Write / add data in JSON file using Node.js

If this JSON file won’t become too big over time, you should try:

1. Create a JavaScript object with the table array in itvar obj = { table: [] };
2. Add some data to it, for example:obj.table.push({id: 1, square:2});
3. Convert it from an object to a string with JSON.stringifyvar json = JSON.stringify(obj);
4. Use fs to write the file to diskvar fs = require('fs'); fs.writeFile('myjsonfile.json', json, 'utf8', callback);
5. If you want to append it, read the JSON file and convert it back to an objectfs.readFile('myjsonfile.json', 'utf8', function readFileCallback(err, data){ if (err){ console.log(err); } else { obj = JSON.parse(data); //now it an object obj.table.push({id: 2, square:3}); //add some data json = JSON.stringify(obj); //convert it back to json fs.writeFile('myjsonfile.json', json, 'utf8', callback); // write it back }});

This will work for data that is up to 100 MB effectively. Over this limit, you should use a database engine.

UPDATE:

Create a function which returns the current date (year+month+day) as a string. Create the file named this string + .json. the fs module has a function which can check for file existence named fs.stat(path, callback). With this, you can check if the file exists. If it exists, use the read function if it’s not, use the create function. Use the date string as the path cuz the file will be named as the today date + .json. the callback will contain a stats object which will be null if the file does not exist.