Node js - How to return array multidimensional

Question

I need to create an array with this structure:

[
 { 
   position: 2,
   family: 9404,
   part: [ 'article1', 'article2', 'article3' ]
 },
 {
   position: 3,
   family: 9405,
   part: [ 'article4', 'article5', 'article6' ] 
  }
]

So i have a form where i select the parts that i want and send the families to get url.In the getter function i do a for to get the articles of each family and i want to query a select of articles and a select of positions. After that i try to push each array to a main array but i can't, show me undefined. How can i do this kind of operations?

I'm new with node and express and this is the first time that i have to do that.

My code:

 getFamilies(req, res)
  {
    console.log(req.params.data);
    var parsedData = JSON.parse(req.params.data);
    var compounds = parsedData[0].compounds;
    var supplier = parsedData[0].supplier;
    var families = parsedData[0].families;
    console.log(parsedData[0].compounds.length);

    var position = [];

    var data = [];
    var parts = [];
    for (var i = 0; i < compounds.length; i++)
    {
      parts.push(request.query("SELECT st.ref, st.design FROM st WHERE familia ='"+families[i]+"'"));
      position.push(request.query("SELECT u_order FROM u_part WHERE u_familia='"+families[i]+"'"));
    }

    return Promise.all(parts, position, families).then(function(listOfResults)
    {
      //add parts, position and families to data[]
      var data = [];

      //console.log(data);
      console.log(listOfResults);
      console.log("done");
      //return listOfResults;
      res.render('view2', {teste: data});
    }).catch(function(err)
    {
        // ... query error checks
        console.log(err);
    });
  }

In promise just print the first parameter "parts" and if i put the [parts, position, families] give me promise pending. And how can i put the data in the structure that i show above.

parseData:

[
 {
   "compounds": ["8"],
   "supplier": ["sup"],
   "families": ["9305"]
  }
]

Please teach me how can i do this kind of operations.

Thank you

Answer 1

You incorrectly use Promise.all , it takes array of promises

return Promise.all([Promise.all(parts), Promise.all(position)]).then(function(listOfResults){
  var partResult = listOfResults[0];
  var positionResult = listOfResults[1];
  var data = [];
  for (var i=0; i<families.length; i++) {
     var family = families[i];
     var pos = positionResult[i];
     var parts = partResult; // logic to extract parts for current family
     data.push({family: family, position: pos, parts: parts})
  }
  console.log(data);
})

Answer 2

• Not sure why you're passing families to Promise.all families seems to just be an array of data from taken from the query
• Promise.all takes an array of promises in input, and you're passing an array of arrays of promises and of data...
• you should never build SQL queries like this. This is a big flaw for SQL injection (but that's another question)

So do:

Promise.all([...parts, ...position]) or if you're not using ES6 syntax Promise.all(parts.concat(position))

and fix your SQL!

====

Final code could look like:

getFamilies = (req, res) => {
  var families = JSON.parse(req.params.data)[0].families;

  var positions = [];

  var data = [];
  var parts = [];
  families.forEach(family => {
    // see http://stackoverflow.com/a/7760578/2054629 for mysql_real_escape_string
    parts.push(request.query("SELECT st.ref, st.design FROM st WHERE familia ='"+mysql_real_escape_string(family)+"'"));
    positions.push(request.query("SELECT u_order FROM u_part WHERE u_familia='"+mysql_real_escape_string(family)+"'"));
  });

  return Promise.all([Promise.all(parts), Promise.all(positions)]).then(listOfResults => {
    var [partResult, positionResult] = listOfResults;

    var data = families.map((family, i) => {
      var pos = positionResult[i];
      var parts = partResult[i];
      return {family: family, position: pos, parts: parts};
    });
    res.render('view2', {teste: data});
  }).catch(err => {
      // ... query error checks
      console.log(err);
  });
};

Answer 3

Promise.all()接受一个promise数组，好像您正在传递多个数组。