Promise-cached NPM

promise-cached

Transparent cache for promise response for Node.js

Constraints

Whatever you are caching must be JSON seriazable.

Installation

This package is distributed as package in npm repository and can be installed using any node package manager.

Yarn

yarn add promise-cached

NPM

npm install promise-cached --save

Usage

This library provides wrapper for promise returning functions.

Basic usage

const wrapper = require("promise-cached");

// This is a very slow function that returns same response, every time, for same params
const sleepAndReturn = (message) => {
	return new Promise((resolve) => {
		setTimeout(() => {
			resolve(message);
		}, 1000);
	});
};

const options = {
	ttl: 10 * 1000 // Cache lasts for 10 seconds
};

// This function acts just like one above, exept it is very fast after the first time
const cachedFunction = wrapper("sleepAndReturn", sleepAndReturn, options);

cachedFunction("💪").then(() => {
	console.log("This took 1s");

	cachedFunction("💪").then(() => {
		console.log("This was instant! ");
	});
});

Speeding up existing functions

You can for example use this library to cache http responses.

const wrapper = require("promise-cached");

const options = {
	ttl: 10 * 1000 // Cache lasts for 10 seconds
};

const axios = require("axios");

const originalGet = axios.get;

axios.get = wrapper("axios.get", originalGet, options);