You’re right that this is really easy to mess up, especially when defining an ar...

throwaway284534 on Oct 12, 2021 | parent | context | favorite | on: Tricks I wish I knew when I learned TypeScript

You’re right that this is really easy to mess up, especially when defining an array index e.g.

    const todos: string[] = [“walk dog”];
    todos[123].toUpperCase() // error!

IMO non constant (as defined by TypeScript) arrays should’ve been automatically assigned a union type with `undefined`, which can also be a fix for Records too:

    type Tips = Record<string, TipObject | undefined>

jakelazaroff on Oct 12, 2021 [–]

You’re looking for the noUncheckedIndexAccess compiler option: https://www.typescriptlang.org/tsconfig#noUncheckedIndexedAc...