复制
1const add = () => {
2  const cache = {};
3  return num => {
4    if (num in cache) {
5      return `From cache! ${cache[num]}`;
6    } else {
7      const result = num + 10;
8      cache[num] = result;
9      return `Calculated! ${result}`;
10    }
11  };
12};
13
14const addFunction = add();
15console.log(addFunction(10));
16console.log(addFunction(10));
17console.log(addFunction(5 * 2));