如何使用流星允许3个电话承诺

Question

我想避免回调地狱，所以我创立了承诺，但我有点卡住了。

我需要getAllDataSource - >createDashboard - >`sendDashboard``

因此，代码为：

var call = Promise.promisify(Meteor.call, Meteor); 

var calls = call(getAllDataSource()). 
      then(call.bind(Meteor, createDashboard())). 
      then(call.bind(Meteor, sendDashboard())); 

calls.then(function(resThree){ 
    console.log("Got Response!", resThree); 
}).catch(function(err){ 
    console.log("Got Error", err); 
}); 

但我有点与第一VAR call我想我需要丢失改变它，但用什么？那么如何知道getAllDataSource何时完成？

var allDataSources; 
getAllDataSources = Meteor.bindEnvironment(function(){ 
    HTTP.call("GET", 'http://localhost:3000/api/datasources', { 
      headers: { 
       'Accept': 'application/json', 
       'Content-Type': 'application/json', 
       'Authorization': 'Bearer eyJrIjoic2RRbU9oM2Rkbmc0bHZUSjVlTjBPckRVNlplSW1DYzEiLCJuIjoibG9jYWxob3N0X2FkbWluX2tleSIsImlkIjoxfQ==', 
      }, 
     }, 
     function(error, result) { 
      if (!error) { 
       allDataSources = result.data; 
      } else { 
       console.error(error); 
      } 
     }); 
}); 

var sendme; 
createDashboard = Meteor.bindEnvironment(function(){ 
    for (var i = 0; i < 5; i++) { 
    console.log("I have " + i + " apples in " + allDataSources); 
    sendme = "hihihih"; 
    } 
}); 

sendDashboard = Meteor.bindEnvironment(function(){ 
    for (var i = 0; i < 7; i++) { 
    console.log("I have " + i + " cats with " + sendme); 
    } 
}); 

当创建结果时它会自动转到方法2吗？

感谢您的帮助

[编辑]这实际上给我在控制台上：

Got Error { [Error: Method 'undefined' not found [404]] 
I20170209-10:39:30.990(1)? error: 404, 
I20170209-10:39:30.991(1)? reason: 'Method \'undefined\' not found', 
I20170209-10:39:30.991(1)? details: undefined, 
I20170209-10:39:30.991(1)? message: 'Method \'undefined\' not found [404]', 
I20170209-10:39:30.991(1)? errorType: 'Meteor.Error' } 

[EDIT2] 其次@ymz的答案后，我得到这个错误：

Got Error { [Error: Method '[object Object],[object Object],[object Object],[object Object]' not found [404]] 
I20170209-11:23:48.154(1)? error: 404, 
I20170209-11:23:48.154(1)? reason: 'Method \'[object Object],[object Object],[object Object],[object Object]\' not found', 
I20170209-11:23:48.154(1)? details: undefined, 
I20170209-11:23:48.154(1)? message: 'Method \'[object Object],[object Object],[object Object],[object Object]\' not found [404]', 
I20170209-11:23:48.154(1)? errorType: 'Meteor.Error' } 

而且我认为它来自var calls = call(data).then .... // proceed from here，因为getAllDataSource()在这里放入一个数组在data这里。我需要多一点帮助，请

Answer 1

所以尝试，并试图之后我做了这样的代码：

new Promise(function(resolve) { 
    console.log("step1") 
    // 1. first async task 
    HTTP.call("GET", 'http://localhost:3000/api/datasources', { 
      headers: { 
       'Accept': 'application/json', 
       'Content-Type': 'application/json', 
       'Authorization': 'Bearer 123', 
      }, 
     }, 
     function(error, result) { 
      if (!error) { 
       allDataSources = result.data; 
       console.log("step1.5" + allDataSources) 
       resolve(allDataSources); 
      } else { 
       console.error(error); 
      } 
     }); 

}).then(function(allDataSources) { 
    console.log("step2") 
    // 2. second async task 
    return new Promise(function(resolve) { 
     console.log("step 2.5" + resolve + allDataSources) 
     for (var dataSource = 0; dataSource < allDataSources.length; dataSource++) { 
     sendme = "sendme"; 
     } 
     resolve(sendme); 
    }); 

}).then(function(sendme) { 
    // 3. now we can render the products after two async tasks are done 
    console.log('Rending product ' + sendme); 
}); 

我想给一个巨大的谢谢@ymz谁帮我

Answer 2

这个问题是非常棘手，因为它失败，原因是2个不同的因素

为 Promise
1. 错误的做法
2. 错误的参考，同时使用异步代码

完整修复：

首次使用需要Bluebird Promise lib：

var Promise = require('bluebird'); 

二 - 一个回调

function whenDataArrive(data) 
{ 
    if (!data) return; 

    var calls = call(data).then .... // proceed from here 
} 

getAllDataSources = Meteor.bindEnvironment(function(id){ 
HTTP.call("GET", 'http://localhost:3000/api/datasources', { 
     headers: { 
      'Accept': 'application/json', 
      'Content-Type': 'application/json', 
      'Authorization': 'Bearer 123', 
     }, 
    }, 
    function(error, result) { 
     if (!error) { 
      whenDataArrive(result.data); 
     } else { 
      console.error(error); 
      whenDataArrive(); 
     } 
    }); 

}）处理您的异步代码;