README.md

Triemoize

Efficient, reliable and memory leak free memoization using WeakMaps and tries

There are many memoization libraries out there. What this library tries to achieve is to be

• Efficient
• Reliable
• Memory leak free

For all this to work, you must always use immutable data as function arguments when you're calling the memoized function.

Installation

npm install --save triemoize

If you're using Yarn

yarn add triemoize

Usage

import memoize from 'triemoize'

// Create a pure function
const add = (a, b) = a + b

// Memoize it
const memoizedAdd = memoize(add)

memoizedAdd(1, 2) // The function was called
memoizedAdd(1, 2) // This time the result was taken from cache

Unlike from other memoization techniques like serialization, you can safely use huge objects or arrays as function arguments without worrying about performance or memory leaks. However, all the arguments you pass in must be immutable. Otherwise the memoization would not work correctly.

const getStringsLessThan = memoize((arrayOfStrings, num) => {
  return arrayOfStrings.filter(item => item.length < num)
})

const food = [
  'milk', 'bread', 'cheese', 'chocolate', 'potatoes', 'bacon',
  'butter', 'eggs', 'sausages', 'pork', 'yoghurt', 'apple'
]

getStringsLessThan(food, 6) // The function was called
getStringsLessThan(food, 6) // The result was taken from cache

What you should be aware of

Immutability

TODO

Function taking zero arguments

There is no need to memoize a function that takes zero arguments as it always returns the same result (provided it's pure). Therefore I decided not to support memoizing such functions.

Instead of this

const getHelloWorldString = memoize(() => 'hello world')

console.log(getHelloWorldString()) // undefined, not supported

simply do this :)

const helloWorldString = 'hello world'

console.log(helloWorldString) // hello world

Named arguments

Named arguments (using ES6 destructuring) are not supported. It would decrease performance, therefore I decided not to add this feature.

// Not supported in the moment

const add = ({ a, b }) = a + b
const memoizedAdd = memoize(add)

memoizedAdd({ a: 1, b: 2 }) // The function was called
memoizedAdd({ a: 1, b: 2 }) // Fail, the value was recomputed

How it works

TODO

Benchmarks

I created a set of benchmarks that tests the performance of triemoize on four different functions. For comparision I have tested the performance of fast-memoize as well.

You can try the benchmarks yourself

clone the repo

git clone https://github.com/ErikCupal/triemoize.git

install dependencies

yarn install

run benchmarks

npm run benchmark

Tested enviroment: Node v8.2.1, Windows 64bit, Intel Core i7-6820HQ 2.70 GHz, 16 GB RAM

Fibonacci

Function: const fibonacci = n => n < 2 ? n : fibonacci(n - 1) + fibonacci(n - 2)

Arguments: 15

Results:

METHOD	OPS/S
triemoize	32,781,123
fast-memoize	29,941,976

Add

Function: const add = (a, b) => a + b

Arguments: 1, 2

Results:

METHOD	OPS/S
triemoize	19,939,274
fast-memoize	803,437

Identity

Function: const identity = a => a

Preparation code: const obj = {}

Arguments: obj

Results:

METHOD	OPS/S
triemoize	7,721,084
fast-memoize	998,115

Get strings shorter than

Function: const getStringsShorterThan = (array, n) => array.filter(item => item.length <= n)

Preparation code: const food = ['milk', 'bread', 'wine', 'chocolate']

Arguments: food, 5

Results:

METHOD	OPS/S
triemoize	6,656,509
fast-memoize	554,577

License

MIT