如何用点将日期19990813（YYYY-MM-DD）格式化为13.08.1999（DD-MM-YYYY）？

Question

I have problem to convert the date 19990813 of type string given by the backend to 13.08.1999 with the dots. I am not able to do so..

Using Angulars in-build date-format-function I got always the wrong date.

How can I achieve my goal?

I am thankful for any advice.

Kind regards

Anna Marie

Answer 1

You can install npm i moment and use like this

datestring = '19990813';
  constructor(){
     let date = moment(this.datestring, 'YYYYMMDD');
     let datedot = date.format('DD.MM.YYYY');
     alert(datedot);
  }

Demo https://stackblitz.com/edit/moment-js-format

Answer 2

You can use String replace() for this.

 let date = `19990813` let regex = /^(\\d{4})(\\d{2})(\\d{2})$/ let newDate = date.replace(regex, "$3.$2.$1") console.log(newDate) 

Answer 3

If you need to do this string transformation in a component's template, the best choice (for performance reasons) is to use a pipe operator.

Use the solution proposed by xyz for the string transformation itself.

import {Pipe, PipeTransform} from '@angular/core';

@Pipe({
    name: 'myDateFormat'
})
export class MyDateFormatPipe implements PipeTransform {

    transform(value: string, args?: any): any {
        if (!value) {
            return value;
        } else {
            // process the 'value' param and return its result according to xyz's solution
        }
    }
}

then in your template, use it like this:

inputDate | myDateFormat

where inputDate is '19990813'.

And don't forget to import this class to the angular module that will use it.