How to change the output date format of input type="date" in angular 4?

You could change the date into dd/mm/yyyy format using DatePipe inside the checkDate() function. like below. And send that date into the server side.

first import the DatePipe into your component

import { DatePipe } from '@angular/common';

then use it like below

  checkDate() {
    const dateSendingToServer = new DatePipe('en-US').transform(this.Students.dob, 'dd/MM/yyyy')
    console.log(dateSendingToServer);
  }

working example you could be found here on STACKBLITZ DEMO.

Hope this will help to you!

You could try this -

import { DatePipe } from '@angular/common';

checkDate() {
    let formatedDate = new DatePipe().transform(this.Students.dob, 'dd/mm/yyyy')
    console.log(formatedDate); 
  }