have to filter out messages with a length shorter then 50

[Roelof Wobben]

Hello,

I try to learn functional javascript by following the functonial workshop of nodeschool.

Now I have to filter out all the messages which lenght are shorter then 50.

So I thought this would work :

~~~

module.exports = function getShortMessages(messages) {

    function small_message(item)

    { return item.length < 50 ; }




    messages.map(function(message)

     { return small_message(message) }) }

but when I test it I see a empty array as answer  

Can someone explain where my thinking took the wrong path ?

Roelof

[Scott Ganyo]

Hey Roelof,

I don’t see you returning the results of your map anywhere. I would expect to see this:

  return messages.map( …

Best,

Scott

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[Adrien Risser]

Filter is what you're looking for.

https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Array/filter

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[Roelof Wobben]

I thought that this part took part of that : { return small_message(message) }) }

there I return the output of the filter.

Roelof

Op dinsdag 20 januari 2015 17:30:44 UTC+1 schreef Scott Ganyo:

[Roelof Wobben]

I try to use it .

When I do this :

~~~

module.exports = function getShortMessages(messages) {
   
    function smallerfifty(element) {
        return element.length > 50;
        }
   
    return messages.filter(smallerfifty);
              
    }

~~~

I see a empty array.

Op dinsdag 20 januari 2015 17:30:56 UTC+1 schreef Adrien Risser:

[Scott Ganyo]

That too. :)  And... you could simplify your function if you wish:

module.exports = function getShortMessages(messages) {

    function small_message(item) { return item.length < 50; }

    return messages.filter(small_message);

}

Scott

To view this discussion on the web visit https://groups.google.com/d/msgid/nodejs/CAKGrCFhq%2BFFN655s2A4QbJ5fmPUK%3DNxOU1h9cxRAPsLekJkEYg%40mail.gmail.com.

[Alexander Behrens]

Also, you can pass the function as an argument directly:

return messages.filter(small_message);

To view this discussion on the web visit https://groups.google.com/d/msgid/nodejs/CAKGrCFhq%2BFFN655s2A4QbJ5fmPUK%3DNxOU1h9cxRAPsLekJkEYg%40mail.gmail.com.

[Roelof Wobben]

oke,

But still my answer is failing . See this output :

~~~

ACTUAL                             EXPECTED                                        

------                             --------                                        

"[]"                            != "[ 'Et anim veniam dolor ipsum consectetur.',"  

""                              != "  'Magna velit non do ea aliquip nulla minim.',

"                                                                                  

null                            != "  'Minim magna proident consectetur dolore.'," 

null                            != "  'Minim sint minim reprehenderit laboris minim

.',"                                                                               

null                            != "  'Nisi duis exercitation nisi tempor ex magna.

',"                                                                                

null                            != "  'Dolor nulla deserunt cupidatat pariatur.'," 

null                            != "  'Aute laboris eiusmod nulla do cupidatat.'," 

null                            != "  'Labore non sit mollit irure labore.',"      

null                            != "  'Anim non ullamco culpa ea sint do sunt.',"  

null                            != "  'Non amet duis dolore officia anim.',"       

null                            != "  'Irure ex commodo amet id tempor do cillum.',

"                                                                                  

null                            != "  'Laborum fugiat sunt eu veniam aute.' ]"     

null                            != ""                                              

# FAIL                                              

~~~

So something is not right here.

Roelof

Op dinsdag 20 januari 2015 17:48:21 UTC+1 schreef Alexander Behrens:

[Roelof Wobben]

the input variable looks like this :

[ { message: 'Cillum quis laborum incididunt aliqua est et consectetur ipsum elit d

eserunt.' },                                                                       

  { message: 'Dolor incididunt velit sit deserunt laboris sunt nostrud cillum Lorem

 sit occaecat dolore aute ex.' },                                                  

  { message: 'Id fugiat veniam do eu.' },                                          

  { message: 'Consequat id non nulla culpa dolore eu irure deserunt.' },           

  { message: 'Mollit qui elit tempor eiusmod eu.' },                               

  { message: 'Aliquip quis aute cupidatat adipisicing irure nisi consectetur.' },  

  { message: 'Adipisicing ea cupidatat quis sunt eu id velit voluptate officia cill

um elit aute aliqua.' },                                                           

  { message: 'Qui incididunt aute eiusmod Lorem cillum.' },                        

  { message: 'Sunt non ut eiusmod id magna sunt culpa labore aliquip.' },          

  { message: 'Mollit exercitation sunt esse reprehenderit consequat laboris irure i

n dolore non.' },                                                                  

  { message: 'Incididunt Lorem minim non sunt est mollit non do nulla elit qui ipsu

m.' },                                                                             

  { message: 'Ea exercitation occaecat nulla irure eiusmod pariatur enim ipsum duis

 pariatur pariatur.' },                                                            

  { message: 'Consequat ad labore occaecat magna.' },                              

  { message: 'Sunt commodo veniam consequat ea exercitation incididunt esse nostrud

 elit labore ipsum aliquip.' },                                                    

  { message: 'Do deserunt consectetur id pariatur culpa.' },                       

  { message: 'Magna consectetur irure consequat duis consequat dolore duis exercita

tion eiusmod id aute exercitation.' } ]   

Maybe on some way use the map function so every item in the array is used. ?

Op dinsdag 20 januari 2015 17:48:21 UTC+1 schreef Alexander Behrens:

Also, you can pass the function as an argument directly:

return messages.filter(small_message);

[Alexander Behrens]

@Roloef: Ist your sample array full of short texts? Because your example filters out any short text. Therefore your returning array is empty. You have to change the condition from element.length > 50 to element.length <= 50

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[Roelof Wobben]

you are right. I have misread the challenge

Still one problem :

The output now looks like this :

~~~

[ { message: 'Cupidatat reprehenderit qui dolor ex labore amet.'  } ,

~~~

where the output must look like this :

~~~

[  message: 'Cupidatat reprehenderit qui dolor ex labore amet.' ,

~~~

So I think I need to use map to fetch the messages one by one or is there another way .

Roelof

Op dinsdag 20 januari 2015 18:34:44 UTC+1 schreef Alexander Behrens:

[Alexander Behrens]

Change return item.length < 50 to return item.message.length < 50

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[Roelof Wobben]

I already did .

I have now this

~~~

module.exports = function getShortMessages(messages) {
   
    function smallerfifty(element) {
        return element.message.length < 50;
     }
   
    return messages.filter(smallerfifty)
 
              
}

~~~

and this output :

~~~

[ { message: 'Eiusmod adipisicing esse labore magna elit irure.' },                                      

  { message: 'Amet esse excepteur mollit excepteur.' },  

]

~~~

where it schould be

~~~

[  message: 'Eiusmod adipisicing esse labore magna elit irure.' ,                                      

   message: 'Amet esse excepteur mollit excepteur.' ,  

~~~

Op dinsdag 20 januari 2015 19:23:10 UTC+1 schreef Alexander Behrens:

[Roelof Wobben]

Solved this one with a little try and error.

Roelof

Op dinsdag 20 januari 2015 19:37:41 UTC+1 schreef Roelof Wobben: