Develop Reference

How can I make this JSON.stringify work properly

I have a small issue to make my arrays into the json I want to. I have made this code:
var arrData = [{label:Test,value:199.12}, {label:Test2,value:1024}]
var data = [];
for (var i = 0; i < arrData.length; i++) {
data.push(JSON.stringify({
label: arrData[i][2],
value: arrData[i][3]
}).replace(/\"/g, "").replace("\\r", ""))
}
It also does the job properly. But I do want it to be in this format:
{ label: 'Food', value: 90 },
I want to have the ' ' on the label data and I want to remove the double "" punctuation mark outside the json. Since my current json looks like this:
"{label:Test,value:199.12}", "{label:Test2,value:1024}",

{ label: 'Food', value: 90 } isn't valid JSON so you cannot create it using JSON.stringify.
It isn't any standard serialisation format (although it is a valid JavaScript literal) so if you want to serialise data to it, you'll need to write a custom serialiser.
You could loop over the properties of the object and append them, the associated values, and whatever quotes and commas your format demands, to a string.

Looping through nesting of objects and arrays with Javascript and underscore

I am trying to access objects that are nested within an array. I start with this JSON object (which was derived from an XML database output):
{"report":
{"date":"15 Apr 2016",
"metrics":
{"metric":
[
{"name":"Bank Angle",
"display_parent_group":"Bankfull",
"display_child_group":"SiteShape",
"tolerance":"0.05",
"visits":
{"visit":
[
{"visit_id":"3047","value": "0.47"},
{"visit_id":"2164","value": "0.55"},
{"visit_id":"1568","value": "0.72"},
{"visit_id":"3431","value": "0.12"},
{"visit_id":"2428","value": "0.44"},
{"visit_id":"1567","value": "0.49"}
]}},
{"name":"Bank Angle SD",
"display_parent_group":"Bankfull",
"display_child_group":"SiteShape",
"tolerance":"0.05",
"visits":
{"visit":
[
{"visit_id":"3047","value": "0.12"},
{"visit_id":"2164","value": "0.05"},
{"visit_id":"1568","value": "0.21"},
{"visit_id":"3431","value": "0.68"},
{"visit_id":"2428","value": "0.22"},
{"visit_id":"1567","value": "0.13"}
]}},
{"name":"Bankfull Area",
"display_parent_group":"Bankfull",
"display_child_group":"SiteSize","tolerance":"0.05",
"visits":
{"visit":
[
{"visit_id":"3047","value": "202"},
{"visit_id":"2164","value": "193"},
{"visit_id":"1568","value": "115"},
{"visit_id":"3431","value": "258"},
{"visit_id":"2428","value": "89"},
{"visit_id":"1567","value": "206"}
]}}
]
}
}
}
I then use underscore to extract a subset of metric objects:
var table_metric = JSONData.report.metrics.metric;
var target_metrics = _.where(table_metric, {
display_parent_group : 'Bankfull', display_child_group: 'SiteShape'
});
This results in an array with two nested objects. Where I'm having a problem is then accessing the array of objects which is nested inside visits.visit. If, for instance, I want to build an array of values associated with the key visit_id, and I try:
function buildVisitIDArray(target_metrics) {
var attrList = [];
for(var i=0; i<target_metrics.length; i++) {
var visit_records = target_metrics[i].visits[1];
console.log(visit_records);
for(visit_record in visit_records) {
attrList.push(_.pluck(visit_record, "visit_id"));
}
}
return attrList
}
I just get an array of undefined results. I've spent hours trying variations on the syntax to get at the nested "visit" objects, but I just can't seem to figure it out.
Any help is much appreciated for this novice!

