Question

我正在尝试将一些代码从回调更改为promise，将.promise添加到aws调用中。

...
<select [(ngModel)]="district_id" name="districts" class="rounded-inputs20 select-select col-md-3">
        <option *ngFor="let district of districts" [ngValue]="district.id">{{district.name}}</option>
</select>
...

我认为这是正确的，但测试有问题。我收到错误'TypeError：docClient.scan（...）。promise不是函数'我认为它与模拟的编写方式有关。

const AWS = require("aws-sdk")

const docClient = new AWS.DynamoDB.DocumentClient({
  apiVersion: "2012-08-10",
  region: process.env.AWS_REGION
})

class Stuff {
   getRawItems() {
     let params = {
        TableName : "TableName"
     }

     return docClient.scan(params).promise()
       .then(function(data) {
          return data.Items
       })
       .catch(function(err) {
         console.warn("Error with Dynamo request", err)
         throw err
       })
   }
}

Answer 1

模拟是问题，这是以下示例代码：

const fakePromise = {
   promise : jest.fn()
}
const fakeDynamo = { scan: () => {
   return fakePromise
}}

const realAWS = require("aws-sdk")
realAWS.DynamoDB.DocumentClient = jest.fn( () => fakeDynamo )
const Stuff = require("../src/stuff").Stuff

test("Test that the scan is performed and the data comes back", done => {
  fakePromise.promise.mockImplementation(() => Promise.resolve({Items:[1,2,3]}))
  const stuff = new Stuff()
  const defaultItems = stuff.getRawItems(lat, lon)
  defaultItems.then ( (data) => {
     expect(fakePromise.promise).toHaveBeenCalledTimes(1)
     expect(data.length).toEqual(3)
     done()
  })
})

Answer 2

我遇到了这个问题并找到了最简单的解决方案，让模拟器发送一个被视为承诺的回调。

var socket = io.connect('http://localhost:3000');

Answer 3

也许读过Promises，我想

</style>
<script type="text/javascript" src="http://maps.google.com/maps/api/js?sensor=false"></script>
<script src="jquery.js"></script>
<script type="text/javascript">
(function() {
window.onload = function() {
var map;
var locations = [
<?php
     //konfgurasi koneksi database 
      mysql_connect('localhost','root','');
      mysql_select_db('candralab-map');

            $sql_lokasi="select idlokasi,lat,lon
            from lokasi  ";
            $result=mysql_query($sql_lokasi);
            // ambil nama,lat dan lon dari table lokasi
            while($data=mysql_fetch_object($result)){
                 ?>
         ['<?=$data->idlokasi;?>', <?=$data->lat;?>, <?=$data->lon;?>],
   <?
            }
?>
];

var options = {
  zoom: 12, //level zoom
  //posisi tengah peta
  center: new google.maps.LatLng(-7.8008, 110.380643),
  mapTypeId: google.maps.MapTypeId.ROADMAP
};

var map = new google.maps.Map(document.getElementById('peta'), options);
  var infowindow = new google.maps.InfoWindow();

var marker, i;
for (i = 0; i < locations.length; i++) {  
  marker = new google.maps.Marker({
    position: new google.maps.LatLng(locations[i][1], locations[i][2]),
    map: map,
     icon: 'icon.png'
  });       
        google.maps.event.addListener(marker, 'click', (function(marker, i) {
        return function() { 
            var id= locations[i][0];
            $.ajax({
                url : "get_info.php",
                data : "id=" +id ,
                success : function(data) {
                        $("#info").html(data);
                }
            });     
        }
    })(marker, i));
}
};
 })();</script>

应该是：

 return docClient.scan(params).promise()
   .then(function(data) {
      return data.Items
   })
   .catch(function(err) {
     console.warn("Error with Dynamo request", err)
     throw err
   })

解析器告诉你：return docClient.scan(params) .then(function(data) { return data.Items }) .catch(function(err) { console.warn("Error with Dynamo request", err) throw err })函数的结果没有promise函数。

错误嘲笑aws承诺

3 个答案: