I know this is possibly doesn't exist, but can Typescript have a variable number of generics, each of their own type?
For example, instead of having something like function name(...args: any[]), I'd like to have a way that you could so something like
function name<T1, T2, T3...>(arg1: T1, arg2: T2, ...)
So if I were to do
name('string', 123, true)
I can then have the types of string, number, boolean as my generic types in the method.
Full-blown variadic kinds are not implemented in TypeScript, but luckily for your particular use case you can use tuple types in rest/spread expressions introduced in TS3.0:
function nameFunc<T extends any[]>(...args: T) {};
nameFunc('string', 123, true); // T inferred as *tuple* [string, number, boolean]
And you can access the individual member types via numeric lookup types:
// notice that the return type is T[1]
function secondItem<T extends any[]>(...args: T): T[1] {
return args[1];
}
const num = secondItem("string", 123, true); // number
Hope that helps; good luck!
It definitely is possible I guess. In below example, we should have type inference at every step while invoking the function getProperty.
function getProperty<T, K extends keyof T>(obj: T, key: K) {
return obj[key];
}
export interface User {
name: string;
}
type k = keyof User;
const user = { name: 'Krantisinh' };
getProperty<User, k>(user, 'name');
