Javascript中的月/日比较

问题描述：

I'm not an expert in JavaScript, but I've been tasked with migrating a very large website that was coded into PHP into a new CMS that does not allow server-side languages. I am therefore spending my days converting many PHP date-calcs to JavaScript.

Something very simple in PHP:

<?php 
if (date('md') < 816) {$award_year = date('Y');}
if (date('md') > 815) {$award_year = date('Y') + 1;}
/*echo "year ".$award_year;*/
?>

This allows the year an application is due to automatically change to next year after August 15.

I've been trying to recreate this effect with Javascript and here is what I have come up with:

var today = new Date();
var mm = today.getMonth()+1; //January is 0! 
var dd = today.getday();
if (mm < 10) {
    mm = '0'+mm
} 

currDate = mmdd;
var currDate = new Date(); 
var appDate = new Date("0816");

if (currDate < appDate){
var printDate = theDate.getFullYear();  
}

else if (currDate >= appDate){
var printDate = theDate.getFullYear()+1;      
}

I know that I am missing something, because the var currDate cannot just = mmdd and then be compared to another date. Can someone help me with the next step here ? I'm trying to actually learn JavaScript as I go rather than just blindly fix issues.

我不是JavaScript方面的专家，但我的任务是迁移一个编码过的大型网站将PHP导入到不允许使用服务器端语言的新CMS中。因此，我花了很多时间将许多PHP日期计算转换为JavaScript。 p>

PHP中非常简单： p>

 ＆lt;？php 
if（date（'md'）＆lt; 816）{$  award_year = date（'Y'）;} 
if（date（'md'）＆gt; 815）{$ award_year = date（'Y'）+ 1;} 
 / * echo“year”。$ award_year; *  / 
？＆gt; 
  code>  pre> 
 
 这允许应用程序在8月15日之后自动更改为明年。 p> 
 
  
 
 
  var today = new Date（）; 
var mm = today  .getMonth（）+ 1;  //一月是0！  
var dd = today.getday（）; 
if（mm＆lt; 10）{
 mm ='0'+ mm 
} 
 
currDate = mmdd; 
var currDate = new Date（）;  
var appDate = new Date（“0816”）; 
 
if（currDate＆lt; appDate）{
var printDate = theDate.getFullYear（）;  
} 
 
如果（currDate＆gt; = appDate）{
var printDate = theDate.getFullYear（）+ 1;  
} 
  code>  pre> 
 
 我知道我遗漏了一些东西，因为var currDate不能只是= mmdd，然后再与另一个日期进行比较。 有人可以帮助我下一步吗？ 我正在努力学习JavaScript，而不是盲目地修复问题。   p> 
  div>

答

This will look similar to your PHP code:

const date = new Date();
const day = date.getUTCDate();
const month = date.getMonth();
const md = month + "" + day;

if (md < 816) {
    var award_year = date.getFullYear();
}
else if (md > 815) {
    var award_year = date.getFullYear() + 1;
}

console.log(award_year);

</div>

答

Instead of combining strings and comparing two dates you could check the current day and month to determine which year to return.

For example,

function getAwardYear() {
  const today = new Date()
  const AUGUST = 7

  if (today.getMonth() >= AUGUST && today.getDate() > 15) {
    return today.getFullYear() + 1
  }

  return today.getFullYear()
}

// Today: 6th Jun 2018
getAwardYear() // 2018

// Today: 16th Aug 2018
getAwardYear() // 2019

答

I know there is plenty of things to improvise the below code... I am leaving it for you to improvise...

var today = new Date();
var mm = today.getMonth()+1; //January is 0! 
var dd = today.getDay();
if (mm < 10) {
    mm = '0'+mm
} 
var yyyy="2018"

var currDate = new Date(yyyy+"-"+mm+"-"+dd); 
var appDate = new Date("2018-01-16");

alert("appDate"+appDate);
alert("currDate"+currDate);

if (currDate < appDate){
var printDate = currDate.getFullYear();  
alert(printDate);
}
else if (currDate >= appDate){
var printDate = appDate.getFullYear()+1;    
alert(printDate);
    }

</div>

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