JavaScript/Cache/Memoize.js at patch-1 · MMABSOUT/JavaScript · GitHub

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/**

* @function memoize

* @description ->

* From [Wikipedia](https://en.wikipedia.org/wiki/Memoization),

* memoization is an optimization technique

* used primarily to speed up computer programs,

* by storing the results of expensive function calls

* and returning the cached result when the same inputs occur again

* This function is a first class objects,

* which lets us use it as [Higher-Order Function](https://eloquentjavascript.net/05_higher_order.html)

* and return another function

* @param {Function} func Original function

* @param {Map} cache - it's receive any cache DS which have get, set & has method

* @returns {Function} Memoized function

const memoize = (func, cache = new Map()) => {

const jsonReplacer = (_, value) => {

if (value instanceof Set) {

// if the value is Set it's converted to Array cause JSON.stringify can't convert Set

return [...value]

}

if (value instanceof Map) {

// if the value is Map it's converted to Object cause JSON.stringify can't convert Map

return Object.fromEntries(value)

}

return value

}

return (...args) => {

/**

* Arguments converted to JSON string for use as a key of Map - it's easy to detect collections like -> Object and Array

* If the args input is -> [new Set([1, 2, 3, 4]), {name: 'myName', age: 23}]

* Then the argsKey generate to -> '[[1,2,3,4],{"name":"myName","age":23}]' which is JSON mean string

* Now it's ready to be a perfect key for Map

const argsKey = JSON.stringify(args, jsonReplacer)

/**

* Checks if the argument is already present in the cache,

* then return the associated value / result

if (cache.has(argsKey)) {

return cache.get(argsKey)

}

/**

* If the argument is not yet present in the cache,

* execute original function and save its value / result in cache,

* finally return it

const result = func(...args) // spread all args

cache.set(argsKey, result)

return result

}

export { memoize }

JavaScript/Cache/Memoize.js at patch-1 · MMABSOUT/JavaScript · GitHub

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