How to process req.body received as an array-CodePudding

I have a myPlaylistSongs table, and there are Playlist_ID and Song_ID columns in it. Each row can have only one value, and the table format is as follows.

=====================
Playlist_ID | Song_ID
---------------------
1           | 5
1           | 3
1           | 8
=====================

Customers can create a playlist and add multiple songs to it, or delete multiple songs from it.

Playlist_ID is received as Path params, and Song_ID is received as req.body.

If Song_ID is received as an array here, how can I add the Song_ID corresponding to the Playlist_ID received as Path params at once?

The query is as below. DAO.js

const postSongs = async(playlistId, songId) => {
  const playlist = await myDataSource.query(
    `INSERT INTO myPlaylistSongs(playlist_id, song_id)
      VALUES(?, ?)`,
    [playlistId, songId],
  );
  return playlist;
};

I need help.

CodePudding user response：

Try something like this

const postSongs = async(playlistId, songId) => {
  const playlist = await myDataSource.query(
    `INSERT INTO myPlaylistSongs(playlist_id, song_id) 
     VALUES ${songId.map((sID) => "(" sID "," playlist_id ")").join(",")},
  );
  return playlist;
};

CodePudding user response：

You should be able to build a single query by specifying an array of (?, ?) and for the values to be inserted:

const postSongs = async (playlistId, songId) => {
  if (songId.length  === 0) return []; // Empty array
  let valuesString = '(?, ?),'.repeat(songId.length);
  // Remove last comma
  valuesString = valuesString.substring(0, values.length - 1);
  const valuesArr = [];
  for (const song of songId) {
      valuesArr.push(playlistId);
      valuesArr.push(song);
  }
  const playlist = await myDataSource.query(
    `INSERT INTO myPlaylistSongs(playlist_id, song_id)
      VALUES ${values}`,
    valuesArr
  );
  return playlist;
};