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2623-Memoize.js
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2623-Memoize.js
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/*
Given a function fn, return a memoized version of that function.
A memoized function is a function that will never be called twice with the same inputs. Instead it will return a cached value.
You can assume there are 3 possible input functions: sum, fib, and factorial.
sum: accepts two integers a and b and returns a + b.
fib: accepts a single integer n and returns 1 if n <= 1 or fib(n - 1) + fib(n - 2) otherwise.
factorial: accepts a single integer n and returns 1 if n <= 1 or factorial(n - 1) * n otherwise.
*/
/**
* @param {Function} fn
*/
function memoize(fn) {
// memo:{arg: val,...}
const memos = {}
return function (...args) {
const key = JSON.stringify(args)
if (memos[key] !== undefined) {
} else {
const result = fn(...args)
memos[key] = result
}
return memos[key]
}
}
/**
* let callCount = 0;
* const memoizedFn = memoize(function (a, b) {
* callCount += 1;
* return a + b;
* })
* memoizedFn(2, 3) // 5
* memoizedFn(2, 3) // 5
* console.log(callCount) // 1
*/