I need this type
type Sample = [a: string, b: number]
to be converted to
type Sample2 = { a:string, b:number}
I need this to pass arguments of a function in a paramenter, in form of an object
function example(otherFunctionParameters: Parameters<typeof otherFunction>){}
I don't want to pass an array in the parameter.
How can I achieve this ?
Because you can't manipulate tuple labels in the type system, the best you can do is manually supply a tuple of property keys, one for every parameter in the original function.
By adapting some utilities from this answer by jcalz, here's a generic utility that will give you a mapped object for the parameters in a function: You supply the function type and a tuple of labels for each parameter:
type ZipTuples<Keys extends readonly any[], Values extends readonly any[]> = {
[K in keyof Keys]: [Keys[K], K extends keyof Values ? Values[K] : never];
};
type ZipTuplesAsObject<
Keys extends readonly PropertyKey[],
Values extends readonly any[],
> = { [T in ZipTuples<Keys, Values>[number] as T[0]]: T[1] };
type ParamsAsObject<
Fn extends (...params: readonly any[]) => any,
Keys extends readonly PropertyKey[],
> = ZipTuplesAsObject<Keys, Parameters<Fn>>;
// Use
declare function otherFunction (
irrelevantLabel: string,
alsoNotUsed: number,
onlyTheTypesMatter: boolean,
): void;
function example (objectParam: ParamsAsObject<typeof otherFunction, ['a', 'b', 'c']>) {
// objectParam; // { a: string; b: number; c: boolean; }
const {a, b, c} = objectParam;
a; // string
b; // number
c; // boolean
}
It has to be passed in as an array unfortunately because an object is a different type than an array.
type Sample = [a: string, b: number]
type Sample2 = { a:string, b:number}
function example(otherFunctionParameters: Sample){}
function example2(otherFunctionParameters: Sample2){}
example(['b', 3])
example2({a: 'b', b: 2})
I recommend changing the signature type of the calling function. If this is not possible, an array should work just fine.