题解 | #Array.reduce#
Array.reduce
http://www.nowcoder.com/practice/213d0ef21cb841de8cf69fcc5ea60eb6
``` // 补全代码\n
Array.prototype._reduce = function(callback) {
let len = this.length;
if(len==0) throw 'typeError';
if(len == 1) return this[0];
let prev = this[0],next;
for(let i = 0; i < len-1;i++) {
next = this[i+1];
prev = callback(prev,next);
}
return prev;
}
