Function powerSyncUpdateThenInsert

src/persisters/persister-powersync/index.ts:75–126

(
  executeCommand: DatabaseExecuteCommand,
  tableName: string,
  rowIdColumnName: string,
  changingColumnNames: string[],
  rows: {[id: string]: any[]},
)

// PATCHes. Update first so existing rows avoid replacement writes in the upload
// queue, then insert only when RETURNING shows that no row existed.
const powerSyncUpdateThenInsert: Upsert = async (
  executeCommand: DatabaseExecuteCommand,
  tableName: string,
  rowIdColumnName: string,
  changingColumnNames: string[],
  rows: {[id: string]: any[]},
) => {
  const assignments = arrayJoin(
    arrayMap(
      changingColumnNames,
      (columnName, index) => escapeId(columnName) + '=$' + (index + 1),
    ),
    COMMA,
  );
  for (const [id, row] of objToArray(rows, (row, id): [string, any[]] => [
    id,
    row,
  ])) {
    const rowParams = arrayMap(row, (value) => value ?? null);
    if (
      arrayIsEmpty(
        await executeCommand(
          UPDATE +
            escapeId(tableName) +
            ' SET' +
            assignments +
            ' ' +
            WHERE +
            escapeId(rowIdColumnName) +
            '=$' +
            (row.length + 1) +
            ' RETURNING' +
            escapeId(rowIdColumnName),
          [...rowParams, id],
        ),
      )
    ) {
      const offset = [1];
      await executeCommand(
        INSERT +
          ' INTO' +
          escapeId(tableName) +
          '(' +
          escapeColumnNames(rowIdColumnName, ...changingColumnNames) +
          ')VALUES(' +
          getPlaceholders([id, ...row], offset) +
          ')',
        [id, ...rowParams],
      );
    }
  }
};