memoization javascript
// a simple pure function to get a value adding 10
const add = (n) => (n + 10);
console.log('Simple call', add(3));
// a simple memoize function that takes in a function
// and returns a memoized function
const memoize = (fn) => {
let cache = {};
return (...args) => {
let n = args[0]; // just taking one argument here
if (n in cache) {
console.log('Fetching from cache');
return cache[n];
}
else {
console.log('Calculating result');
let result = fn(n);
cache[n] = result;
return result;
}
}
}
// creating a memoized function for the 'add' pure function
const memoizedAdd = memoize(add);
console.log(memoizedAdd(3)); // calculated
console.log(memoizedAdd(3)); // cached
console.log(memoizedAdd(4)); // calculated
console.log(memoizedAdd(4)); // cached