Javascript how to parse JSON array
JavascriptJsonExtjsJavascript Problem Overview
I'm using Sencha Touch (ExtJS) to get a JSON message from the server. The message I receive is this one :
{
"success": true,
"counters": [
{
"counter_name": "dsd",
"counter_type": "sds",
"counter_unit": "sds"
},
{
"counter_name": "gdg",
"counter_type": "dfd",
"counter_unit": "ds"
},
{
"counter_name": "sdsData",
"counter_type": "sds",
"counter_unit": " dd "
},
{
"counter_name": "Stoc final",
"counter_type": "number ",
"counter_unit": "litri "
},
{
"counter_name": "Consum GPL",
"counter_type": "number ",
"counter_unit": "litri "
},
{
"counter_name": "sdg",
"counter_type": "dfg",
"counter_unit": "gfgd"
},
{
"counter_name": "dfgd",
"counter_type": "fgf",
"counter_unit": "liggtggggri "
},
{
"counter_name": "fgd",
"counter_type": "dfg",
"counter_unit": "kwfgf "
},
{
"counter_name": "dfg",
"counter_type": "dfg",
"counter_unit": "dg"
},
{
"counter_name": "gd",
"counter_type": "dfg",
"counter_unit": "dfg"
}
]
}
My problem is that I can't parse this JSON object so that i can use each of the counter objects.
I'm trying to acomplish that like this :
var jsonData = Ext.util.JSON.decode(myMessage);
for (var counter in jsonData.counters) {
console.log(counter.counter_name);
}
What am i doing wrong ? Thank you!
Javascript Solutions
Solution 1 - Javascript
Javascript has a built in JSON parse for strings, which I think is what you have:
var myObject = JSON.parse("my json string");
to use this with your example would be:
var jsonData = JSON.parse(myMessage);
for (var i = 0; i < jsonData.counters.length; i++) {
var counter = jsonData.counters[i];
console.log(counter.counter_name);
}
EDIT: There is a mistake in your use of for loop (I missed this on my first read, credit to @Evert for the spot). using a for-in loop will set the var to be the property name of the current loop, not the actual data. See my updated loop above for correct usage
IMPORTANT: the JSON.parse method wont work in old old browsers - so if you plan to make your website available through some sort of time bending internet connection, this could be a problem! If you really are interested though, here is a support chart (which ticks all my boxes).
Solution 2 - Javascript
In a for-in-loop the running variable holds the property name, not the property value.
for (var counter in jsonData.counters) {
console.log(jsonData.counters[counter].counter_name);
}
But as counters is an Array, you have to use a normal for-loop:
for (var i=0; i<jsonData.counters.length; i++) {
var counter = jsonData.counters[i];
console.log(counter.counter_name);
}
Solution 3 - Javascript
This is my answer:
<!DOCTYPE html>
<html>
<body>
<h2>Create Object from JSON String</h2>
<p>
First Name: <span id="fname"></span><br>
Last Name: <span id="lname"></span><br>
</p>
<script>
var txt =
'{"employees":[' +
'{"firstName":"John","lastName":"Doe" },' +
'{"firstName":"Anna","lastName":"Smith" },' +
'{"firstName":"Peter","lastName":"Jones" }]}';
//var jsonData = eval ("(" + txt + ")");
var jsonData = JSON.parse(txt);
for (var i = 0; i < jsonData.employees.length; i++) {
var counter = jsonData.employees[i];
//console.log(counter.counter_name);
alert(counter.firstName);
}
</script>
</body>
</html>
Solution 4 - Javascript
"Sencha way" for interacting with server data is setting up an Ext.data.Store proxied by a Ext.data.proxy.Proxy (in this case Ext.data.proxy.Ajax) furnished with a Ext.data.reader.Json (for JSON-encoded data, there are other readers available as well). For writing data back to the server there's a Ext.data.writer.Writers of several kinds.
Here's an example of a setup like that:
var store = Ext.create('Ext.data.Store', {
fields: [
'counter_name',
'counter_type',
'counter_unit'
],
proxy: {
type: 'ajax',
url: 'data1.json',
reader: {
type: 'json',
idProperty: 'counter_name',
rootProperty: 'counters'
}
}
});
data1.json in this example (also available in this fiddle) contains your data verbatim. idProperty: 'counter_name' is probably optional in this case but usually points at primary key attribute. rootProperty: 'counters' specifies which property contains array of data items.
With a store setup this way you can re-read data from the server by calling store.load(). You can also wire the store to any Sencha Touch appropriate UI components like grids, lists or forms.
Solution 5 - Javascript
Something more to the point for me..
var jsontext = '{"firstname":"Jesper","surname":"Aaberg","phone":["555-0100","555-0120"]}';
var contact = JSON.parse(jsontext);
document.write(contact.surname + ", " + contact.firstname);
document.write(contact.phone[1]);
// Output:
// Aaberg, Jesper
// 555-0100
> Reference: > https://docs.microsoft.com/en-us/scripting/javascript/reference/json-parse-function-javascript
Solution 6 - Javascript
This works like charm!
So I edited the code as per my requirement. And here are the changes: It will save the id number from the response into the environment variable.
var jsonData = JSON.parse(responseBody);
for (var i = 0; i < jsonData.data.length; i++)
{
var counter = jsonData.data[i];
postman.setEnvironmentVariable("schID", counter.id);
}
Solution 7 - Javascript
The answer with the higher vote has a mistake. when I used it I find out it in line 3 :
var counter = jsonData.counters[i];
I changed it to :
var counter = jsonData[i].counters;
and it worked for me. There is a difference to the other answers in line 3:
var jsonData = JSON.parse(myMessage);
for (var i = 0; i < jsonData.counters.length; i++) {
var counter = jsonData[i].counters;
console.log(counter.counter_name);
}
Solution 8 - Javascript
Just as a heads up...
var data = JSON.parse(responseBody);
has been deprecated.
Postman Learning Center now suggests
var jsonData = pm.response.json();
Solution 9 - Javascript
You should use a datastore and proxy in ExtJs. There are plenty of examples of this, and the JSON reader automatically parses the JSON message into the model you specified.
There is no need to use basic Javascript when using ExtJs, everything is different, you should use the ExtJs ways to get everything right. Read there documentation carefully, it's good.
By the way, these examples also hold for Sencha Touch (especially v2), which is based on the same core functions as ExtJs.
Solution 10 - Javascript
Not sure if my data matched exactly but I had an array of arrays of JSON objects, that got exported from jQuery FormBuilder when using pages.
Hopefully my answer can help anyone who stumbles onto this question looking for an answer to a problem similar to what I had.
The data looked somewhat like this:
var allData =
[ [ { "type":"text", "label":"Text Field" }, { "type":"text", "label":"Text Field" } ],
[ { "type":"text", "label":"Text Field" }, { "type":"text", "label":"Text Field" } ]
]
What I did to parse this was to simply do the following:
JSON.parse("["+allData.toString()+"]")