Overwrite function in TypeScript

问题

TypeScript: view on playground

alert = (function (origAlert) {
    return function (...messages: any[]) {
        origAlert(messages.join(" "))
    }
})(alert)

// Example
alert(1, 2)

I want to overwrite / redefine the function alert(message?: any) wich has already been declared in lib.d.ts before: declare function alert(message?: any): void;

But alert = function... throws "Invalid left-hand side of assignment expression."

The point is that, function alert(...messages: any[]) { /* ... */ } would work* does not even work aswell, but I need to use the original alert. And I'd dislike to define an extra const origAlert = alert before the function.

How can I do this?

---

Note that the compiled JavaScript in the Playground works as intended.

*on TypeScript Playground it works, but in Visual Studio it throws "Overload signatures must all be ambient or non-ambient"

回答1:

declare function alert(...messages: any[]): void;

window.alert = ((orig) => {
    return (...messages: any[]) => orig(messages.join(" "));
})(alert);

alert(1, 2)

来源：https://stackoverflow.com/questions/34238497/overwrite-function-in-typescript