Slightly Improved phone validator.

[mmsaffari]

The RegExp used in the original code was too loose for a valid Phone number and on the other hand, phone numbers have somewhat different patterns around the world. According to Mozilla one should be able to use the pattern attribute on an <input type="tel" /> element to indicate the RegExp to be used to validate the phone number.

This PR takes the pattern attribute into account.

[mmsaffari]

I should have checked to see if the element has a pattern attribute.
But why is it trying to get the pattern attribute from a select?

Property 'pattern' does not exist on type 'HTMLSelectElement'.

[haacked]

Maybe it should be:

Suggested change

	let r = element.pattern ? new RegExp(element.pattern) : /^\+?[0-9\-\s]+$/;
	let pattern = element.getAttribute('pattern');
	let r = pattern ? new RegExp(pattern) : /^\+?[0-9\-\s]+$/;

[dahlbyk]

But why is it trying to get the pattern attribute from a select?

Property 'pattern' does not exist on type 'HTMLSelectElement'.

Because element: ValidatableElement and only HTMLInputElement has pattern:

aspnet-client-validation/src/index.ts

Line 32 in 061c242

export type ValidatableElement = HTMLInputElement | HTMLSelectElement | HTMLTextAreaElement;

The getAttribute solution works, but you can make TS happy with either:

Suggested change

	let r = element.pattern ? new RegExp(element.pattern) : /^\+?[0-9\-\s]+$/;
	let r = 'pattern' in element && element.pattern ? new RegExp(element.pattern) : /^\+?[0-9\-\s]+$/;

or

Suggested change

	let r = element.pattern ? new RegExp(element.pattern) : /^\+?[0-9\-\s]+$/;
	let r = element instanceof HTMLInputElement && element.pattern ? new RegExp(element.pattern) : /^\+?[0-9\-\s]+$/;

While we're in the area, it could be handy to assign/use the default pattern as something like static phonePattern to allow overriding everywhere by assigning MvcValidationProviders.phonePattern.

[Grizzlly]

@mmsaffari Hello! Would you be able to update this?