Connection.query() return type

[taeh98]

Hello, I hope this finds you well.

Please could you add a meaningful return type to Connection.query() (specifically, in the TypeScript typing of it)? At the moment, it returns a Promise<any>. Using an any value means that the value could be of any type, and defeats the purpose of using typed TypeScript over untyped JavaScript to begin with. As far as I can tell, it will either return an OkPacket or throw an error. Please could you, therefore, change the return type to something like Promise<OkPacket>? I don't think an OkPacket TypeScript class exists right now but, as far as I can tell, it wouldn't be too complex to create.

Thank you for your time and consideration.

[rusher]

It would be nice to have, but not as simple than that.
Problem is that result type depends on options.

For update/insert there is already an UpsertResult type defined, return would be Promise

await connection.query('CREATE TABLE animals (' +
                       'id MEDIUMINT NOT NULL AUTO_INCREMENT,' +
                       'name VARCHAR(30) NOT NULL,' +
                       'PRIMARY KEY (id))');
let res = await connection.query('INSERT INTO animals(name) value (?)', ['sea lions']);
console.log(res);
//log : { affectedRows: 1, insertId: 1, warningStatus: 0 }
res = await connection.query('select * from animals');
console.log(res); 
// [ 
//    { id: 1, name: 'sea lions' }, 
//    { id: 2, name: 'bird' }, 
//    meta: [ ... ]
// ]

That's for the default option value. but let me show the problem with only 2 options rowsAsArray and nestTables:

res = await connection.query({ rowsAsArray: true, sql: 'select * from animals' });
console.log(res); 
// [ 
//    [ 1, 'sea lions' ], 
//    [ 2, 'bird' ],
//    meta: [...]
// ]

res = await connection.query({
  nestTables: true, 
  sql:'select a.name, a.id, b.name from animals a, animals b where b.id=1'
});
console.log(res); 
//[ 
//  { 
//     a: { name: 'sea lions', id: 1 }, 
//     b: { name: 'sea lions' } 
//  },
//  { 
//     a: { name: 'bird', id: 2 }, 
//     b: { name: 'sea lions' } 
//  },
//  meta: [...]
//]

another options multipleStatements make INSERT/UPDATE command not result in Promise, permitting multiple result.

The only choice would be to remove rowsAsArray, nestTables and multipleStatements from typescript.
The result would then be
query(sql: string): Promise<UpsertResult> | Promise<[]>;

That would not be so interesting.

Maybe another notation like in JDBC that have 2 differents commands executeUpdate and executeQuery that do the same thing, one expecting to do insert/update while the second return a resultset, to return precise results:

executeUpdate(sql: string): Promise<UpsertResult>;
executeQuery(sql: string): Promise<[]>;

That might have more interest this way

[whitebyte]

Since a programmer knows what kind of query he calls this could be passed as a generic param, something like

const res: RowArrayResult  = await connection.query<RowArrayResult>({ rowsAsArray: true, sql: 'select * from animals' });
const res: RowObjectResult  = await connection.query<RowObjectResult>({ sql: 'select * from animals' });

[rusher]

definitively a better approch. I've created https://jira.mariadb.org/browse/CONJS-184 for this.

[rusher]

Do i miss something or JSON type is still now permitted in Typescript ?
default return type for a result-set would be Promise<Json[]>.
Since i don't found a real json type, the only solution would be Promise<any[]> that would not help at all.

[whitebyte]

There is no JSON type in TS. Maybe Promise<Record<string, any>> or something like that would work?