Provide an option to disable JSON parsing

In both binary_parser.js and text_parser.js we’re parsing the JSON string to a native object:

case Types.JSON:
  // Since for JSON columns mysql always returns charset 63 (BINARY),
  // we have to handle it according to JSON specs and use "utf8",
  // see https://github.com/sidorares/node-mysql2/issues/409
  return 'JSON.parse(packet.readLengthCodedString("utf8"))';

Similarly to the configuration option dateStrings, it would be nice to provide something like jsonStrings which would avoid this and just return the utf8 string.

[OrkhanAlikhanov]

I need to disable this as well. It’s for perf reasons. Also mysql package has this disabled (probably not implemented at all). Switching to mysql2 was not smooth for me because of this feature. I’d be happy to see option to disable this

[bunchjesse]

Yeah, here is what I settled on to get unblocked (in case anyone else finds it helpful):

async function performWithTypeCastsDisabled(ctx: AppContext, fn: () => Promise<any>) {
  const oldTypeCast = ctx.db.client.connectionSettings.typeCast;
  const oldDateStrings = ctx.db.client.connectionSettings.dateStrings;
  // Provide a custom typeCast functionm that disables JSON parsing
  // See https://github.com/sidorares/node-mysql2/issues/1072
  ctx.db.client.connectionSettings.typeCast = function (field: any, next: any, packet: any) {
    if (field.type === "JSON") {
      return field.string();
    } else {
      return next();
    }
  }
  // Disable parsing to date object because this causes the format
  // to change and it isn't directly re-importable after.
  ctx.db.client.connectionSettings.dateStrings = true;
  await ctx.db.destroy();
  await ctx.db.initialize();
  await fn();
  ctx.db.client.connectionSettings.typeCast = oldTypeCast;
  ctx.db.client.connectionSettings.dateStrings = oldDateStrings;
  await ctx.db.destroy();
  return ctx.db.initialize();
}