flavorus / lru-memoize

A utility to provide LRU memoization for any js function

#lru-memoize

lru-memoize is a utility to provide simple memoization for any pure javascript function, using an LRU cache that prioritizes the most recently accessed values, and discards the "least recently used" (LRU) items when the size limit is reached. If your function has side effects or relies on some external state to generate its result, it should not be memoized.

Installation

npm install --save lru-memoize

Usage

Let's look at an example where we want to memoize a function that multiplies three numbers together, and we want to keep the last ten arguments -> value mappings in memory.

ES5

var memoize = require('lru-memoize');

var multiply = function(a, b, c) {
  return a * b * c;
}

multiply = memoize(10)(multiply);

module.exports = multiply;

ES6

import memoize from 'lru-memoize';

let multiply = (a, b, c) => a * b * c;

multiply = memoize(10)(multiply);

export default multiply;

API

memoize(limit:Integer?, equals:Function?, deepObjects:Boolean?)

Returns (Function) => Function.

-limit : Integer [optional]

The number of arguments -> value mappings to keep in memory. Defaults to 1.

-equals : Function [optional]

A function to compare two values for equality. Defaults to ===.

-deepObjects : Boolean [optional]

Whether or not to perform a deep equals on Object values. Defaults to false.

TypeScript

Type definitions can be found in index.d.ts which should automatically be picked up by the TypeScript compiler when this package is installed.