到下一个生日的剩余时间 javascript

Question

我正在尝试构建一个应用程序，用户可以 select 从日历中查看他们的生日，该应用程序以天、小时、分钟和秒为单位向用户显示他们的年龄和到下一个生日的剩余时间。 我正在使用反应日历和时刻。 我以某种方式获得了用户年龄，但我无法弄清楚如何获得剩余时间。 这是我的代码：

import React, { Component } from "react";
import Calendar from "react-calendar";
import moment from "moment";

export default class App extends Component {
  state = {
    date: new Date(),
    age: null,
    timeRemaining: {
      days: 0,
      hours: 0,
      minutes: 0,
      seconds: 0
    }
  };

  onChange = date => this.setState({ date });

  handleClick = () => {
    const birthday = moment(this.state.date).toDate();
    const now = new Date();
    const currentYear = now.getFullYear();
    const birthYear = birthday.getFullYear();
    let age = currentYear - birthYear;
    if (now < new Date(birthday.setFullYear(currentYear))) {
      age = age - 1;
    }

    this.setState({ age });
  };
  render() {
    console.log(this.state.date);
    console.log(this.state.age);

    return (
      <div>
        <Calendar
          onChange={this.onChange}
          value={this.state.date}
          onClickDay={this.handleClick}
        />

        <div>{this.state.age}</div>
      </div>
    );
  }
}

Answer 1

我不知道这是否是您要找的东西，但使用此代码我可以知道下一个生日还有多少个月和几天

const birthday = new Date(1992, 5, 22);
const currentDate = new Date(Date.now());

const birthdayMonth = birthday.getMonth();
const birthdayDay = birthday.getDate();

const nextBirthday = new Date(currentDate.getFullYear(), birthdayMonth, birthdayDay).getTime() < currentDate.getTime()
? new Date(currentDate.getFullYear() + 1, birthdayMonth, birthdayDay)
: new Date(currentDate.getFullYear(), birthdayMonth, birthdayDay);

let remainingTime = nextBirthday.getTime() - currentDate.getTime();

const remainingMonths = Math.floor((remainingTime / 1000) / (60 * 60 * 24 * 30));

remainingTime -= remainingMonths * (60 * 60 * 24 * 30 * 1000);

const remainingDays = Math.floor((remainingTime / 1000) / (60 * 60 * 24));

console.log(`Remaining ${remainingMonths} months and ${remainingDays} days until your birthday`);

Answer 2

由于您已经使用了 moment.js，因此您可以使用 moment.js 的比较方法。

// your specific birthday you want to compare
const myBirthday: Moment = moment("2020/01/03");
// date of today
const today: Moment = moment();
// if birthday is in past, add one year
if (today > myBirthday) {
  myBirthday.add(1, "year");
}
// calculate duration of difference between those two days
const duration: Duration = moment.duration(myBirthday.diff(today));
// output the duration as you wish
console.log(duration.get("month"));
console.log(duration.get("days"));