optimism

What is optimism?

The 'optimism' npm package is a library for memoizing asynchronous functions. It helps in caching the results of function calls and reusing them when the same inputs occur, thus improving performance by avoiding redundant computations.

What are optimism's main functionalities?

Memoizing Asynchronous Functions

This feature allows you to memoize asynchronous functions. The 'wrap' function from 'optimism' is used to wrap an async function, caching its results based on the input arguments. Subsequent calls with the same arguments will return the cached result instead of executing the function again.

const { wrap } = require('optimism');

const fetchData = wrap(async (url) => {
  const response = await fetch(url);
  return response.json();
});

// Usage
fetchData('https://api.example.com/data').then(data => console.log(data));
fetchData('https://api.example.com/data').then(data => console.log(data)); // This call will use the cached result

Custom Cache Key

This feature allows you to define a custom cache key for the memoized function. By providing a 'makeCacheKey' function, you can control how the cache key is generated based on the function's arguments.

const { wrap } = require('optimism');

const fetchData = wrap(async (url, params) => {
  const response = await fetch(url, { params });
  return response.json();
}, {
  makeCacheKey: (url, params) => `${url}-${JSON.stringify(params)}`
});

// Usage
fetchData('https://api.example.com/data', { id: 1 }).then(data => console.log(data));
fetchData('https://api.example.com/data', { id: 1 }).then(data => console.log(data)); // This call will use the cached result

Cache Expiration

This feature allows you to set an expiration time for the cache. By specifying the 'maxAge' option, you can control how long the cached result is valid. After the specified time, the cache will expire, and the function will be executed again to fetch new data.

const { wrap } = require('optimism');

const fetchData = wrap(async (url) => {
  const response = await fetch(url);
  return response.json();
}, {
  maxAge: 60000 // Cache expires after 60 seconds
});

// Usage
fetchData('https://api.example.com/data').then(data => console.log(data));
setTimeout(() => {
  fetchData('https://api.example.com/data').then(data => console.log(data)); // This call will fetch new data after cache expiration
}, 61000);

Other packages similar to optimism

memoizee

The 'memoizee' package provides a comprehensive solution for memoizing both synchronous and asynchronous functions. It offers more configuration options compared to 'optimism', such as cache size limits, primitive and deep equality checks, and more.

lru-cache

The 'lru-cache' package is a simple and efficient Least Recently Used (LRU) cache implementation. While it does not specifically target memoizing functions, it can be used to cache any kind of data, including function results. It is highly configurable and performant.

async-memoize

The 'async-memoize' package is designed specifically for memoizing asynchronous functions. It provides a straightforward API for caching async function results and supports custom cache keys and expiration times, similar to 'optimism'.

README

optimism

Composable reactive caching with efficient invalidation.