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Get json data structure with nodejs

This is a problem that is so hard for me to find using just keywords -- I've scrolled pages after pages and all the hits are on getting data from json structure, instead of getting data structure from json.
If you don't know what goal I'm trying to achieve, here are tools to get data structure from json to Go:
https://mholt.github.io/json-to-go/
This tool instantly converts JSON into a Go type definition
https://json2struct.mervine.net/
Convert JSON in to a useful struct.
https://transform.tools/json-to-go
online playground to convert JSON to Go Struct
For one specific application, I'm getting data with all kinds of slightly different json data structures, which makes my data extraction failing all the times. I need to compare those data structure-wise, as each individual json data are surely different.

It looks like you're struggling to find what you want because vanilla JavaScript doesn't have the type concepts you're trying to use.
You probably want to generate a json schema or a typescript interface, and searching "JSON to schema npm" will get you more useful results.
One such example is to-json-schema
import toJsonSchema from 'to-json-schema';
toJsonSchema({ "foo": "bar", "x": [1, 2] });
/* returns
{
"type": "object",
"properties": {
"foo": {
"type": "string"
},
"x": {
"type": "array",
"items": {
"type": "integer"
}
}
}
}
*/
For more specific answers you'd need to provide some minimal sample of input and output, e.g. what would you expect from { "foo": "bar", "x": [1, 2] }

update nested value in javascript array

This is an odd question, but I hope someone can help me out.
I have a JS object (it's actually JSON string which is then converted back and object.).
{
"legs": [{
"pods": [{
"11": {
"id": 6,
"name": "tesla",
"text": "tesla model2",
"battery": "60"
},
"21": {
"id": 9,
"name": "porsche",
"text": "porsche electric",
"battery": "100"
}
}]
}]
}
So in my javascript I'll call a specific item... say, legs.pods[11].name
I pass that into a function like editThisField(legs.pods[11].name);
On that function editThisField(whichDataElement){.....} I'll show a modal box where the user can provide new text for the name value... what I would like is to have the whichDataElement updated to the new text such that which ever object variable I pass into that field, is updated in the legs object... I'm not sure if I'm explaining this very well, but I can't think where to start looking at a good approach to this.
Essentially I'm making a text area where I paste in the JSON, and the system allows me to edit the JSON object via modal popups. So the modal appears and dynamically shows a form based on the data in the specific sub object. When you fill in the form, the original JSON is updated... thoughts?
Not really working as I need... Maybe this helps clarify:
var mything = {
subthing: {
thisthing: "here"
}
}
var edit = mything.subthing.thisthing;
edit = "Changed";
console.log(mything); // then the listthing value should be changed.

It sounds like you're on the right track. If you pass in an object to your editThisField function you can change it's contents, but in your example you are passing in a primitive (which won't work as it's passed by value).
Another option... since you're loading a modal I assume you know what attribute you want to change so you can just specify the object keys or array indices dynamically. See example here https://jsfiddle.net/jroden1f/. Note, I changed your data model slightly as I wasn't sure why you had legs and pods as arrays and it made the example easier if I just made them objects.

Converting data table to suitable javascript object (C#)

Short question:
Given table based data (such as SQL results), what is the most accepted method of converting this into a specific json string / js objectstring with C#?
Scenario:
I have a web page using d3.js to general graphical reports. For the data, I call an API which executes a stored procedure and returns the result set. I need a way of converting that data into a suitable json object which can easily be processed within my d3 report.
Example:
With the following table being returned by my stored procedure
What would be the most suitable kind of object to convert this data into for use with javascript / d3, and how would one go about achieving that?
What I've tried:
Since my API is written in C#, I've tried using the JsonConvert.SerializeObject method, as below.
DataTable dt = new DataTable();
using (SqlDataAdapter sql = new SqlDataAdapter(getData))
{
sql.Fill(dt);
}
returnStr = JsonConvert.SerializeObject(dt);
Which produces a simple array, one item per row of data, for example:
[
{
"Group": "Group01", "TrueFalse": 1, "SubGroup": "SubGroup01", "Owner": "ME"
},
{
"Group": "Group01", "TrueFalse": 1, "SubGroup": "SubGroup02", "Owner": "ME"
},
{
"Group": "Group01", "TrueFalse": 0, "SubGroup": "SubGroup02", "Owner": "You"
},
{
"Group": "Group01", "TrueFalse": 1, "SubGroup": "SubGroup03, "Owner": "You"
},
{
"Group": "Group02", "TrueFalse": 0, "SubGroup": "SubGroup01", "Owner": "Someone"
},
// etc...
]
While its quite possible to work with this, I don't know if it's the best way of going about doing so, or whether we can create an object that's more suitable. If you can give any pointers on best practises, and possible examples, that would be great.

This is more of preference issue and perhaps consistency in your data model. What you have there is perhaps the preferred method as it is easy to iterate through while knowing the object structure in the array. Another way of doing it, and is harder to understand if you are an incoming developer, is to have an array for each column in the table and iterating by the index of the array to get the values. This would require more code and is less readable. So rather than indexing each field for each iteration through the array, you simply have objects that have a consistent structure, even if a field in the object is empty, which leads to another issue with the array-per-column approach: you would have to be absolutely sure that a field cannot be empty. Otherwise, your indexing counts will not be consistent.
Long story short, what you have there is semantically the most appropriate. Table columns equate to fields in your object, and the JSON object equates to a row in your table.I hope this makes sense to you and helps out.

