Here is a code snippet I found on the TypeScript Playground:
function foo(a: number, b: number) {}
const msg: any = {
params: [1,2],
};
// None of these works:
foo(...msg.params); // This should work but it doesn't
foo(...(msg.params as any));
foo((...msg.params) as any);
// Only this works:
(foo as any)(...msg.params);
The error message is:
A spread argument must either have a tuple type or be passed to a rest parameter.
msg/msg.params are already any. Why can't I use it for spread ... operator and pass as function argument? Isn't it the point of any? And why does casting the function to any works?
The forced compiled Javascript works:
"use strict";
function foo(a, b) {
console.log(a + b);
}
const msg = {
params: [1, 2],
};
foo(...msg.params); // Logs 3 correctly