How do I update the data saved in a JSON file using JavaScript?

Question

for example: If i have a JSON file called 'person.json', looking like:

{
  "Person": [
    {
      "Firstname": "John",
      "Lastname": "Doe"
    }
  ]
}

and I would like to append as new data set the name 'John Smith'. How could I do this using JavaScript?

EDIT: Now I tried to use 'fs.readFile()' to read my JSON file. The application I develop is a hybrid app using cordova. If i use 'fs.readFile()' i get the error 'Uncaught ReferenceError: fs is not defined'. I tried to fix this problem by adding the line 'var fs = Npm.require('fs');'. But this causes also an error: 'Uncaught ReferenceError: Npm is not defined'

Is this error caused because npm is not available on a smartphone? And how can i fix this problem?

Possible duplicate of [How to write data to a JSON file using Javascript](https://stackoverflow.com/questions/32546100/how-to-write-data-to-a-json-file-using-javascript) — cнŝdk, May 30 '17 at 14:19
Are you trying to do it server side, am I right? If it's a browser app, you'll need a back-end that handles the JSON file, and then call it from your javascript running in the browser. The good news is that you can do the back-end using javascript to, see [node.js](https://nodejs.org/) — Rômulo M. Farias, May 30 '17 at 14:25

score 3 · Accepted Answer · answered May 30 '17 at 14:19

3

You can simply use JSON.parse(data) to parse the JSON string into an object. Then when you're done, use JSON.stringify(object) to convert it into a JSON string.

You can write and read files with fs link.

answered May 30 '17 at 14:19

Tvde1

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How can I do this without using Node.js because I am doing my backend with the Python Django? – Mayur Gupta Jul 15 '21 at 03:11

How do I update the data saved in a JSON file using JavaScript?

1 Answers1

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