javascript - 搜索日期数组总是返回 -1

Question

这个问题已经有答案了:

Comparing date part only without comparing time in JavaScript (28 个回答)

已关闭 5 年前。

我创建了去年的日期数组，我需要在给定日期的数组中查找索引，但它返回 -1

但是，如果我对日期进行硬编码，这不太好，因为它不是动态的，它会工作并输出 331，这正是我所期望的

我该怎么做才能让它发挥作用？

// Returns an array of dates between the two dates
var getDates = function(startDate, endDate) {
  var dates = [],
    currentDate = startDate,
    addDays = function(days) {
      var date = new Date(this.valueOf());
      date.setDate(date.getDate() + days);
      return date;
    };

  while (currentDate <= endDate) {
    dates.push(currentDate);
    currentDate = addDays.call(currentDate, 1);
  }
  return dates;
};

var today = new Date(),
  last_year = new Date();

last_year.setMonth(last_year.getMonth() - 12);
last_year.setDate(last_year.getDate() + 1);

var dates = getDates(last_year, today);

var d = new Date(2017, 10, 31);

var test = dates.map(Number).indexOf(+d);
console.log(test); // dump -1

这有效......

dates = getDates(new Date(2017, 0, 4), new Date(2018, 12, 4));
d = new Date(2017, 10, 31);

test = dates.map(Number).indexOf(+d);
console.log(test); // dumps 331

Answer 1

因为您没有将小时、分钟设置为0，所以new Date()正在使用您需要清除的当前时间戳。

last_year.setMonth(last_year.getMonth() - 12);
last_year.setDate(last_year.getDate() + 1);
last_year.setHours(0,0,0,0); //this line is added

演示

// Returns an array of dates between the two dates
var getDates = function(startDate, endDate) {
  var dates = [],
    currentDate = startDate,
    addDays = function(days) {
      var date = new Date(this.valueOf());
      date.setDate(date.getDate() + days);
      return date;
    };

  while (currentDate <= endDate) {
    dates.push(currentDate);
    currentDate = addDays.call(currentDate, 1);
  }
  return dates;
};

var today = new Date(),
  last_year = new Date();

last_year.setMonth(last_year.getMonth() - 12);
last_year.setDate(last_year.getDate() + 1);
last_year.setHours(0,0,0,0);

var dates = getDates(last_year, today);

var d = new Date(2017, 10, 31);

var test = dates.map(Number).indexOf(+d);
console.log(test);

// works

dates = getDates(new Date(2017, 0, 4), new Date(2018, 12, 4));
d = new Date(2017, 10, 31);

test = dates.map(Number).indexOf(+d);
console.log(test);