This is a package which provides a memoize function, as well as a TypeScript decorator which will memoize a class method.

import memoize from '@github/memoize' const fn = memoize(function doExpensiveStuff() { // Here's where you do expensive stuff! }) const other = memoize(function doExpensiveStuff() {}, { cache: new Map(), // pass your own cache implementation hash: JSON.stringify // pass your own hashing implementation })

• hash?: (...args: A) => unknown Provides a single value to use as the Key for the memoization. Defaults to JSON.stringify (ish).
• cache?: Map<unknown, R> The Cache implementation to provide. Must be a Map or Map-alike. Defaults to a Map. Useful for replacing the cache with an LRU cache or similar.

This package also includes a decorator module which can be used to provide TypeScript Decorator annotations to functions.

Here's an example, showing what you need to do:

import memoize from '@github/memoize/decorator' // ^ note: add `/decorator` to the import to get decorators class MyClass { @memoize() // Memoize the method below doThings() { } } const cache = new Map() class MyClass { @memoize({ cache }) // Pass options just like the memoize function doThings() { } }

Many memoize implementations exist. This one provides all of the utility we need at GitHub and nothing more. We've used a few various implementations in the past, here are some good ones:

• memoize
• mem
• lodash.memoize

npm install npm test 

Distributed under the MIT license. See LICENSE for details.