node.js - 如何在 foreach 循环中使用多个异步等待调用将返回值推送到数组中

Question

我想在 forEach 循环中进行多个异步等待函数调用，并将返回值推送到数组中。但它返回一个 promise 。如何将实际返回值存储在数组中？感谢您的帮助。

let table1Assignments = [];
        await groupingTable1Id.forEach(table1Id => {(
             table1Assignments.push(assignmentsDAO.getAssignmentsOfTable(table1Id, date, time)))
        });

getAssignmentsOfTable 看起来像这样:

 async getAssignmentsOfTable(tableId, date = null) {
   let stmt =
      `SELECT * 
       FROM assignment a
       WHERE a.dining_table_id = $1` + (date?' AND a.date = $2':'');
    const params = date?[tableId, date]:[tableId];

    const result = await this.db.query(stmt, params);

    return result.rows.map(row => {
        return new Assignment(
          row.id,
          row.dining_table_id,
          row.guest_group_id,
          row.date,
          row.time
        );
    });
}

Answer 1

我会遵循这种模式:

Promise.all([
  groupingTable1Id.map(table1Id => assignmentsDAO.getAssignmentsOfTable(table1Id, date, time))
]).then((table1Assignments) => {
  table1Assignments.forEach(assignment) { process(assignment) });
});

查看有关 JavaScript (ES6) 的文档 Promise.all here ...