I am trying to write a JSON object to a JSON file. The code executes without errors, but instead of the content of the object been written, all that gets written into the JSON file is:
[object Object]
This is the code that actually does the writing:
fs.writeFileSync('../data/phraseFreqs.json', output)
'output' is a JSON object, and the file already exists. Please let me know if more information is required.
You need to stringify the object.
fs.writeFileSync('../data/phraseFreqs.json', JSON.stringify(output));
fs.writeFileSync('../data/phraseFreqs.json', JSON.stringify(output, null, 2)); More: developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/…I don't think you should use the synchronous approach, asynchronously writing data to a file is better also stringify the output if it's an object.
Note: If output is a string, then specify the encoding and remember the flag options as well.:
const fs = require('fs');
const content = JSON.stringify(output);
fs.writeFile('/tmp/phraseFreqs.json', content, 'utf8', function (err) {
if (err) {
return console.log(err);
}
console.log("The file was saved!");
});
Added Synchronous method of writing data to a file, but please consider your use case. Asynchronous vs synchronous execution, what does it really mean?
const fs = require('fs');
const content = JSON.stringify(output);
fs.writeFileSync('/tmp/phraseFreqs.json', content);
Make the json human readable by passing a third argument to stringify:
fs.writeFileSync('../data/phraseFreqs.json', JSON.stringify(output, null, 4));
When sending data to a web server, the data has to be a string (here). You can convert a JavaScript object into a string with JSON.stringify().
Here is a working example:
var fs = require('fs');
var originalNote = {
title: 'Meeting',
description: 'Meeting John Doe at 10:30 am'
};
var originalNoteString = JSON.stringify(originalNote);
fs.writeFileSync('notes.json', originalNoteString);
var noteString = fs.readFileSync('notes.json');
var note = JSON.parse(noteString);
console.log(`TITLE: ${note.title} DESCRIPTION: ${note.description}`);
Hope it could help.
Here's a variation, using the version of fs that uses promises:
const fs = require('fs');
await fs.promises.writeFile('../data/phraseFreqs.json', JSON.stringify(output)); // UTF-8 is default