In your buildVisitIDArray function, you are trying to get target_metrics[i].visits[1] as if it was an array, but it's actually an object, so you should use it this way:
function buildVisitIDArray(target_metrics) {
attrList = [];
for(var i=0; i<target_metrics.length; i++) {
var visit_records = target_metrics[i].visits; // Removed the array call ([1])
console.log(visit_records);
for(visit_record in visit_records) {
attrList.push(_.pluck(visit_records[visit_record], "visit_id"));
}
}
return attrList;
}
Hope it helps :)

You may also have an issue if you're not defining attrList with the var keyword somewhere else in your code.
Building on Andre's answer, you may want to change this line to be:
visit_records = target_metrics[i].visits.visit;
to go one layer deeper, then do a regular array for loop afterward.

How can i navigate through the json?

I have some JSON which I have in a object but I can seem to return the values a sample of the json is as follows.
{
"rootLayout":"main",
"layoutDescriptions":[
{
"id":"main",
"container" : {
"type":"Tabs",
"content":[
{
"type":"Panel",
"label":"Simple Address",
"layout":"SimpleForm",
"comment":"This form is simple name value pairs",
"content":[
{ "type":"label", "constraint":"newline", "text":"Org Name" },
{ "type":"text", "property":"propOne" },
{ "type":"label", "constraint":"newline", "text":"Address" },
{ "type":"text", "property":"addrLine1" },
{ "type":"text", "property":"addrLine2" },
{ "type":"text", "property":"addrLine3" },
{ "type":"label", "constraint":"newline", "text":"Postcode" },
{ "type":"text", "property":"postcode" }
]
},
I am trying to return the rootLayout using
obj[0].rootLayout.id
This doesn't work also I am wondering how to access the content elements.
I am new to json and I have been thrown in the deep end I think. I cannot find any good reading on the internet can anyone recommend some.
Thanks.

Some explanation because you don't seem to understand JSON
It's not as complicated as one may think. It actually represents javascript objects as if they'd be written by code.
So if you have JSON written as:
{
id : 100,
name: "Yeah baby"
}
This means that your object has two properties: id and name. The first one is numeric and the second one is string.
In your example you can see that your object has two properties: rootLayout and layoutDescriptions. The first one jsonObj.rootLayout is string and will return "main" and the second one is an array:
layoutDescriptions: [ {...}, {...},... ]
Apparently an array of objects because array elements are enclosed in curly braces. This particular array element object that you provided in your example has its own properties just like I've explained for the top level object: id (string), container (another object because it's again enclosed in curlies) etc...
I hope you understand JSON notation a bit more.
So let's go to your question then
You can get to id by accessing it via:
jsonObj.layoutDescriptions[0].id
and further getting to your content objects:
var contentObjects = jsonObj.layoutDescriptions[0].container.content[0].content;
for(var i = 0; i < contentObjects.length, i++)
{
// assign this inner object to a variable for simpler property access
var contObj = contentObjects[i];
// do with this object whatever you need to and access properties as
// contObj.type
// contObj.property
// contObj.text
// contObj.constraint
}
Mind that this will only enumerate first content object's content objects... If this makes sense... Well look at your JSON object and you'll see that you have nested content array of objects.

The object is an object, not an array, and it doesn't have a property called 0.
To get rootLayout:
obj.rootLayout
However, rootLayout is a string, not an object. It doesn't have an id. The first item in the layoutDescriptions array does.
obj.layoutDescriptions[0].id

Are you trying to get one of layoutDescriptions with id equals to obj.rootLayout?
var targetLayout = {};
for(var i = 0; i < obj.layoutDescriptions.length; i++) {
if(obj.layoutDescriptions[i].id == obj.rootLayout) {
targetLayout = obj.layoutDescriptions[i]; break;
}
}
console.log(targetLayout);

Javascript [Object object] error in for loop while appending string

I am a novice trying to deserialize my result from an onSuccess function as :
"onResultHttpService": function (result, properties) {
var json_str = Sys.Serialization.JavaScriptSerializer.deserialize(result);
var data = [];
var categoryField = properties.PodAttributes.categoryField;
var valueField = properties.PodAttributes.valueField;
for (var i in json_str) {
var serie = new Array(json_str[i] + '.' + categoryField, json_str[i] + '.' + valueField);
data.push(serie);
}
The JSON in result looks like this:
[
{
"Text": "INDIRECT GOODS AND SERVICES",
"Spend": 577946097.51
},
{
"Text": "LOGISTICS",
"Spend": 242563225.05
}
]
As you can see i am appending the string in for loop..The reason i am doing is because the property names keep on changing therefore i cannot just write it as
var serie = new Array(json_str[i].propName, json_str[i].propValue);
I need to pass the data (array type) to bind a highchart columnchart. But the when i check the var serie it shows as
serie[0] = [object Object].Text
serie[1] = [object Object].Spend
Why do i not get the actual content getting populated inside the array?

