GeezerVison is showing github.com — Memoization/JavaScript/5-sha.js at master · HowProgrammingWorks/Memoization

Expand file tree

5-sha.js

Copy path

More file actions

42 lines (32 loc) · 899 Bytes

Copy path

42 lines (32 loc) · 899 Bytes

Copy raw file

Download raw file

Open symbols panel

Edit and raw actions

'use strict';

const crypto = require('node:crypto');

const argKey = (x) => `${x.toString()}:${typeof x}`;

const generateKey = (args) => {

const key = args.map(argKey).join('|');

return crypto.createHash('sha256').update(key).digest('hex');

};

const memoize = (fn) => {

const cache = {};

return (...args) => {

const key = generateKey(args);

const val = cache[key];

if (val) return val;

const res = fn(...args);

cache[key] = res;

return res;

};

// Usage

const sumSeq = (a, b) => {

console.log('Calculate sum');

let r = 0;

for (let i = a; i < b; i++) r += i;

return r;

};

const mSumSeq = memoize(sumSeq);

console.log('First call mSumSeq(2, 5)');

console.log('Value:', mSumSeq(2, 5));

console.log('Second call mSumSeq(2, 5)');

console.log('From cache:', mSumSeq(2, 5));

console.log('Call mSumSeq(2, 6)');

console.log('Calculated:', mSumSeq(2, 6));