Niklas Lang Niklas Lang - 1 month ago 11
JSON Question

Store returned values from the iron-ajax request in variables (Polymer)

I am working the first time with Polymers iron-ajax element and came across a problem which I believe is fairly simple to solve but I am unable to find a solution online.


I retrieve user details with the iron-ajax element and loop through it with the dom-repeat. The first and last name of a user are getting placed in a custom card element that I created to display users. Everything works fine except that I am unable to store the returned id value in a variable.
I am sure this is possible with the usage of data binding but I couldn't get it to work. And even when I try to get the value with getAttribute in my JavaScript it just returns null.


In the code below my iron-ajax request & response can be found including my awkward attempt to get the id value {{item.id}}.To do so I created a on-tap function when a user clicks on one of the cards which then should get the value of the stdId attribute.

<dom-module id="my-students-view">
<template>

<style>
:host {
display: block;
}
</style>

<!-- Iron-Ajax created connection and gets data -->
<iron-ajax
auto
id="requestRepos"
url="http://api.dev/user/"
handle-as="json"
loading="{{isloading}}"
last-response="{{response}}"></iron-ajax>

<!-- dom-repeat iterates the response -->
<template is="dom-repeat" items="[[response.data]]" sort="sortData">
<student-card
id="studentCard"
to="http://localhost:8080/profile-view/{{item.id}}"
picsrc="../../images/anonymous.jpg"
name="{{item.first_name}} {{item.last_name}}"
stdId="{{item.id}}"
on-tap="sendId"></student-card>

</template>
</template>

<script>
Polymer({
is: 'my-students-view',

properties: {
stdId: {
notify: true,
}
},

//Sort the array/data alphabetically
sortData: function(a, b) {
if(a.first_name < b.first_name) return -1;
if(a.first_name > b.first_name) return 1;
return 0;
},

//Try to get the id value of a the student card
sendId: function() {
var idPropertie = this.$$("#studentCard");
var idValue = idPropertie.getAttribute('stdId');
console.log('the id is:' + idValue);
},

});

</script>
</dom-module>

Answer

Rewrite the sendId function:

sendId: function(event) {
  var idValue = event.model.item.id;
  console.log('the id is:' + idValue);
},