NodeJs read JSON file

Question

I am tying to read a json file using NodeJs

my code is pretty basic,

  var obj = require("./sample.json");
  console.log(obj[0]);

The sample.json file contains a stringified JSON like this,

"[{\"sample\":\"good\",\"val\":76159}]"

However the console.log output is '[' not the first element in the variable. I have tried opening the file in the long way like this as well.

var obj;
fs.readFile('sample.json', 'utf8', function (err, data) {
  if (err) throw err;
  obj = JSON.parse(data);
  console.log(obj[0]);
});

But here also the output is '[' why is the json file not properly parsed? How can I fix it?

Thanks in advance.

jsfiddle.net/xgfgmx08 if data is what you said, it should work. double check what's inside data — BeNdErR
– BeNdErR, Commented Jul 12, 2016 at 10:00
@BeNdErR can you try code where it opens a json in a local computer, I guess the problem is the way we open the file because the example works fine, is there an issue in the way we open the json file? — rksh
– rksh, Commented Jul 12, 2016 at 10:06
@rksh try to console.log(data) as soon as you read it. What's the output? — BeNdErR
– BeNdErR, Commented Jul 12, 2016 at 10:08
Have you made: var fs = require('fs'); and tested that you get data once you read the file as commented by @BeNdErR ? — Yosvel Quintero
– Yosvel Quintero, Commented Jul 12, 2016 at 10:24

t.niese · Accepted Answer · 2016-07-12 11:09:40Z

4

Your file should contain:

[{"sample":"good","val":76159}]

If it contains

"[{\"sample\":\"good\",\"val\":76159}]"

Then it is encoded twice. It is still valid JSON because it is a string, but this JSON does not represent the JavaScript Object:

[{
  sample:"good",
  val:76159
}]

But a string with the content [{"sample":"good","val":76159}].

If you add a second parse (the first one is implicitly done by the require):

var obj = JSON.parse(require("./sample.json"));
console.log(obj[0]);

then you will see that the the correct information is logged.
So your initial problem is that you stored the value the wrong way in ./sample.json.

answered Jul 12, 2016 at 10:59

t.niese

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Comments

Young · Accepted Answer · 2016-07-12 10:42:28Z

4

[info.json]

[{
    "name" : "Young",
    "age" : 100,
    "skill" : "js"
}]

[main.js]

var jsonObj = require('./info.json');
console.log(jsonObj[0]);

[result]

{ name: 'Young', age: 100, skill: 'js' }

answered Jul 12, 2016 at 10:36

Young

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