Memily

Javascript memoization library. Wrap your computationally expensive functions with memily so that the results of calls are cached.

Browser Compatibility

This package is dependendent on the ES6 Map feature, which is available in most modern browsers. Consider using a polyfill such as core-js for legacy browser support.

Installation

Install memily to your project by running:

npm install --save memily

Or if you use Yarn:

yarn add memily

Then, import memily into your project like this:

import memily from 'memily';

Examples

Basic Usage

import memily from 'memily';
 
function squareRoot(num) {
    console.log('Hello world!');
    return Math.sqrt(num);
}
 
const squareRootMemoized = memily(squareRoot);
 
squareRootMemoized(4); // console.log: 'Hello world!'
squareRootMemoized(4); // ...
squareRootMemoized(4); // ...
squareRootMemoized(9); // console.log: 'Hello world!'

Caching for a finite time using maxAge option.

function squareRoot(num) {
    console.log('Hello world!');
    return Math.sqrt(num);
}
 
const squareRootMemoized = memily(squareRoot, { maxAge: 100 });
 
Promise.resolve()
    .then(() => squareRootMemoized(4)) // console.log: 'Hello world!'
    .then(() => squareRootMemoized(4)) // ...
    .then(() => new Promise(resolve => setTimeout(resolve, 200)))
    .then(() => squareRootMemoized(4)); // console.log: 'Hello world!'

Caching against a custom key using the cacheKey option.

const steveHolt = {
    id: 1,
    firstName: 'Steve',
    surname: 'Holt',
};
 
const tobiasFunke = {
    id: 2,
    firstName: 'Tobias',
    surname: 'Funke',
};
 
function getFullNameString(user) {
    console.log('Hello world!');
    return `${user.firstName} ${user.surname}`;
}
 
const getFullNameStringMemoized = memily(getFullNameString, {
    cacheKey: user => user.id,
});
 
getFullNameStringMemoized(steveHolt); // console.log: 'Hello world!'
getFullNameStringMemoized(steveHolt); // ...
getFullNameStringMemoized(tobiasFunke); // console.log: 'Hello world!'
getFullNameStringMemoized(tobiasFunke); // ...

Flushing the memoization cache

import { flush } from 'memily';
 
flush();

Flow Types

Memily comes with Flow types built in. No flow-typed installation required.

License

This project is licensed under the MIT License - see the LICENSE.md file for details

Acknowledgements

Memily was heavily inspired and influenced by sindresorhus's mem package.