如何在JavaScript数组中忽略时间按日期去重对象

1. 实现日期格式化函数 #

先写一个函数，把带时间的日期字符串（比如"August 15, 2022 at 9:00 AM"）转换成"Mon Aug 15 2022"格式：

function formatEventDate(dateStr) {
  // 拆分字符串提取纯日期部分
  const dateSegment = dateStr.split(' at ')[0];
  // 转成Date对象后调用toDateString得到目标格式
  return new Date(dateSegment).toDateString();
}

2. 处理数组并完成去重 #

遍历原始数组，统一格式化每个对象的eventDate，再利用Map实现去重（重复日期默认保留最后一个出现的对象，若要保留第一个可改用forEach遍历判断）：

// 你的原始数据数组
const originalData = [
  {
    formField7: "Test",
    amountDue: "Test",
    serviceType: "Course",
    staffMember: "Test",
    formField2: "Test",
    formResponse2: "-",
    formResponse7: "Test",
    formField6: "Test",
    formField10: "Test",
    paymentStatus: "Test",
    formField1: "Test",
    dateOfBooking: "Test",
    _id: "Test",
    _owner: "Test",
    _createdDate: "Test",
    serviceName: "Test",
    formField8: "Test",
    paymentMethod: "Test",
    groupSize: "1",
    formField4: "Test",
    formResponse1: "Test",
    formField5: "Test",
    _updatedDate: "Test",
    formResponse5: "Test",
    eventDate: "August 15, 2022 at 9:00 AM",
    formResponse8: "Test",
    couponName: "Test",
    formResponse0: "Test",
    formResponse11: "Test",
    clientEmail: "Test",
    formField9: "Test",
    attendanceStatus: "Test",
    sessionDuration: "Test",
    formField3: "Test",
    formResponse4: "-",
    clientAddress: "-",
    formResponse9: "Test",
    clientName: "Jane Doe",
    formField11: "Test",
    formResponse6: "Test",
    formField0: "Test",
    bookingStatus: "Test",
    clientPhoneNumber: "Test",
    amountPaid: "Test",
    formResponse10: "Test",
    formResponse3: "Test"
  },
  {
    formField7: "Test",
    amountDue: "Test",
    serviceType: "Course",
    staffMember: "Test",
    formField2: "Test",
    formResponse2: "-",
    formResponse7: "Test",
    formField6: "Test",
    formField10: "Test",
    paymentStatus: "Test",
    formField1: "Test",
    dateOfBooking: "Test",
    _id: "Test",
    _owner: "Test",
    _createdDate: "Test",
    serviceName: "Test",
    formField8: "Test",
    paymentMethod: "Test",
    groupSize: "1",
    formField4: "Test",
    formResponse1: "Test",
    formField5: "Test",
    _updatedDate: "Test",
    formResponse5: "Test",
    eventDate: "August 15, 2022 at 1:00 AM",
    formResponse8: "Test",
    couponName: "Test",
    formResponse0: "Test",
    formResponse11: "Test",
    clientEmail: "Test",
    formField9: "Test",
    attendanceStatus: "Test",
    sessionDuration: "Test",
    formField3: "Test",
    formResponse4: "-",
    clientAddress: "-",
    formResponse9: "Test",
    clientName: "Jane Doe",
    formField11: "Test",
    formResponse6: "Test",
    formField0: "Test",
    bookingStatus: "Test",
    clientPhoneNumber: "Test",
    amountPaid: "Test",
    formResponse10: "Test",
    formResponse3: "Test"
  }
];

// 格式化所有对象的eventDate字段
const formattedArray = originalData.map(item => ({
  ...item,
  eventDate: formatEventDate(item.eventDate)
}));

// 去重：利用Map的键唯一性，重复日期只保留最后一个
const uniqueArray = [...new Map(formattedArray.map(item => [item.eventDate, item])).values()];

// 若要保留第一个出现的重复项，可改用下面的写法
// const uniqueArray = [];
// const dateTracker = new Map();
// formattedArray.forEach(item => {
//   if (!dateTracker.has(item.eventDate)) {
//     dateTracker.set(item.eventDate, item);
//     uniqueArray.push(item);
//   }
// });

console.log(uniqueArray);

关键说明 #

• 日期格式化通过split(' at ')拆分字符串，精准提取不含时间的日期部分，再借助Date.toDateString()自动生成Mon Aug 15 2022格式的字符串
• 去重逻辑依赖Map的键唯一性，确保同一日期只保留一个对象

内容的提问来源于stack exchange，提问作者user9138698