Unable to load json file in html using d3.js

Question

I want to load data from a json file in an HTML file and use D3 to visualize it. I am able to view the data in the browser if the file is loaded on its own. The file is also received correctly verified by the 200 status. But the contents of the file are interpreted as null.

Here are the contents of the json file -

[{"totdistance":[[1987,20926761],[1988,81974990],[1989,93470285],[1990,116938068],[1991,128179520],[1992,123889922],[1993,113169123],[1994,119145135],[1995,132070386],[1996,145689003],[1997,158173093],[1998,164900616],[1999,180094162],[2000,191005263],[2001,186583998],[2002,185726579],[2003,189239126],[2004,203622782],[2005,200373825]],"routes":[[1987,45399],[1988,180871],[1989,195588],[1990,216314],[1991,219896],[1992,199066],[1993,176756],[1994,177851],[1995,194508],[1996,203001],[1997,206304],[1998,203071],[1999,209496],[2000,219160],[2001,209979],[2002,196111],[2003,189519],[2004,195939],[2005,197853]],"code":"HP","name":"HP","avgdelay":[[1987,16],[1988,8],[1989,11],[1990,12],[1991,12],[1992,7],[1993,11],[1994,15],[1995,17],[1996,23],[1997,17],[1998,29],[1999,25],[2000,28],[2001,18],[2002,9],[2003,13],[2004,25],[2005,18]]}]

Here is the code that tries to load the file and read its contents -

d3.json("flights.json", function(flights) {

But I get error on the console that flights is null.

I have tried running this code on a webserver using IE, Firefox and Chrome. But no solution.

I am using this as a starting point - https://github.com/mbostock/bost.ocks.org/blob/gh-pages/mike/nations/index.html

Here is the error - Uncaught TypeError: Cannot call method 'map' of null

The json is valid as per http://jsonlint.com/

Thanks for any help to fix this issue.

Answer 1

I have switched to version 2.8 and it is working fine. One thing I noticed was that I was calling one variable as avgdelay and that was an issue. Once I renamed the variable to another one, d3 had no problems. I think it is kind of weird. But as of now, it has fixed the problem I was facing. I am closing the question.

Answer 2

according to this, the correct syntax of d3.json is

d3.json('URL', function(error, json) {

so it appears you might be trying to access the error argument, which if there is no error, could be null.