JavaScript 获取数组对象中某一值封装为数组

data = [["2000-06-05",116],["2000-06-06",129]];
var dateList = data.map(function (item) {
    return item[0];
});
console.log(dateList);

==>["2000-06-05","2000-06-06"]

data=[{"prodDate": "2018-01-02","oilProdDaily": 1.68},{"prodDate": "2018-01-03","oilProdDaily": 1.68}]; 

var prodData=data.map(function (item) {
　　　　 return item[‘prodDate‘]; 
}); 
console.log(prodData); 

==>["2018-01-02","2018-01-03",...]