The classification of a dictionary and a list in Typescript

Can you spot the difference between the two codes below for defining a type of props?

I realized that the first one didn't throw a type error, but I can't figure out why my initial second code was incorrect. To me, it seems like it should work perfectly fine.


type Props = {
  reason: {
    id: number;
    title: string;
    description: string;
    reference?: 
      {
        title: string;
        link: string;
      }[];
  };
};

and


type Props = {
  reason: {
    id: number;
    title: string;
    description: string;
    reference?: [
      {
        title: string;
        link: string;
      }
    ];
  };
};

Answer №1

The error occurred due to the data type assigned to the reference property. In the initial Props, the reference is structured as an array of:

{
   title: string;
   link: string;
}

However, in the subsequent Props, a tuple was defined instead of an array. This means that it only consists of 1 element.

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