ion-datetime - 从出生日期计算年龄

Question

I'm using ion-datetime picker to get the user's date of birth. I want to calculate the user's age based on their input. Not sure why the below isn't working...

html

<ion-datetime [(ngModel)]="userInfo.dateOfBirth"></ion-datetime>

typescript

public ageFromDOB(dateOfBirth) {
  const today = new Date();
  const birthdate = new Date(dateOfBirth);
  this.userInfo.age = today.getFullYear() - birthdate.getFullYear();
  const month = today.getMonth() - birthdate.getMonth();
  if ( month < 0 || (month === 0 && today.getDate() < birthdate.getDate())) {
    this.userInfo.age--;
  }
  return this.userInfo.age;
} 

Answer 1

The problem is probably the place where you're calling it from.

It's confusing with typescript projects as everything is async and it can run before something is populated and seem like its not working.

The ion-datetime has an ionChange event:

ionChange ion-datetime - Ionic Documentation

You should update the age when the datetime is changed:

<ion-datetime [(ngModel)]="userInfo.dateOfBirth" (ionChange)="ageFromDOB($event)"></ion-datetime>

You will still need to do a bit of homework I think:

public ageFromDOB(dateOfBirth) {
  console.log(dateOfBirth);
}

And then see what format the date is supplied in... seems like it's maybe an object but I'm just looking at github issues , which seems to say:

 updateMyDate($event) {
    const day: number = $event.detail.value.day.value;
    const month: number = $event.detail.value.month.value;
    const year: number = $event.detail.value.year.value;
 }