Otherwise browsers might treat some attributes (e.g. "title") specially.
To see it in action, go to gov-personal-details component example, Angular Markup tab, and hover the mouse over the rendered component. On Chrome, a tooltip appears with "$ctrl.title" in it.
To avoid such surprises, it would probably be best practice to add "data-" prefix when using any custom attribute (even on custom elements).
Otherwise browsers might treat some attributes (e.g. "title") specially.
To see it in action, go to gov-personal-details component example, Angular Markup tab, and hover the mouse over the rendered component. On Chrome, a tooltip appears with "$ctrl.title" in it.
To avoid such surprises, it would probably be best practice to add "data-" prefix when using any custom attribute (even on custom elements).