Element implicitly has an 'any' type because expression of type '0' can't be used to index type 'RowDataPacket[] | RowDataPacket[][] | OkPacket | OkPacket[] | ResultSetHeader'. Property '0' does not exist on type 'RowDataPacket[] | RowDataPacket[][] | OkPacket | OkPacket[] | ResultSetHeader'. When trying to access any index of the result parameter in the callback

Hi there so I have this code

    static async getById(id: string): Promise<Business> {
        return new Promise((resolve, reject) => {
            connection.execute(
                "SELECT * FROM business WHERE ID = ?;",
                [id],
                (err, result) => {
                    if (err) reject(err);
                    const { id, name, email, password }: {id: string, name: string, email: string, password: string} = result[0]; //it complains here
                    resolve({
                        id,
                        name,
                        email,
                        password,
                    });
                }
            );
        });
    }

And I have typescript giving me this error:

Element implicitly has an 'any' type because expression of type '0' can't be used to index type 'RowDataPacket[] | RowDataPacket[][] | OkPacket | OkPacket[] | ResultSetHeader'.
  Property '0' does not exist on type 'RowDataPacket[] | RowDataPacket[][] | OkPacket | OkPacket[] | ResultSetHeader'.ts(7053)

And I’m really not sure what to be doing here because I can’t change return type of result

[astiob]

I’m using .execute<RowDataPacket[]>(...) for single-statement selects. Similarly, multi-statement selects would have .execute<RowDataPacket[][]>(...).

I don’t know whether the right type for inserts, updates, creates etc. is ResultSetHeader (which I’m getting in practice) or OkPacket | ResultSetHeader, though.

[sasial-dev]

+1, also an issue here got around it by typecasting, but I don’t know the library/mysql well so it’s not ideal.

			const [matches] = await db.Connection.query(
				"SELECT `Discord UID` FROM `Information` WHERE `Staff Code` = ? OR `Discord UID` = ? OR `Roblox UID` = ? OR `Email`= ?",
				[`${staffInfo.department}-${staffInfo.staffid}`, staffInfo.user.id, userId, staffInfo.email],
			);
			console.log((matches as RowDataPacket[])[0]);

this is with “mysql2/promise”