Structure of the JSON flare input for D3.js Treemap Visualization

I am currently working with the Treemap visualization of D3.js and was hoping to understand how the flare.json used in the example has been organized. Does the format of the json input file need to be in the exact same structure as used in the example. I have an input file from a web crawler with a list of URLs and their respective parent URLs. I tried using something like the following but it won't work and am not sure if it's just the structure that's different or something else.
listURLs.json:
{
"name": "flare",
"children": [
{"children":"http:\/\/a.wholelottanothing.org","name":"http:\/\/buzz.blogger.com"},
{"children":"http:\/\/www.bitworking.org","name":"http:\/\/buzz.blogger.com"},
{"children":"http:\/\/blog.computationalcomplexity.org","name":"http:\/\/buzz.blogger.com"},
{"children":"http:\/\/www.blogactionday.org","name":"http:\/\/buzz.blogger.com"},
{"children":"http:\/\/www.wikipaintings.org","name":"http:\/\/littlegreeniguana.blogspot.com"}
]
}
I know this looks very different from the flare.json used in the example but can this work? Also, the input that I am using doesn't include the 'size' parameter which is also probably why the output is blank. How do I use the size here? Can it be dynamically adjusted later in the code? Any help will be most appreciated, I am a D3 novie!

The hierarchical data format expected by tree, pack and other D3 hierarchical layouts is expecting "children" to be an array of objects, and traverses that hierarchical data in preparation for formatting your objects for display using layouts. So, you don't want to use "children" to store a single link, instead, you want it to store an array of objects formatted just like the parent object (even if there is only one thing in that array). It's a bit hard to grasp what you're trying to display in your dataset, but my guess is all those websites are under buzz.blogger.com, except the last one, in which case properly formatted hierarchical data would look like this (Note that everything is nested in a root node, which you can name whatever you want):
{
"name": "root node",
"children": [
{"name":"http:\/\/buzz.blogger.com", "children": [
{"name": "http:\/\/www.bitworking.org"},
{"name": "http:\/\/blog.computationalcomplexity.org"},
{"name": "http:\/\/www.blogactionday.org"}
]
},
{"name":"http:\/\/littlegreeniguana.blogspot.com", "children": [
{"name": "http:\/\/www.wikipaintings.org"}
]
}
]
}

Querying/Searching for Values within JSON

For a web site I'm creating, I have to create a quote based on data provided as a JSON string from the server. I've been looking through this site (and various others) but still am unsure on the best way to query/search the data.
For example, I need to get the Area Name from the Area ID. I need to get the maximum age for an area and also the price for a given minimum/maximum age.
I also want to get an array of prices.
Is it best to create a Javascript object from the string using the eval method? Or should I be using jQuery.
Thanks for your help.
({"SkiPass":[{"Id":1,"Area":"Chamonix","Rates":[{"Id":1,"AgeMin":0,"AgeMax":2,"Price":2.5},{"Id":2,"AgeMin":3,"AgeMax":17,"Price":5.0},{"Id":3,"AgeMin":18,"AgeMax":30,"Price":6.2},{"Id":4,"AgeMin":31,"AgeMax":59,"Price":7.4}]},
{"Id":2,"Area":"Megeve","Rates":[{"Id":1,"AgeMin":0,"AgeMax":2,"Price":1},{"Id":2,"AgeMin":3,"AgeMax":17,"Price":2.0},{"Id":3,"AgeMin":18,"AgeMax":30,"Price":2.2},{"Id":4,"AgeMin":31,"AgeMax":59,"Price":4.4}]},
{"Id":3,"Area":"Verbier","Rates":[{"Id":1,"AgeMin":0,"AgeMax":2,"Price":1.5},{"Id":2,"AgeMin":3,"AgeMax":17,"Price":3.0},{"Id":3,"AgeMin":18,"AgeMax":30,"Price":4.2},{"Id":4,"AgeMin":31,"AgeMax":59,"Price":5.4}]}]})

Create a JavaScript object from the string, most definitely, but do it with legitimate JSON parsing facilities and not "eval()". You could use jQuery, but there are other solutions, such as the JSON tools available from json.org, which are small and simple.
Once it's a JavaScript object, well then your needs should guide you as to whether some query solution is necessary, or instead that it's just a simple matter of programming.

I think the best method is jLinq: http://hugoware.net/Projects/jLinq it's like doing a SQL query on JSON.
It doesn't needs jQuery.
I use it, and it's great.

Create the object from the JSON string using JSON.parse() or jQuery.parseJSON() if you are already using jQuery -- or just pass it as from the server side as JSON.
You can then iterate through the object to find the record you want. Or, you can use build your objects so that you can naturally grab data from them.

FloatLeft - as Dan points out, your task would be much easier if you could use XPath but there is no need to re-write your data in XML format. With DefiantJS (http://defiantjs.com) you can now query JSON structure with XPath expressions.
DefiantJS extends the global object JSON with the method "search", which enables XPath queries and returns an array with the matches (empty array if no matches were found). The returned array is equipped with aggregate functions as well; one of these "sortDesc".
Check out this working fiddle;
http://jsfiddle.net/hbi99/H3PR3/
var data = {
"SkiPass": [
...
{
"Id": 3,
"Area": "Verbier",
"Rates": [
{ "Id": 1, "AgeMin": 0, "AgeMax": 2, "Price": 1.5 },
{ "Id": 2, "AgeMin": 3, "AgeMax": 17, "Price": 3 },
{ "Id": 3, "AgeMin": 18, "AgeMax": 30, "Price": 4.2 },
{ "Id": 4, "AgeMin": 31, "AgeMax": 59, "Price": 5.4 }
]
}
]
},
res1 = JSON.search( data, '//SkiPass[Id=3]/Area' ),
res2 = JSON.search( data, '//*[Area and Id=3]/Rates' )
.sortDesc('AgeMax'); // <-- sorting descending by the value of "AgeMax"
document.getElementById('name').innerHTML = res1;
document.getElementById('max_age').innerHTML = res2[0].AgeMax;
document.getElementById('price').innerHTML = res2[0].Price;