fast-memoize

What is fast-memoize?

The fast-memoize npm package is a high-performance memoization library that caches the results of function calls, so that the result can be quickly retrieved when the function is called again with the same arguments. This can significantly improve performance for functions with expensive computations or I/O operations that are called repeatedly with the same inputs.

What are fast-memoize's main functionalities?

Simple memoization

This feature allows you to memoize a simple function like the Fibonacci sequence. The memoized version of the function will remember the results of previous calls and return the cached result when the same input occurs again.

const memoize = require('fast-memoize');
const fibonacci = n => (n < 2 ? n : fibonacci(n - 1) + fibonacci(n - 2));
const memoizedFibonacci = memoize(fibonacci);
console.log(memoizedFibonacci(10));

Custom cache

This feature allows you to provide a custom cache implementation. By default, fast-memoize uses a plain JavaScript object as a cache, but you can replace it with any other object that follows the Map interface, such as a Map instance.

const memoize = require('fast-memoize');
const myCache = new Map();
const memoizedFn = memoize(fn, { cache: { create: () => myCache } });

Custom serializer

This feature allows you to provide a custom serializer for the arguments of the memoized function. By default, fast-memoize uses a serializer that can handle primitives and object references, but with a custom serializer, you can extend this to handle more complex serialization scenarios.

const memoize = require('fast-memoize');
const jsonSerializer = { serialize: JSON.stringify };
const memoizedFn = memoize(fn, { serializer: jsonSerializer });

Custom strategy

This feature allows you to provide a custom memoization strategy. fast-memoize comes with a default strategy that works well for most cases, but you can implement your own strategy for more control over how memoization is applied.

const memoize = require('fast-memoize');
const customStrategy = require('my-custom-strategy');
const memoizedFn = memoize(fn, { strategy: customStrategy });

Other packages similar to fast-memoize

lodash.memoize

lodash.memoize is a memoization function from the popular Lodash utility library. It is similar to fast-memoize but may not be as performance-focused. Lodash allows for custom cache implementations but is generally considered to be larger and more feature-rich than fast-memoize.

memoizee

memoizee is another npm package that offers memoization. It provides a rich set of features, including the ability to limit cache size, expire cached items, and primitive mode for arguments handling. It is more configurable than fast-memoize but might be slower due to its additional features.

mem

mem is a minimalist memoization library that can cache the results of functions with any type of arguments, not just primitives. It offers TTL (time-to-live) for cache entries and is designed to be simple and efficient, though it may not be as fast as fast-memoize for certain use cases.

README

fast-memoize

In computing, memoization is an optimization technique used primarily to speed up computer programs by storing the results of expensive function calls and returning the cached result when the same inputs occur again. — Wikipedia

This library is an attempt to make the fastest possible memoization library in JavaScript that supports N arguments.

There are already very popular solutions for this problem, but they are not fast enough or accept only one argument.

Installation

To use the library, install it through npm

npm install fast-memoize

To port it to Browser or any other (non CJS) environment, use your favorite CJS bundler. No favorite yet? Try: Browserify, Webmake or Webpack

Usage

const memoize = require('fast-memoize')

const fn = function (one, two, three) { /* ... */ }

const memoized = memoize(fn)

memoized('foo', 3, 'bar')
memoized('foo', 3, 'bar') // Cache hit

Custom cache

The fastest cache is used for the running enviroment, but it is possible to pass a custom cache to be used.

const memoized = memoize(fn, {
  cache: customCache
})

The custom cache must implement the following methods:

• get
• set
• has
• delete

Custom serializer

To use a custom serializer:

const memoized = memoize(fn, {
  serializer: customSerializer
})

The serializer is a function that receives one argument and outputs a string that represents it. It has to be a deterministic algorithm meaning that, given one input, it always give the same output.

Benchmark

There is already plenty of libraries that does memoization on JS world. underscore and lodash provides it, but they don't accept more than one argument. memoizee is a very well written library that supports N arguments, but is not even close on performance to lodash.

Below you can see a performance benchmark between some of the most popular libraries for memoization.

fast-memoize is faster than any other library but lodash. The reason why is that lodash does not support N arguments and is very optimized to that unique use case. But even though, fast-memoize is the library that supports N that comes closer to it.

To run the benchmark, clone the repo, install the dependencies and run npm run benchmark.

git clone [e-mail]:caiogondim/fast-memoize.git
cd fast-memoize
npm install
npm run benchmark

Support

Desktop browsers

Latest	8+	Latest	Latest	Latest	Latest	Latest

Mobile browsers

| | | | | | | | | --- | --- | --- | --- | --- | --- | --- | --- | --- | | Latest | 6+ | 4.0+ | 8+ | Latest | Latest | Latest |

Server

0.10+ ✔

Reference

• https://github.com/petkaantonov/bluebird/wiki/Optimization-killers#3-managing-arguments

Credits

• Icon by Mary Rankin from the Noun Project
• Bullet train ZSH theme