d3 js - loading json without a http get

Question

I am learning d3. There are certain ways of loading the data in d3 js. But all of them seem to make a HTTP GET. In my scenario, I already have the json data in a string. How can I use this string instead of making another http request? I tried to look for documentation for this but found none.

This works:

d3.json("/path/flare.json", function(json) {
    //rendering logic here
}

Now, if I have:

//assume this json comes from a server (on SAME DOMAIN)
var myjson = '{"name": "flare","children": [{"name": "analytics","children": [{"name": "cluster","children": [{"name": "MergeEdge", "size": 10 }]}]}]}';

How do I use already computed 'myjson' in d3 & avoid a async call to server? Thanks.

What is it that you want to do with the object? Also, why would you hard-code that as a string instead of as a plain JavaScript object? — Pointy
– Pointy, Commented Jun 7, 2012 at 15:36
@Pointy The server returns it as a model attribute in the response. So I have the string. For eg, the json I have corresponds to the code in mbostock.github.com/d3/ex/bubble.html Thats the logic that goes in there — Ravi
– Ravi, Commented Jun 7, 2012 at 15:41

Luca Rainone · Accepted Answer · 2013-09-18 20:44:40Z

83

Simply replace d3.json call with

json = JSON.parse( myjson );

IE:

var myjson = '{"name": "flare","children": [{"name": "analytics","children": [{"name": "cluster","children": [{"name": "MergeEdge", "size": 10 }]}]}]}';

// d3.json("/path/flare.json", function(json) { #delete this line

    json = JSON.parse( myjson ); //add this line

    //rendering logic here

//} #delete this line

UPDATE 09/2013

Original code has changed. So varname json should be root:

// d3.json("flare.json", function(error, root) { #delete this line

    root = JSON.parse( myjson ); //add this line

    //rendering logic here

//} #delete this line

edited Sep 18, 2013 at 20:44

answered Jun 7, 2012 at 15:34

Luca Rainone

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7 Comments

Ravi Over a year ago

Got that part. Can you let me know how to use this parsed 'json' object to render the graph (without making a GET reqeust) found here mbostock.github.com/d3/ex/bubble.html The example uses d3.json("../data/flare.json", function(json) which makes a http call. Any pointers to docs/examples will help too. Thanks.

Luca Rainone Over a year ago

@Ravi replace line 14 with json = JSON.parse( myjson ); and delete line 33. Try it

Ravi Over a year ago

Tried it. Worked perfectly! Now I see what is happening... Thank you!!

David Mann Over a year ago

Thanks, I had similar situation. Of course obvious now that it works but your guidance was helpful since I am still getting my bearings with d3.

Adrian Over a year ago

wait, how exactly is the variable json being passed to d3 library? Can you explain what is happening here?

|

John Sharp · Accepted Answer · 2013-07-09 15:57:12Z

3

The answer from chumkiu worked great for me but needed a couple of tweaks - in the latest version of the d3 bubble chart, you need to define root rather than json, as in

 root = JSON.parse( myjson );

Alternatively, you could replace "root" with "json" in the rest of the code of course. :-)

For anyone coming to this answer with questions about d3 node-link trees that utilize local data sets, this answer worked great for me - many thanks to the contributors on this page.

answered Jul 9, 2013 at 15:57

John Sharp

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Comments

dardo · Accepted Answer · 2012-06-07 15:49:49Z

2

According to this example:

http://phrogz.net/JS/d3-playground/#StockPrice_HTML

Here they are storing the graph data within the variable $data, and setting it via the .data($data) function.

I'd apply this method to whatever graph you are using.

answered Jun 7, 2012 at 15:49

dardo

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1 Comment

Adrian Over a year ago

This might work; They have a similar example here: github.com/mbostock/d3/wiki/Selections#wiki-data

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