为什么我在Angular2中进行自定义验证不起作用

Question

Here are two angular2 custom validations that I wrote, the first one validateAge works, but the second one validateDob does not ... the difference is the validateAge uses the component that I am on and is a text based field, the second one needs to use a Date Entry field and find the difference between today's date and the birthdate to find the actual age and then measure it against the age field. but something is not right ... any ideas

function validateAge(control: FormControl): { [s: string]: boolean } {
  if (parseInt(control.value) <= 0) {
    return {invalidAge: true};
  }
}

function validateDob(control: FormControl): {[s:string]: boolean}{
  var today = new Date();
  var calcAge = today - control.value;
  if (calcAge != parseInt([{age}]) ){
    return {invalidDate: true}
  }
}

Answer 1

The issue you have here is that your control.value is not a Date object, but rather the string representation.

var today = new Date();

Difference in milliseconds between the current timestamp and the entered value

var diff = today - new Date(control.value);

divide by ms per year and take the floor

var calcAge = Math.floor(diff/ (1000*60*60*24*365)));

Now do whatever comparison you need against the appropriate value. You didn't show us what your age object is so I don't actually know what comparison you're looking for.

if (calcAge < someAgeThreshold) ){
    return {invalidDate: true}
} else {
    return null;
}

Also note that with custom validation the validator returns no error when you return null and anything with a value is considered to have an error.