Format object with array of objects in properties - variable scope problem

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Good morning,

I have a problem with returning a webservice, I make a query to get Categories, and then another to get the items in that category. The goal is to set a return on the pattern: 

{
 "categoryId" : 1,             <--- resultado da query 1
 "category" : "Alimentos",     <--- resultado da query 1
 "items" : [{
             "eventItemListId": 34,
             "itemId": 31,
             "item": "blabla",
             "amountNeeded": 4,
             "unityId": 1,
             "unity": "Un",
             "addedBy": "1"
            },
            (...)              <--- Este array de objetos vem da query 2
  ]
}

My webservice is as follows: 

getEventItemListByCategory: (eventId) => {
  return new Promise((resolve, reject) => {
    const { connection, errorHandler } = deps
    const sqlData = [eventId]
    connection.query(process.env.QUERY_CATEGORY_ALL, sqlData, (error, results) => {
      if (error) {
        errorHandler(error, 'Falha ao obter lista de categorias', reject)
        return false
      }
      var ret = []
      for (let i = 0; i < results.length; i++) {
          let row = results[i]
        console.log(row.id + ' | ' + row.description)
        const sqlData = [eventId, row.id]
        connection.query(process.env.QUERY_ITEM_EVENT_ITEMS_BY_CATEGORY, sqlData, (error, results) => {
          if (error) {
            errorHandler(error, 'Falha ao obter lista de itens evento', reject)
            return false
          }
          ret.push({
            categoryId: row.id,
            category: row.description,
            items: JSON.stringify(results)
          })
        })
        console.log(JSON.stringify(ret))
      }
      resolve({ eventItems: JSON.stringify(ret) })
    })
  })
}

In the line where I log into the console, the result is (apparently ok): 

[{"categoryId":1,"category":"Alimentos","items":"[  {"eventItemListId":34,"itemId":31,"item":"blabla","categoryId":1,"category":"Alimentos","amountNeeded":4,"unityId":1,"unity":"Un","addedBy":"1"},{"eventItemListId":36,"itemId":38,"item":"lalala","categoryId":1,"category":"Alimentos","amountNeeded":4,"unityId":1,"unity":"Un","addedBy":"1"},{"eventItemListId":5,"itemId":7,"item":"Linguiça","categoryId":1,"category":"Alimentos","amountNeeded":5,"unityId":4,"unity":"Kg","addedBy":"1"},{"eventItemListId":6,"itemId":10,"item":"Pão de alho","categoryId":1,"category":"Alimentos","amountNeeded":2,"unityId":2,"unity":"Pc","addedBy":"3"},{"eventItemListId":4,"itemId":5,"item":"Picanha","categoryId":1,"category":"Alimentos","amountNeeded":3,"unityId":4,"unity":"Kg","addedBy":"2"},{"eventItemListId":3,"itemId":3,"item":"Refrigerante","categoryId":1,"category":"Alimentos","amountNeeded":12,"unityId":5,"unity":"L","addedBy":"1"},{"eventItemListId":35,"itemId":32,"item":"Teste inclusão","categoryId":1,"category":"Alimentos","amountNeeded":10,"unityId":1,"unity":"Un","addedBy":"1"},{"eventItemListId":1,"itemId":1,"item":"Vodka","categoryId":1,"category":"Alimentos","amountNeeded":6,"unityId":3,"unity":"Gf","addedBy":"1"},{"eventItemListId":2,"itemId":2,"item":"Whisky","categoryId":1,"category":"Alimentos","amountNeeded":6,"unityId":3,"unity":"Gf","addedBy":"2"}]"},
{"categoryId":2,"category":"Infraestrutura","items":"[
  {"eventItemListId":7,"itemId":12,"item":"Caixa de som","categoryId":2,"category":"Infraestrutura","amountNeeded":2,"unityId":1,"unity":"Un","addedBy":"3"},{"eventItemListId":10,"itemId":20,"item":"Carvao","categoryId":2,"category":"Infraestrutura","amountNeeded":2,"unityId":2,"unity":"Pc","addedBy":"2"},{"eventItemListId":11,"itemId":21,"item":"Gelo","categoryId":2,"category":"Infraestrutura","amountNeeded":8,"unityId":2,"unity":"Pc","addedBy":"2"}]"},
{"categoryId":3,"category":"Outros","items":"[
{"eventItemListId":8,"itemId":18,"item":"Baralho","categoryId":3,"category":"Outros","amountNeeded":2,"unityId":1,"unity":"Un","addedBy":"3"},{"eventItemListId":9,"itemId":19,"item":"Narguile","categoryId":3,"category":"Outros","amountNeeded":1,"unityId":1,"unity":"Un","addedBy":"3"}]"}]

But webservice, being tested on Postman does not return value. When doing a test by moving the console.log out of the scope it is, just before the 'resolve', it actually logs empty arrays.

I've already done the test of changing the location of the variable declaration in all blocks, but I can not mount the return as desired until the final return scope. Can anyone explain where the error is exactly?

Thank you.

    
asked by anonymous 10.09.2018 / 03:19

1 answer

0

You're solving the promise before you finish the querys within for . Try to verify if it is the last iteration before returning the response to the client. The code would look like this: 

for (let i = 0; i < results.length; i++) {
    let row = results[i]
    console.log(row.id + ' | ' + row.description)
    const sqlData = [eventId, row.id]
    connection.query(process.env.QUERY_ITEM_EVENT_ITEMS_BY_CATEGORY, sqlData, (error, results) => {
        if (error) {
            errorHandler(error, 'Falha ao obter lista de itens evento', reject)
            return false
        }
        ret.push({
            categoryId: row.id,
            category: row.description,
            items: JSON.stringify(results)
        })

        // Validar indice antes de resolve a promise
        if (i === results.length - 1) {
            console.log(JSON.stringify(ret))
            resolve({ eventItems: JSON.stringify(ret) })
        }
    })
}

The connection.query command responds asynchronously, so you should make sure that they are finalized before returning the array to the client. So it would be ideal to create a promise list for each query execution and resolve the main promise at the end of all promises using promise.all

    
10.09.2018 / 04:06
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