How To Write and Read JSON texts on single file-CodePudding

I'm receiving events in JSON format via a POST route, I would like to save these events in a file like 'example.json' and be able to query it.

I tried using writeFileSync, but it rewrites the entire file. With the flag {flag: 'a '} I was able to save more than one record, but when I try to require 'example.json', I get an error 'Unexpected token { in JSON'.

Works fine when the file has only one record, but gives the error after the second one.

Code:

const filePath = './example.json';
const fs = require('fs');
const file = require('./example.json');

app.post('/events', (request, response) => {
  response.send(request.body);
  const contentString = JSON.stringify(request.body);
  return fs.writeFileSync(filepath, contentString, {flag: 'a '});
});

example.json that works:

{"type":"call.new","call_id":"71252742562.40019","code":"h9e8j7c0tl0j5eexi07sy6znfd1ponj4","direction":"inbound","our_number":"1130900336","their_number":"11999990000","their_number_type":"mobile","timestamp":"2020-04-01T00:00:00Z"}

example.json (with two records) that stop working:

{"type":"call.new","call_id":"71252742562.40019","code":"h9e8j7c0tl0j5eexi07sy6znfd1ponj4","direction":"inbound","our_number":"1130900336","their_number":"11999990000","their_number_type":"mobile","timestamp":"2020-04-01T00:00:00Z"}{"type":"call.ongoing","call_id":"71252731962.40019","code":"h9e8j7c0tl0j5eexi07sy6znfd1ponj4","direction":"inbound","our_number":"1130900336","their_number":"11999990000","their_number_type":"mobile","timestamp":"2020-04-01T00:00:00Z"}

How can I write this JSON in a readable form? That does not present the error above and it is possible to perform the require.

Could someone help me, please?

CodePudding user response：

Try to read the JSON file, parse it, add new elements to the array and then overwrite the file.

const fs = require("fs");
const path = require("path");

const FILE_PATH = path.join(__dirname, "./elements.json");

const file = fs.readFileSync(FILE_PATH);
const elements = JSON.parse(file);

const newElement = { id: Date.now() };
const updatedElements = [...elements, newElement];

fs.writeFileSync(FILE_PATH, JSON.stringify(updatedElements));

See more here: https://nodejs.org/api/fs.html#fsappendfilesyncpath-data-options