显示本月的第二个星期五-Javascript

Question

我正在制作一个网页，显示食品储藏室的下一个日期。它发生在这个月的第二个星期五。我从这个问题中获得了当前的代码，我想我可以修改它来满足我的需求。然而，我希望它以"April，10th"的格式显示，而不是"04/10/2020"。我对Javascript有非常基本的理解，所以如果你像我五岁一样解释它会很有帮助。

此外，如果第二个星期五是今天，如果它能说今天就太好了。

谢谢！

Date.prototype.nextsecondFriday = function (){
// Load the month.
var target = new Date(this.getFullYear(), this.getMonth(), 1, 0, 0, 0);
var today = new Date();
// Check to see if the 1st is on a Friday.
var isFriday = (target.getDay() == 1);
// Jump ahead two weeks from the 1st, and move back the appropriate number of days to reach the preceding Friday.
// i.e. If the 1st is a Thursday, we would move back three days.
var targetDate = 12 - (target.getDay() - 1);
// Quick adjustment if the 1st is a Friday.
if (isFriday) targetDate -= 4;
// Move to the second Friday in the month.   
target.setDate(targetDate);
// Second Friday is before today's date, so find the second Friday next month.
if (today > target) {
//return "<em>" + target.toLocaleDateString() + " is in the past...</em>";
target.setMonth(target.getMonth() + 1);
return target.nextsecondFriday();
}
// Format and return string date of second Friday.
return target.toLocaleDateString();
}

var secondFridayDateString = new Date().nextsecondFriday();
document.getElementById("dynamicdate").innerHTML = secondFridayDateString;

<p>Our next food pantry is <span id="dynamicdate">Second Friday</span>.</p>

Answer 1

下面的代码为任何Date((找到第二个星期五

Date.prototype.nextsecondFriday = function() {
// get second firday for given month and year
const secondFriday = (year, month) => {
// first day of the month
let date = new Date(year, month, 1);
let dayDifference = 5 - date.getDay();
// get second friday of the month
if (dayDifference < 0) {
date.setDate(date.getDate() + (14 + (-1 * dayDifference)));
} else if (dayDifference >= 0) {
date.setDate(date.getDate() + 7 + dayDifference);
}
return date;
};
// format date to "April 10th"
const formatDate = (date) => {
const months = ["January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"];
const month = months[date.getMonth()];
const day = date.getDate();
let suffix = 'th';
const j = day % 10,
k = day % 100;
if (j == 1 && k != 11) {
suffix = "st";
} else if (j == 2 && k != 12) {
suffix = "nd";
} else if (j == 3 && k != 13) {
suffix = "rd";
}
return `${month} ${day}${suffix}`;
};
let date = this;
let closestSecondSaturday;
do {
let secondFridayOfThisMonth = secondFriday(date.getFullYear(), date.getMonth());
if (secondFridayOfThisMonth.getDate() === date.getDate()) {
closestSecondSaturday = "Today";
} else if (secondFridayOfThisMonth.getDate() >= date.getDate()) {
closestSecondSaturday = formatDate(secondFridayOfThisMonth);
} else {
// if current date has crossed the second friday, move to the next month
date.setMonth(date.getMonth() + 1);
}
} while (!closestSecondSaturday)
return closestSecondSaturday;
};
// sample call
document.write(new Date().nextsecondFriday());

Answer 2

尝试新的Intl.DateTimeFormat('en-US'，选项(.format(目标(

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DateTimeFormat

Date.prototype.nextsecondFriday = function (){
// Load the month.
var target = new Date(this.getFullYear(), this.getMonth(), 1, 0, 0, 0);
var today = new Date();
// Check to see if the 1st is on a Friday.
var isFriday = (target.getDay() == 1);
// Jump ahead two weeks from the 1st, and move back the appropriate number of days to reach the preceding Friday.
// i.e. If the 1st is a Thursday, we would move back three days.
var targetDate = 12 - (target.getDay() - 1);
// Quick adjustment if the 1st is a Friday.
if (isFriday) targetDate -= 4;
// Move to the second Friday in the month.   
target.setDate(targetDate);
// Second Friday is before today's date, so find the second Friday next month.
if (today > target) {
//return "<em>" + target.toLocaleDateString() + " is in the past...</em>";
target.setMonth(target.getMonth() + 1);
return target.nextsecondFriday();
}
let options = { year: 'numeric', month: 'long', day: 'numeric' };
// Format and return string date of second Friday.
return new Intl.DateTimeFormat('en-US', options).format(target);
}

var secondFridayDateString = new Date().nextsecondFriday();
document.getElementById("dynamicdate").innerHTML = secondFridayDateString;

<p>Our next food pantry is <span id="dynamicdate">Second Friday</span>.</p>

Answer 3

我会修改nextsecondFriday函数以返回日期对象，而不是格式化的字符串(只需放弃toLocaleDateString()调用(。

然后编写另一个函数formatDate，它接收一个日期并返回一个格式化的字符串。

然后调用nextsecondFriday获取日期并使用formatDate对其进行格式化。

如果您需要特定的格式(冒号和"th"等(，格式化的代码(formatDate函数(可能类似于：

const event = new Date(Date.UTC(2012, 11, 20, 3, 0, 0));
const monthOptions = { month: 'long' };
const dayOptions = { day: 'numeric' };
const formattedDate = event.toLocaleDateString('en-US', monthOptions) + ', ' + event.toLocaleDateString('en-US', dayOptions));
// then check event.getDay() and append 'st', 'nd', 'rd' or 'th' to formattedDate as needed

但是，如果您可以使用另一种格式，那么只需调用一次toLocaleDateString就足够了——有关详细信息，请参阅MDN上的LocaleDateString文档。

Answer 4

请参阅toDateString你只需要更改这个报表

return target.toDateString();

Answer 5

options = { weekday: 'long', year: 'numeric', month: 'long', day: 'numeric' };
secondFridayDateString.toLocaleDateString("en-us", options)

你需要设置格式，检查一下。

你可以在控制台上玩这个，只需做：

let date = new Date()
options = { weekday: 'long', year: 'numeric', month: 'long', day: 'numeric' };
date.toLocaleDateString("en-us", options) //set your locale as you want i.e. es-ar or any locale