Currently, the fs.writeFile[Sync]() description states:
Asynchronously writes data to a file, replacing the file if it already exists.
However, this is only true if the first argument is a filename. If it is a file descriptor, the file content is not truncated (as somebody may expect) and a new data is merged from the 0 position into the old data.
- Compare
fs.readFileSync() behavior:
'use strict';
const fs = require('fs');
const fileName = 'test.txt';
fs.writeFileSync(fileName, '123');
fs.writeFileSync(fileName, '0');
console.log(fs.readFileSync(fileName, 'utf8'));
fs.unlinkSync(fileName);
const fd = fs.openSync(fileName, 'w');
fs.writeFileSync(fd, '123');
fs.writeFileSync(fd, '0');
fs.closeSync(fd);
console.log(fs.readFileSync(fileName, 'utf8'));
fs.unlinkSync(fileName);
- Compare the same
fs.writeFile() behavior:
const fs = require('fs');
const fileName = 'test.txt';
fs.writeFile(fileName, '123', () => {
fs.writeFile(fileName, '0', () => {
console.log(fs.readFileSync(fileName, 'utf8'));
fs.unlinkSync(fileName);
const fd = fs.openSync(fileName, 'w');
fs.writeFile(fd, '123', () => {
fs.writeFile(fd, '0', () => {
fs.closeSync(fd);
console.log(fs.readFileSync(fileName, 'utf8'));
fs.unlinkSync(fileName);
});
});
});
});If this is intended behavior, should we make the description more accurate?
Currently, the
fs.writeFile[Sync]()description states:However, this is only true if the first argument is a filename. If it is a file descriptor, the file content is not truncated (as somebody may expect) and a new data is merged from the
0position into the old data.fs.readFileSync()behavior:fs.writeFile()behavior:If this is intended behavior, should we make the description more accurate?