You're getting that because json_str[i] is an object, and that's what happens when you coerce an object into a string (unless the object implements toString in a useful way, which this one clearly doesn't). You haven't shown the JSON you're deserializing...
Now that you've posted the JSON, we can see that it's an array containing two objects, each of which has a Text and Spend property. So in your loop, json_str[i].Text will refer to the Text property. If you want to retrieve that property using the name in categoryField, you can do that via json_str[i][categoryField].
I don't know what you want to end up with in serie, but if you want it to be a two-slot array where the first contains the value of the category field and the second contains the value of the spend field, then
var serie = [json_str[i][categoryField], json_str[i][valueField]];
(There's almost never a reason to use new Array, just use array literals — [...] — instead.)

How do i reverse JSON in JavaScript?

[
{"task":"test","created":"/Date(1291676980607)/"},
{"task":"One More Big Test","created":"/Date(1291677246057)/"},
{"task":"New Task","created":"/Date(1291747764564)/"}
]
I looked on here, and someone had the same sort of question, but the "checked" correct answer was that it will be different on IE if the item is deleted, which would be fine. My issue is, those items above are stored, but when i go and grab them, iterate, and return, the items are reversed and the created is at the 0 index and task is at 1. Also, i need to return this as JSON.
Here is my basic JS (value == an int the user is passing in):
outputJSON = {};
for(x in json[value]){
outputJSON[x] = _objectRevival(json[value][x]);
}
return outputJSON;
That returns:
created: Mon Dec 06 2010 15:09:40 GMT-0800 (Pacific Standard Time)
task: "test"

The order of the properties of an object is undefined. It is not possible to force them in a specified order. If you need them in a specific order, you can build this structure reliably using arrays:
var values = [
[["task", "test"], ["created", "/Date(1291676980607)/"]],
[["task", "One More Big Test"], ["created", "/Date(1291677246057)/"]],
[["task", "New Task"], ["created", "/Date(1291747764564)/"]]
];
Then you can iterate over your structure like this:
for (var i = 0; i < values.length; i++) {
for (var k = 0; k < values[i]; k++) {
// values[i][k][0] contains the label (index 0)
// values[i][k][1] contains the value (index 1)
}
}

To enforce a particular order for your output just replace json[value] in your for loop with an array of the object properties in the order you want to display them, in your case ["task", "created"].

The problem is that javascript objects don't store their properties in a specific order. Arrays on the other do (hence why you can get something consistent from json[0], json[1], json[2]).
If your objects will always have "task" and "created", then you can get at them in any order you want.
json[value]["task"]
and
json[value]["created"]
Update:
This should work with your existing code.
Before sending the json object:
var before = [
{"task":"test","created":"/Date(1291676980607)/"},
{"task":"One More Big Test","created":"/Date(1291677246057)/"},
{"task":"New Task","created":"/Date(1291747764564)/"}
];
var order = [];
for (var name in before[0]) {
order.push(name); // puts "task", then "created" into order (for this example)
}
Then send your json off to the server. Later when you get the data back from the server:
var outputJSON = {};
for (var x in order) {
if (order.hasOwnProperty(x)) {
outputJSON[order[x]] = _objectRevival(json[value][order[x]]); // I'm not sure what _objectRevival is...do you need it?
}
}
return outputJSON;

var items = ["bag", "book", "pen", "car"];
items.reverse();
This will result in the following output:
car , pen, book, bag
Even if you have JSON array it will reverse.