SOURCE

let worker = {
  someMethod() {
    return 12;
  },

  slow(x) {
    // 可怕的 CPU 过载任务
    // alert("Called with " + x);
    return x * this.someMethod(); // (*)
  }
};

// console.log(slow(2))
function getUniq(args){
    return args.reduce((result, cur)=> result += `,${cur}`, '');
}
function withCache(func) {
    // 缓存
    const cache = new Map();
    
    return function(...args){
        const key = getUniq(args);
        if(cache.has(key)) {
            console.log('read from cache')
            return cache.get(key);
        } else {
            let result = func.apply(this, args);
            cache.set(key, result);
            return result;
        }

    }

}

const faster = withCache(worker.slow.bind(worker));
console.log(faster(2));
console.log(faster(2));