JavaScript 异步/等待 : await is a reserved word

Question

这个问题已经有答案了:

Use async await with Array.map (9 个回答)

已关闭 5 年前。

这是一个检查 mongoose 是否有重复记录的函数。在这种情况下name和email是唯一字段，因此如果数据库中存在具有相同名称或电子邮件的记录，则无法插入新记录:

const checkIfDatabaseHasUsersWithSameNameAndEmail = async () => {

    uniques = ['name', 'email'];
    uniques.map((field) => {
        let query = {};
        query[field] = data[field];
        query.deleted = false;
        let result = await model.findOne(query); <== ERROR: await is a reserved word

        if (result) {
            errors.push({
                field: field,
                message: 'A record already exists in database for ' + field + '=' + data[field]
            });
        }
    });

    if (errors.length > 0)
        return errors;
}

schema.statics.create = function (data) {

    let errors = await checkIfDatabaseHasUsersWithSameNameAndEmail(); <== ERROR: await is a reserved word

    if (errors)
        throw new Error(errorMessages);

    let company = new this(data);
    return company.save();
}

运行时，我在代码中发现以下错误:await is a reserved word

这是我第一次使用 async/await，所以可能我的做法是错误的。我的目标是按顺序运行唯一的测试(findOne)，如果一切顺利，则保存新的寄存器。

Answer 1

错误是因为您试图等待某些内容，但尚未声明函数异步。我没有用 Mongoose 测试这个，但它看起来像这样。

async function checkIfDatabaseHasUsersWithSameNameAndEmail(data) {
  const uniques = ['name', 'email'];
  return Promise.all(uniques.map(async (field) => {
    const query = {};
    query[field] = data[field];
    query.deleted = false;
    return model.findOne(query);
  }));
}

schema.statics.create = async function create(data) {
  try {
    const results = await checkIfDatabaseHasUsersWithSameNameAndEmail(data);
    results.forEach((result) => {
      console.log(`Here's the issue: ${JSON.stringify(result)}`);
      throw new Error('Do something about it.');
    });

    const company = new this(data);
    return company.save();
  } catch (error) {
    throw error;
  }
};