類型錯誤屬性，則是不確定的

Question

Var Map, CachedGeoJson; 

var promise = that.map.data.loadGeoJson('https://api.myjson.com/bins/31e3j'); 

promise.then(function(data) { 
    cachedGeoJson = data; 

    map.data.addGeoJson(
     'https://api.myjson.com/bins/31e3j', 
     { idPropertyName: "id"} 
    ); 

Answer 1

您需要關閉功能，修復這樣的語法：

Var Map, CachedGeoJson; 

var promise = that.map.data.loadGeoJson('https://api.myjson.com/bins/31e3j'); 

promise.then(function(data) { 
    cachedGeoJson = data; 

    map.data.addGeoJson(
     'https://api.myjson.com/bins/31e3j', 
     { idPropertyName: "id"} 
    ); 
}); 

Answer 2

你可以嘗試創建一個不同的功能，因爲谷歌loadGeoJson創建承諾對象不返回承諾對象。

function loadGeoJson(url, options) { 
    var promise = new Promise(function (resolve, reject) { 
     try { 
     that.map.data.loadGeoJson(url, options, function (features) { 
      resolve(features); 
     }); 
     } catch (e) { 
     reject(e); 
     } 
    }); 
    return promise; 
} 

var promise = loadGeoJson('studs.json'); 

promise.then(function (features) { 
    map.data.addGeoJson(
     'https://api.myjson.com/bins/31e3j', 
     { idPropertyName: "id"} 
    ); 
}); 

Answer 3

您可以檢查承諾中存在哪些屬性。

for (var property in promise) { 
    if (promise.hasOwnProperty(property)){ 
     alert(property); 
    } 
}