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如何将承诺值返回给调用函数?

alexa javascript

Hackbrew · 技术社区 · 8 年前

我理解的方式是,我正在调用一个同步函数“httpget”,它应该返回一个承诺。该函数似乎正在工作,因为它通过console.log语句成功地从airtable中获取了所有数据,但在.then()方法中得到了任何响应。

这里是我调用“httpget”函数的地方:

async handle(handlerInput) {
    let speechText = '';
    console.log('Going to fetch Airtable data');
    await httpGet(base).then((response) => {
      console.log('have promise')    
    }).catch((err) => {
      //set an optional error message here
      console.log('do not have promise')
      //speechText = 'there is an error ' + err.message;
    }); 
    speechText = `Container ID ` + contID + ` is a ` + bincolor + `, ` + gallons + ` located in ` + binloc ;        

    console.log('speechText = ' + speechText);

    return handlerInput.responseBuilder
      .speak(speechText)
      .reprompt(speechText)
      .withSimpleCard('Warehouse Inventory', speechText)
      .getResponse();
};

下面是正在调用的httpget函数:

async function httpGet(options) {
  // return new pending promise
  return new Promise((resolve, reject) => {    

        base('Bins').select({
          // Selecting a record in Grid view:
          maxRecords: 1,
          view: "Grid view"
        }).eachPage(function page(records, fetchNextPage) {
          // This function (`page`) will get called for each page of records.

          records.forEach(function(record) {
              console.log('Container ID: ', record.get('Container ID'));
              console.log('Gallons: ', record.get('Gallons'));        
              console.log('Bin Color: ', record.get('Color'));
              console.log('Location: ', record.get('Location'));        
              console.log('Imperfections: ', record.get('Imperfections'));
              var contID = record.get('Container ID');
              var gallons = record.get('Gallons');
              var bincolor = record.get('Color');
              var binloc = record.get('Location');
              var imper = record.get('Imperfections');

          });

          // To fetch the next page of records, call `fetchNextPage`.
          // If there are more records, `page` will get called again.
          // If there are no more records, `done` will get called.
          fetchNextPage();

      }, function done(err) {
          if (err) { 
            console.error(err); return; 
          }
      });    
  });
}

最后,我尝试获取varaibles contid、gal、bincolor、binloc和imper中存储的值。我怎样才能做到这一点?

2 回复 | 直到 8 年前

vkarpov15 8 年前

httpGet() resolve({ contID, gallons, /* ... */ }) then((response) => {}) response contID gallons this blog post

Bash Lord 8 年前

    httpGet = (options) => {
    return new Promise((resolve, reject) => {
        resolve(/*return your result here*/);
        reject(/*return error here*/);
    });
}


//inside of some function
let firstResult, secondResult;
httpGet(argument)
    .then(result => {
        firstResult = result;
        //you can chain promise if u need
        return httpGet(secondArgument)
    })
    .then(result => {
        secondResult = result;
    })
    .then(() => {
        //here you can acces firstResult, secondResult variables, pass them to some function as arguments
    })
    .catch((error)=>{})