TypeScript: What's going on here? function handleMainEvent( elem: HTMLFormElement, handler: FormSubmitHandler ) function handleMainEvent( elem: HTMLIFrameElement, handler: MessageHandler ) function handleMainEvent( elem: HTMLFormElement | HTMLIFrameElement, handler: FormSubmitHandler | MessageHandler ) {}

Question

What's going on here? function handleMainEvent( elem: HTMLFormElement, handler: FormSubmitHandler ) function handleMainEvent( elem: HTMLIFrameElement, handler: MessageHandler ) function handleMainEvent( elem: HTMLFormElement | HTMLIFrameElement, handler: FormSubmitHandler | MessageHandler ) {}

Kate W · Accepted Answer

This is an example of function overloading. Two function heads or overload signatures are written above the body of the function and serve as multiple entry points to a single implementation.

TypeScript

What's going on here? function handleMainEvent( elem: HTMLFormElement, handler: FormSubmitHandler ) function handleMainEvent( elem: HTMLIFrameElement, handler: MessageHandler ) function handleMainEvent( elem: HTMLFormElement | HTMLIFrameElement, handler: FormSubmitHandler | MessageHandler ) {}

This is an example of function overloading. Two function heads or overload signatures are written above the body of the function and serve as multiple entry points to a single implementation.

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