将UNIX时间戳转换为字符串

Question

I'm using Polymer and I have a date as a UNIX timestamp (eg 1487016105201) that I want to format as mm/dd/yyyy - hh/mm .

I resolved the problem... see below:

<vaadin-grid-column>
  <template class="header">BINTS01 - last scan</template>
  <!--<template>[[item.BINTS01]]</template>  this works-->
  <template>[[_formatEpochDate(item.BINTS01)]]</template>
</vaadin-grid-column>

The <script> section is:

<script>
Polymer({
  is: 'my-view8',
  properties:{
      eTS : String,
      },
  _formatEpochDate: function(eTS){
      // return eTS
      var d = new Date(eTS);
      var n = d.getUTCDay();
      return d.toDateString()
       },        
});

Answer 1

There are at least two reasons why Date(eTS).toUTC isn't working.

1. Calling Date as a function (ie Date(eTS) without new ) returns a string, not a Date object. You want new Date(eTS) .
2. Neither Strings nor Date objects have a property named toUTC (nor do they have a method named toUTC , so toUTC() won't work either). Maybe you meant toUTCString() ?

With the above facts in mind, you could change your code to this:

 function _formatEpochDate(eTS) { return new Date(eTS).toUTCString(); } const dateString = _formatEpochDate(1487016105201); console.log(dateString); 

 .as-console-wrapper{min-height:100%;} 

...but that doesn't give you your desired format. Per MDN :

The value returned by toUTCString() is a human readable string in the UTC time zone. The format of the return value may vary according to the platform. The most common return value is a RFC-1123 formatted date stamp, which is a slightly updated version of RFC-822 date stamps.

There are a variety of ways you could solve this, including writing your own date formatter. Another option is to use a library like strftime , as below:

 function _formatEpochDate(eTS) { return strftime('%D - %H:%M', new Date(eTS)); } const dateString = _formatEpochDate(1487016105201); console.log(dateString); 

 .as-console-wrapper{min-height:100%;} 

 <script src="https://unpkg.com/strftime@0.10.0/strftime-min.js"></script>