Closed
Description
A contextual type assertion expression, <?>, is like a regular type assertion (e.g. <string>), but asserts to the contextual type of the expression.
About half of all type assertions can be rewritten this way with no loss of type safety.
Example:
declare function setDivText(div: HTMLDivElement): void;
// Error
setDivText(document.getElementById('myDiv'));
// OK, but a lot of typing
596F
setDivText(<HTMLDivElement>document.getElementById('myDiv'));
// OK and easy
setDivText(<?>document.getElementById('myDiv'));It is an error to use a contextual assertion when no contextual type exists:
<?>foo; // Error
var x: number = <?>foo; // OKThis should nearly eliminate assertions to <any> due to people not wanting to type out large type literals.