In this post, we will see how to resolve Property does not exists on type when using union with index signature Question: Let’s assume we have following interfaces: I create another interface which uses union of these interfaces: Now we ...

In this post, we will see how to resolve Typescript how to deal with union types and different attributes Question: I need to develop a function that accept 2 type of input. When I try to implement the function accepting ...

Question: I have this union type: And I would like a const [userInfos, setUserInfos] = useState<TUserInfos>{} to take just one of these types, but when I try to access userInfos only password is available. Can someone explain it to me? ...

Question: In the example below (playground link), I expect Foo<[0, 1]> and Bar<[0, 1]> both resolve to 0[] | 1[] because of the union distribution in conditional types. However, Foo<[0, 1]> is actually (0 | 1)[] and the compiler claims ...

Question: Pylance is advising to modify this line with two solution proposed. What would be the pros and cons of each one if there is any significant difference? Tuple expression not allowed in type annotation Use Tuple[T1, …, Tn] to ...

Question: In the above code, ts wont let me pass an object of Type to any function but processType1 since Type1 has attributes in common with the rest. How can I change my code to make this setup work? Answer: ...

Question: I am trying to define a TypeScript type that restricts values to the string versions of a set of numbers. Explanation below: Say I have a union numeric type like so: I would like to also define a companion ...

Question: I have a string literal union type that looks like this: This is only an example, since my union type is a list of more than 100 cases. What I need to have is a new type where I ...

Question: I would like to create a union type in TypeScript that can use an array as a discriminant, but have a specific type match if any element of the array meets some criteria, rather than all elements in the ...