My tool appends little json blocks with comma at their end into a txt file which initially has [
as the first character, in order to create a whole JSON format text file, like below,
{data: text1},
and txt file seems like at the end of the day,
[{data: text1},{data: text2},{data: text3},
So I have to remove last comma at the end of the text and put a ]
to make it valid JSON right, but this file size is around 1.5GB so I couldn't figure how to edit it in NodeJS in order to make it valid JSON file.
const fs = require('fs');
// Input and output file paths
const inputFile = 'input.json';
// Open the file for reading and writing
fs.open(inputFile, 'r+', (err, fd) => {
if (err) {
console.error('Error opening the input file:', err);
return;
}
// Move to the end of the file
fs.fstat(fd, (err, stats) => {
if (err) {
console.error('Error reading file information:', err);
fs.close(fd, () => console.log('Closed the input file due to error.'));
return;
}
const endPosition = stats.size;
// Create a buffer for reading
const buffer = Buffer.alloc(1); // Read only one byte (comma)
// Read the last byte in the file
fs.read(fd, buffer, 0, buffer.length, endPosition - 1, (err, bytesRead, data) => {
if (err) {
console.error('Error reading the last byte:', err);
fs.close(fd, () => console.log('Closed the input file due to error.'));
return;
}
// Check if the last byte is a comma
if (data[0] !== 44) { // Unicode code for comma is the same as ASCII
console.log('The last character is not a comma.');
fs.close(fd, () => console.log('Closed the input file.'));
return;
}
// If the last byte is a comma, replace it with a closing bracket
const closingBracket = Buffer.from(']', 'utf8'); // Use UTF-8 encoding
fs.write(fd, closingBracket, 0, closingBracket.length, endPosition - 1, (err) => {
if (err) {
console.error('Error writing to the file:', err);
} else {
console.log('Replaced the comma with a closing bracket.');
}
// Close the input file
fs.close(fd, () => console.log('Closed the input file after modification.'));
});
});
});
});