]): boolean.

isChanged is a high level api than shouldCompare to control all compare logic.

import { memo } from '@fantastic-utils/memo';

const add = (a, b) => a + b;
const memoAdd = memo(add, {
  isChanged(newArgs, cachedArgCfg) {
    return newArgs[0] === 1;
  },
});
memoAdd(1, 2); // 3
memoAdd(1, 2); // 3 from re-run function
expect(memoAdd).toBeCalledTimes(2); // call twice

Difference between shouldCompare and isChanged

The biggest difference between shouldCompare and isChanged is that shouldCompare control how to use cache, and isChanged control how to compare. sometimes shouldCompare used to improve performance, and isChanged used to customize compare logic.

Please refer to above code see the compare detail.

Performance compare

Benchmark code pls refer to __benchmark__ folder.

@fantastic-utils/memo deep x 82,670,951 ops/sec ±2.32% (85 runs sampled)
proxy-memoize deep x 779,043 ops/sec ±3.83% (85 runs sampled)
memoize-state deep x 22,624,061 ops/sec ±1.82% (81 runs sampled)

Fastest is @fantastic-utils/memo deep

@fantastic-utils/memo shallow x 26,180,311 ops/sec ±1.04% (89 runs sampled)
proxy-memoize shallow x 1,120,131 ops/sec ±1.29% (86 runs sampled)
memoize-one shallow x 17,569,314 ops/sec ±1.66% (83 runs sampled)
memoize-state shallow x 18,697,192 ops/sec ±3.24% (86 runs sampled)

Fastest is @fantastic-utils/memo shallow

Develop

$ npm install

$ npm run dev
$ npm run build

LICENSE

MIT