NodeJs JSON parsing issue

Question

I have a .json file where i have people's names stored. I'm reading the content from this file using the file system from Node Manager and then I'm trying to convert this json to string and parsing it to JS object. After parsing it to JS object i get as type string instead of object. Here is the example json file :

{
"21154535154122752": {
    "username": "Stanislav",
    "discriminator": "0001",
    "id": "21154535154122752",
    "avatar": "043bc3d9f7c2655ea2e3bf029b19fa5f",
    "shared_servers": [
        "Reactiflux",
        "Discord Testers",
        "Official Fortnite",
        "Discord API"
    ]
    }
}

and here is the code for processing the data:

const string_data = JSON.stringify(fs.readFileSync('data/users.json', 'utf8'));
const data = JSON.parse(string_data);
console.log(typeof(data)); // <-- this line here shows the type of data as string
const results_array   = Object.values(data);

where fs is the file system package from npm.

Possible duplicate of Using Node.JS, how do I read a JSON object into (server) memory? — Heretic Monkey
– Heretic Monkey, Commented Apr 8, 2018 at 17:43
I have tried all those methods but i still get the type string for unknown reason. — Peter Stoyanov
– Peter Stoyanov, Commented Apr 8, 2018 at 17:45
I would recommend to do a console.log() after each statement and see its format, and so its easier to understand where and whats going wrong. also assign fs.readFileSync to a variable and then reuse it. its more readable IMO. — AmirHossein Rd
– AmirHossein Rd, Commented Apr 8, 2018 at 17:47

S4beR · Accepted Answer · 2018-04-08 18:12:38Z

1

don't use JSON.stringify as it is further changing the string representation of JSON object. An example of what is happening is below

Imagine if you have a data in your file as shown below

{
   "key": "value"
}

When you read the file (using readFileSync) and apply JSON.stringify, it is converted to a new string as shown below. You can notice that the double quotes are now escaped

"{\"key\": \"value\"}"

Now when you will parse it using JSON.parse then instead of getting the desired object, you are going to get back the same string you read from the file.

You are basically first performing and then undoing the stringify operation

edited Apr 8, 2018 at 18:12

answered Apr 8, 2018 at 18:05

S4beR

1,8471 gold badge18 silver badges33 bronze badges

Sign up to request clarification or add additional context in comments.

7 Comments

Peter Stoyanov Over a year ago

I get it now but when i use the other way around i get this error: undefined: 1 '{' SyntaxError: Unexpected token in JSON at position 0

S4beR Over a year ago

can you print the string you received from readFileSync using console.info and check if that's correct?

Peter Stoyanov Over a year ago

Yes everything looks fine. But cant get rid of this error.

Peter Stoyanov Over a year ago

When i print the string in the console i dont receive with the quotes at the ends is that something that i should worry about @S4beR ?

S4beR Over a year ago

i assume you are seeing something like {"key": "value"}? This representation is fine

|

AmirHossein Rd · Accepted Answer · 2018-04-08 17:58:52Z

1

Okay so fs.readFileSync returns a string so you dont need to use stringify

var fs = require('fs');
var read = fs.readFileSync('data/users.json', 'utf8');
console.log(read);
console.log(typeof(read));
const data = JSON.parse(read);
console.log(typeof(data));

You will see it returns an object

answered Apr 8, 2018 at 17:58

AmirHossein Rd

2534 silver badges15 bronze badges

3 Comments

Peter Stoyanov Over a year ago

I dont know but i get the error undefined: 1 '{' SyntaxError: Unexpected token in JSON at position 0

AmirHossein Rd Over a year ago

just to make sure, you have a folder called data and inside has users.json right?

Peter Stoyanov Over a year ago

it stays with the same problem @AmirHosseinRd

Honza Hejzl · Accepted Answer · 2018-04-08 18:12:31Z

0

This works for me:

const data = JSON.parse(fs.readFileSync('data/users.json', 'utf8'));
console.log(typeof(data)); // <-- this line here shows the type of data as OBJECT
const results_array   = Object.values(data);

answered Apr 8, 2018 at 18:12

Honza Hejzl

8848 silver badges25 bronze badges

1 Comment

Peter Stoyanov Over a year ago

i really dont know what I'm doing wrong maybe it is from the json that is not constructed well.

Collectives™ on Stack Overflow

NodeJs JSON parsing issue

3 Answers 3

7 Comments

3 Comments

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

7 Comments

3 Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related