Description

In order to enhance the safety and reliability of our TypeScript codebase, I propose that we add the "noUncheckedIndexedAccess": true option to our tsconfig.json. This strict check will help prevent potential runtime errors caused by undefined index access in arrays or objects.

Motivation

Recently, a bug related to an undefined index access was encountered when @ziyebuxiu attempted to access an element in a singleton array using an index. Here is the scenario that illustrates the issue:

• We have an array questionId that is expected to be a singleton array.
• A member tried accessing the second element with questionId[1], which is undefined.
• This led to a BadRequestException: Validation failed (numeric string is expected) error, because the API expected a numeric string, but received undefined due to the out-of-bounds access.

Suggested Solution

To avoid such errors and enforce better type checking, we can use the "noUncheckedIndexedAccess": true option, which will make sure that every property access includes undefined in the type if there's no explicit index signature.

I believe this change will encourage our developers to write more robust code and perform the necessary checks before accessing array indexes, ultimately leading to a more stable application.