Any way to wrap spooky in a promise?

[jamesaspence]

I'm hoping to achieve something like this:

function createSpooky() {
    return new Promise(function (resolve) {
        var spooky = new Spooky(opts, function (err) {
            if (err) {
                var e = new Error('Failed');
                e.details = err;
                throw e;
            }

            resolve(spooky)
        });
    });
}

That way, I could do something like:

createSpooky().then(function (spooky) {
    spooky.open('https://google.com');
    //Initialize the rest of our spooky steps here!
});

Every time I try to resolve spooky via that promise, however, I get an error (kinda); Uncaught, unspecified "error" event. ([object Object]).

I'm not sure how to continue from here. Maybe this is my lack of understanding promises fully, or spooky's limitations, but is such a thing possible? Am I going about it completely wrong? I'm just hoping to avoid callback hell and I really like to chain my thens (i.e. createSpooky().then(doStuff).then(doMoreStuff)

[jamesaspence]

After adding error logs, I was able to get this error:

{ id: 1,
  code: -32603,
  message: 'Expected maximum of 1 arguments, but got 2' }

[LM1LC3N7]

@jamesaspence , how did you use the callback ?

I have been trying :

function(callback, err){
    // spooky code
    // if err : err(error);
    // else : callback(datas);
}

But I have errors because callback and err seems to not be accessible from spooky.then or spooky.thenEvaluate or again spooky.run.

Thanks

EDIT
Found how to do that!

I use this.emit with an event listener.

//
// My Function
//
function mySpookyFunction(callback){
    // ...
    // Spooky Code
    // ...

    spooky.then(function(){
        // Code
        this.emit('return', myLocalVariable);
    }

    // ...
    // Spooky Code
    // ...

    spooky.on('return', function(res){
        callback(res);
    }

});


//
// Now we call the function and get the result.
//
mySpookyFunction(function(res){
    console.log("Datas received !");
    console.log(res);
});

[betonimig]

@jamesaspence, try: resolve({spooky: spooky})

[mschultheiss83]

UPDATE:Working Example

var Spooky = require('spooky');

var spooky = new Spooky({
  child: {
    transport: 'http'
  },
  casper: {
    pageSettings: {
      loadImages: false,
      loadPlugins: false
    },
    logLevel: "debug",
    verbose: true
  }
}, function (err) {
  if (err) {
    var e = new Error('Failed to initialize SpookyJS');
    e.details = err;
    throw e;
  }
  spooky.start();

  spooky.then(function emitHelloMySpookyFunction() {
    this.emit('hello', 'mySpookyFunction');
  });

  spooky.run();
});

var mySpookyFunction = function mySpookyFunction(resolve) {
  // ...
  // Spooky Code
  // ...
  var myLocalVariable = {url: "https://github.com/SpookyJS/SpookyJS/issues/202"};
  var transport = {myLocalVariable: myLocalVariable};
  spooky.then([transport, function emitReturn() {
    // Code
    this.emit('return', myLocalVariable);
  }]);

  // ...
  // Spooky Code
  // ...

  spooky.on('return', function onResolve(res) {
    resolve(res);
  });
};

spooky.on('error', function onError(e, stack) {
  console.error(e);
  if (stack) {
    console.log(stack);
  }
});

//*
// Uncomment this block to see all of the things Casper has to say.
// There are a lot.
// He has opinions.
spooky.on('console', function onConsole(line) {
  console.log(line);
});
//*/

spooky.on('getPageContent', function () {
  spooky.then(function onGetPageContent() {
    var content = this.getPageContent();
    //this.log(content, 'debug');
    this.emit('return', {content: content});
  });
});


spooky.on('hello', function onHello(greeting) {
  console.log('greeting ' + greeting);
  if (greeting == 'mySpookyFunction') {
    mySpookyFunction(function onResolve(res) {
      /** with each this.emit('return', we come across this line, see spooky.on('getPageContent', [...] */
      console.log("Data received !");
      if (res.url) {
        console.log(res);
        spooky.open(res.url);
        spooky.then(function emitGetPageContent() {
          this.emit('getPageContent');
        });
      }
      if (res.content) {
        console.log('res.content');
      }
    });
  }
});

spooky.on('log', function (log) {
  if (log.space === 'remote') {
    console.log(log.message.replace(/ \- .*/, ''));
  }
});

[mschultheiss83]

UPDATE: Working Promise Example
@jamesaspence @betonimig thanks for the idea

var Spooky = require('spooky');
//var Promise = require('bluebird');

var opts = {
  child: {
    transport: 'http'
  },
  casper: {
    pageSettings: {
      loadImages: false,
      loadPlugins: false
    },
    logLevel: "debug",
    verbose: true
  }
};

function createSpooky() {
  return new Promise(function (resolve, reject) {
    var spooky = new Spooky(opts, function (err) {
      if (err) {
        var e = new Error('Failed to initialize SpookyJS');
        e.details = err;
        reject(e);
      }

      resolve({spooky: spooky});
    });
  });
}

createSpooky()
  .then(function appendErrorEvent(res) {
    console.log('appendErrorEvent', Object.getOwnPropertyNames(res));
    if (res.spooky) {
      res.spooky.on('error', function (e, stack) {
        console.error(e);
        if (stack) {
          console.log(stack);
        }
      });
      return res;
    }
    throw new Error('Failed to appendErrorEvent');
  })
  .then(function appendLogEvent(res) {
    console.log('appendLogEvent', Object.getOwnPropertyNames(res));
    if (res.spooky) {
      res.spooky.on('log', function (log) {
        if (log.space === 'remote') {
          console.log(log.message.replace(/ \- .*/, ''));
        }
      });
      return res;
    }
    throw new Error('Failed to appendLogEvent');
  })
  .then(function appendConsoleEvent(res) {
    console.log('appendConsoleEvent', Object.getOwnPropertyNames(res));
    if (res.spooky) {
      res.spooky.on('console', function (line) {
        console.log(line);
      });
      return res;
    }
    throw new Error('Failed to appendConsoleEvent');
  })
  .then(function runMainFunction(res) {
    console.log('runMainFunction', Object.getOwnPropertyNames(res));
    if (res.spooky) {
      res.spooky.start(
        'http://en.wikipedia.org/wiki/Spooky_the_Tuff_Little_Ghost');
      res.spooky.then(function emitHello() {
        var documentTitle = this.evaluate(function () {
          return document.title;
        });
        this.emit('hello', 'Hello, from ' + documentTitle);
      });
      res.spooky.run();
      return res;
    }
    throw new Error('Failed to runMainFunction');
  })
  .then(function appendHelloEvent(res) {
    console.log('appendHelloEvent', Object.getOwnPropertyNames(res));
    if (res.spooky) {
      res.spooky.on('hello', function onHello(greeting) {
        console.log('greeting ' + greeting);
      });
      return res;
    }
    throw new Error('Failed to appendHelloEvent');
  })
  .catch(function (err) {
    console.error(err);
  });

i hope this helps