给定一个函数 fn ,它返回一个新的函数,返回的函数与原始函数完全相同,只不过它确保 fn 最多被调用一次。

 

示例 1:

输入:fn = (a,b,c) => (a + b + c), calls = [[1,2,3],[2,3,6]]
输出:[{"calls":1,"value":6}]
解释:
const onceFn = once(fn);
onceFn(1, 2, 3); // 6
onceFn(2, 3, 6); // undefined, fn 没有被调用

示例 2:

输入:fn = (a,b,c) => (a * b * c), calls = [[5,7,4],[2,3,6],[4,6,8]]
输出:[{"calls":1,"value":140}]
解释:
const onceFn = once(fn);
onceFn(5, 7, 4); // 140
onceFn(2, 3, 6); // undefined, fn 没有被调用
onceFn(4, 6, 8); // undefined, fn 没有被调用

 

提示: