Cache a function

Cache_Function.markdown

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A Pen by Mingkai Cao on CodePen.

License.

script.js

function cache(fn) {
  
  let cache = new Map();
  let cachedFn = function(...args) {
    const key = args.join('.');
    if (cache.has(key)) {
      return cacha.get(key);
    }
    const res = fn.apply(this, args);
    cache.set(key, res);
    return res;
  }
  cachedFn.cache = cache;
  return cachedFn;
}


// test
let cost = function(a, b, c) {
  let res = 0;
  for (let i = 0; i < 100; i++) {
    res += a * i + b + c;
  }
  return res;
}
let cached = cache(cost);
console.time("2, 2, 2: 1st time");
console.log(cached(2,2,2));
console.timeEnd("2, 2, 2: 1st time");

console.time("2, 2, 2: 2nd time");
console.log(cached(2,2,2));
console.timeEnd("2, 2, 2: 2nd time");

console.time("3,3,3: 1st time");
console.log(cached(2,2,2));
console.timeEnd("3,3,3: 1st time");

console.time("3,3,3: 2nd time");
console.log(cached(2,2,2));
console.timeEnd("3,3,3: 2nd time");

console.log(cached.cache);

cache a function