polymerfire/firebase-query transaction complete event

Question

Very new to Polymer and Polymerfire. I couldn't find an answer here so hoping I can get help here. The basic question I have is "how do I work with the data that polymerfire/firebase-query sends?" Note I'm using polymerfire version 0.9.4, and polymer is version 1.4.0.

I can load my data from Firebase no problem using Firebase query, however some of the values are raw numbers that I need to convert to user friendly information. For example I have time stored in ms that I want to convert to a date, and a numeric field that indicates the "type" of data that is stored and I want to show an icon for it, not just a raw number. I figured my best option would be to use the transactions-complete promise or an observer. Both fire but neither seems to give me access to the data. The Observer's newData is an empty array, and transactions-complete.. well I don't really know what to do with that when the promise fires. Below is my relevant code. I also tried using notify: true, but I seem to not be grasping the concept correctly.

<firebase-query
    id="query"
    app-name="data"
    path="/dataPath"
    transactions-complete="transactionCompleted"
    data="{{data}}">
</firebase-query>

<template is="dom-repeat" items="{{data}}">
  <div class="card">
    <div>Title: <span>{{item.title}}</span></div>
    <div>Date Created: <span>{{item.dateCreated}})</span></div>
    <div>Date Modified: <span>{{item.dateModified}}</span></div>
    <div>Status: <span>{{item.status}}</span></div>
  </div>
</template>

Polymer({
  is: 'my-view1',
  properties: {
      data: {
        notify: true,
        type: Object,
        observer: 'dataChanged'
      }
  },
  dataChanged: function (newData, oldData) {
    console.log(newData[0]);
    // do something when the query returns values?
  },
  transactionCompleted: new Promise(function(resolve, reject) {
 //        how can I access "data" here? 
  })`

What version of polymerfire are you using? – Seth Aug 01 '16 at 18:36 — Seth, Aug 01 '16 at 18:36
oops sorry, polymerfire is 0.9.4, and polymer is 1.4.0 – Terry Aug 02 '16 at 00:03 — Terry, Aug 02 '16 at 00:03

score 1 · Accepted Answer · answered Aug 26 '16 at 22:38

I wound up going another way entirely, which seemed to be a cleaner approach to what I was doing anyways. I broke it down into separate components. This way when the detail component was loaded, the ready function would allow me to adjust the data before it got displayed:

list.html:

<firebase-query
    id="query"
    app-name="data"
    path="/dataPath"
    data="{{data}}">
</firebase-query>

<template is="dom-repeat" items="{{data}}">
   <my-details dataItem={{item}}></my-details>
</template>

details.html

 <template>
    <div id="details">
      <paper-card heading="{{item.title}}">
        <div class="card-content">
          <span id="description">{{item.description}}</span><br/><br/>
          <div class="details">Date Created: <span id="dateCreated">{{item.dateCreated}}</span><br/></div>
          <div class="details">Last Modified: <span id="dateModified">{{item.dateModified}}</span><br/></div>
          <div class="status"><span id="status">{{item.status}}</span><br/></div>
        </div>
      </paper-card>

  </template>

Then in the javascript ready function I can intercept and adjust the data accordingly:

Polymer({
  is: 'my-details',
  properties: {
      item: {
        notify: true,
      },
  },
 ready: function() {
    this.$.dateModified.textContent = this.getDate(this.item.dateModified);
    this.$.dateCreated.textContent = this.getDate(this.item.dateCreated);
    this.$.status.textContent = this.getStatus(this.item.status);
  },

score 0 · Answer 2 · answered Aug 25 '16 at 14:07

Try the following changes:

Take out the transactions-completed attribute - it is only relevant when the query is updating data to Firebase
Change the dom-repeat template to get it's items attribute from convertedData - this allows you to do the data conversions to## Heading ## the results of the firebase-query

<firebase-query
    id="query"
    app-name="data"
    path="/dataPath"
    data="{{data}}">
</firebase-query>

<template is="dom-repeat" items="{{convertedData}}">
  <div class="card">
    <div>Title: <span>{{item.title}}</span></div>
    <div>Date Created: <span>{{item.dateCreated}})</span></div>
    <div>Date Modified: <span>{{item.dateModified}}</span></div>
    <div>Status: <span>{{item.status}}</span></div>
  </div>
</template>

Add a convertedData property to do your data conversions from data which has the raw data
Change the observer syntax as per the example. This sets up the observer to to observe for changes to deep property values which results in the observer method being fired - see: https://www.polymer-project.org/1.0/docs/devguide/observers#deep-observation
In the observer method you can populate the convertedData object from the data object which should then render the content

Polymer({
  is: 'my-view1',
  properties: {
      data: {
        notify: true,
        type: Object
      },
      convertedData: {
        notify: true,
        type: Object
      }
  },
  // observer syntax to monitor for deep changes on "data"
  observers: [
      'dataChanged(data.*)'
  ]
  dataChanged: function (newData, oldData) {
    console.log(newData);
    // convert the "newData" object to the "convertedData" object
  }
}

polymerfire/firebase-query transaction complete event

2 Answers2