未捕获的ReferenceError：infowindow未定义#googleMaps API

Question

我正在尝试将Google Maps API集成到我的网页中。我使用从JSON中提取位置的代码并将位置保存在数组中，然后返回每个位置的位置数据。一切顺利，但我在点击地图上的标记时无法激活infowindow功能。这是单击时出现的错误：

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var map;    // declares a global map variable


/*
Start here! initializeMap() is called when page is loaded.
*/
function initializeMap() {

  var locations;

  var mapOptions = {
    disableDefaultUI: true
  };

  /*
  For the map to be displayed, the googleMap var must be
  appended to #mapDiv in resumeBuilder.js.
  */
  map = new google.maps.Map(document.querySelector('#map'), mapOptions);


  /*
  locationFinder() returns an array of every location string from the JSONs
  written for bio, education, and work.
  */
  function locationFinder() {

    // initializes an empty array
    var locations = [];

    // adds the single location property from bio to the locations array
    locations.push(bio.contacts.location);

    // iterates through school locations and appends each location to
    // the locations array. Note that forEach is used for array iteration
    // as described in the Udacity FEND Style Guide:
    // https://udacity.github.io/frontend-nanodegree-styleguide/javascript.html#for-in-loop
    education.schools.forEach(function(school){
      locations.push(school.location);
    });

    // iterates through work locations and appends each location to
    // the locations array. Note that forEach is used for array iteration
    // as described in the Udacity FEND Style Guide:
    // https://udacity.github.io/frontend-nanodegree-styleguide/javascript.html#for-in-loop
    work.jobs.forEach(function(job){
      locations.push(job.location);
    });

    return locations;
  }

  /*
  createMapMarker(placeData) reads Google Places search results to create map pins.
  placeData is the object returned from search results containing information
  about a single location.
  */
  function createMapMarker(placeData) {

    // The next lines save location data from the search result object to local variables
    var lat = placeData.geometry.location.lat();  // latitude from the place service
    var lng = placeData.geometry.location.lng();  // longitude from the place service
    var name = placeData.formatted_address;   // name of the place from the place service
    var bounds = window.mapBounds;            // current boundaries of the map window


    // infoWindows are the little helper windows that open when you click
    // or hover over a pin on a map. They usually contain more information
    // about a location.
    var infoWindow = new google.maps.InfoWindow({
      content: name
    });

    // marker is an object with additional data about the pin for a single location
    var marker = new google.maps.Marker({
      map: map,
      position: placeData.geometry.location,
      title:  name
    });


    // hmmmm, I wonder what this is about...
    marker.addListener('click', function() {
      // your code goes here!
       infowindow.open(map, marker);
    });

    // this is where the pin actually gets added to the map.
    // bounds.extend() takes in a map location object
    bounds.extend(new google.maps.LatLng(lat, lng));
    // fit the map to the new marker
    map.fitBounds(bounds);
    // center the map
    map.setCenter(bounds.getCenter());
  }

  /*
  callback(results, status) makes sure the search returned results for a location.
  If so, it creates a new map marker for that location.
  */
  function callback(results, status) {
    if (status == google.maps.places.PlacesServiceStatus.OK) {
      createMapMarker(results[0]);
    }
  }

  /*
  pinPoster(locations) takes in the array of locations created by locationFinder()
  and fires off Google place searches for each location
  */
  function pinPoster(locations) {

    // creates a Google place search service object. PlacesService does the work of
    // actually searching for location data.
    var service = new google.maps.places.PlacesService(map);

    // Iterates through the array of locations, creates a search object for each location
      locations.forEach(function(place){
      // the search request object
      var request = {
        query: place
      };

      // Actually searches the Google Maps API for location data and runs the callback
      // function with the search results after each search.
      service.textSearch(request, callback);
    });
  }

  // Sets the boundaries of the map based on pin locations
  window.mapBounds = new google.maps.LatLngBounds();

  // locations is an array of location strings returned from locationFinder()
  locations = locationFinder();

  // pinPoster(locations) creates pins on the map for each location in
  // the locations array
  pinPoster(locations);

}

/*
Uncomment the code below when you're ready to implement a Google Map!
*/

// Calls the initializeMap() function when the page loads
window.addEventListener('load', initializeMap);

// Vanilla JS way to listen for resizing of the window
// and adjust map bounds
window.addEventListener('resize', function(e) {
  // Make sure the map bounds get updated on page resize
 map.fitBounds(mapBounds);
});

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Answer 1

您正尝试在此处创建infoWindow对象：

// infoWindows are the little helper windows that open when you click
// or hover over a pin on a map. They usually contain more information
// about a location.
var infoWindow = new google.maps.InfoWindow({
  content: name
});

然后使用它（标记点击后显示消息）

// hmmmm, I wonder what this is about...
marker.addListener('click', function() {
  // your code goes here!
   infowindow.open(map, marker);
});

但要仔细看看你的变量： infoWindow !== infowindow（信W）

浏览器不知道， w indow是什么信息，并且出现错误。

在此处阅读有关JS中变量命名的更多信息：

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Grammar_and_types#Declarations

Answer 2

我在试图调试一些我从Hasam正在绘制的Udacity教程（API入门）中复制的代码时遇到了这个问题。我的代码，从视频本身复制，缺少一些关键行，并且无法正常运行。教程的“资源”没有代码的副本。我最终在Github上找到了一个很好的代码副本：https://github.com/udacity/ud864。当我写这个答案时，我发现隐藏在Udacity教程页面本身的一些底部的相同链接。