How can i fix json.decoder.JSONDecodeError ?

[snippsat]

You don't show content of data.json.
Here is my test with a random validated json file.
data.json before:

{
    "devDependencies": {
        "eslint": "^6.8.0",
        "eslint-config-prettier": "^6.10.1",
        "prettier": "^2.0.2"
    },
    "scripts": {
        "eslint": "eslint . --fix",
        "eslint:check": "eslint .",
        "lint": "npm run prettier && npm run eslint"
    },
    "dependencies": {
        "@jsxtools/resize-observer": "^1.0.4"
    }
}

import json
from pprint import pprint
 
def write_json(new_date, filename='data.json'):
    with open(filename, 'r+') as file:
        file_data = json.load(file)
        #print(file_data)
 
        file_data["scripts"].update(new_date)
        #pprint(file_data)
        file.seek(0)
        json.dump(file_data, file, indent=4)
 
if __name__ == '__main__':
    y = {
        "emp_name": "Nikhil",
        "email": "[email protected]",
        "job_profile": "Full Time",
    }
    write_json(y)

data.json after:

Output:
{
    "devDependencies": {
        "eslint": "^6.8.0",
        "eslint-config-prettier": "^6.10.1",
        "prettier": "^2.0.2"
    },
    "scripts": {
        "eslint": "eslint . --fix",
        "eslint:check": "eslint .",
        "lint": "npm run prettier && npm run eslint",
        "emp_name": "Nikhil",
        "email": "[email protected]",
        "job_profile": "Full Time"
    },
    "dependencies": {
        "@jsxtools/resize-observer": "^1.0.4"
    }
}