Typescript promise generic type
The generic type of the Promise should correspond to the non-error return-type of the function. The error is implicitly of type any and is not specified in the Promise generic type.
So for example:
function test(arg: string): Promise<number> {
return new Promise<number>((resolve, reject) => {
if (arg === "a") {
resolve(1);
} else {
reject("1");
}
});
}