push()将无法在reduce()中按预期工作

Question

为什么不在a.push(b)我的Array.reduce()? a=a.push(b)where b字符串中工作,转为a整数.？!

 getHighestValuesInFrequency: function(frequency) {
 //Input:var frequency = {mats: 1,john: 3,johan: 2,jacob: 3};
 //Output should become ['John','jacob']

var objKeys = Object.keys(frequency);
var highestVal = objKeys.reduce((a,b)=>
            {highestVal = (frequency[b] > a)? frequency[b] : a;
             return highestVal;},0);

var winner = objKeys.reduce((a,b)=>
      { a = (frequency[b] === highestVal)? a.push(b) : a;
        return a},[]);

return winner;  
 }                                  

Answer 1

由于push()返回数组的新长度,因此您需要指定长度a.而不是条件运算符,使用if语句.

var winner = objKeys.reduce((a, b) => {
    if (frequency[b] === highestVal?) {
        a.push(b);
    }
    return a;
}, []);

Answer 2

push（）返回新的长度。您可以使用ES2015传播语法：

var Winner = objKeys.reduce（（a，b）=> {
    a =（frequency [b] === maximumVal）？[... a，b]：a;
    返回一个
}，[]）;