javascript - 节点获取映射错误 - 无法读取未定义的属性 'map'”

Question

当我尝试运行“ map ”部分时出现错误无法读取未定义的属性“ map ””

上面声明了 customers 常量，所以不确定。 undefined 是从哪里来的？ map 需要申报吗？

const AWS = require('aws-sdk'),
  ses = new AWS.SES(),
  fetch = require('node-fetch');

exports.handler = async (event) => {
  console.log(event.customer_id);

  const customers = await getCustomers();

  customers.map(async customer => await sendEmailToCustomer(customer));

  const customersEmailsPromises = customers.map(async customer => await sendEmailToCustomer(customer));

}

async function getCustomers() {
  try {
    const resp = await fetch('https://3objects.netlify.com/3objects.json');
    const json = await resp.json();

    return json;
  }
  catch(e) {
    throw e;
  }
}

const sendEmailToCustomer = (customer) => new Promise((resolve, reject) => {
  ses.sendEmail({
    Destination:
      { ToAddresses: [customer.email] },
    Message:
      {
        Body: { Text: { Data: `Your contact option is ${customer.customer_id}` } },
        Subject: { Data: "Your Contact Preference" }
      },
    Source: "sales@example.com"
  }, (error, result => {
    if (error) return reject(error);
    resolve(result);
    console.log(result);
  })
  );
})

Answer 1

getCustomers 不返回任何内容，这意味着 customers 被设置为 undefined。

试试这个:

async function getCustomers() {
  try {
    const resp = await fetch('https://3objects.netlify.com/3objects.json');
    const json = await resp.json();

    return json;
  }
  catch(e) {
    throw e;
  }
}

您还必须从作为参数传递给 .map 的函数返回一些内容

customers.map(async customer => {
    return await sendEmailToCustomer(customer);
});

或者只是:

customers.map(async customer => await sendEmailToCustomer(customer));

并且由于 .map 返回一个新数组(不会改变原始数组)，您必须存储返回值:

const customersEmailsPromises = customers.map(async customer => await sendEmailToCustomer(customer));