Usage in Deno
import { appendFile } from "node:fs";
appendFile(path: PathOrFileDescriptor,data: string | Uint8Array,options: WriteFileOptions,callback: NoParamCallback,): void
Asynchronously append data to a file, creating the file if it does not yet
exist. data can be a string or a Buffer.
The mode option only affects the newly created file. See open for more details.
import { appendFile } from 'node:fs';
appendFile('message.txt', 'data to append', (err) => {
if (err) throw err;
console.log('The "data to append" was appended to file!');
});
If options is a string, then it specifies the encoding:
import { appendFile } from 'node:fs';
appendFile('message.txt', 'data to append', 'utf8', callback);
The path may be specified as a numeric file descriptor that has been opened
for appending (using fs.open() or fs.openSync()). The file descriptor will
not be closed automatically.
import { open, close, appendFile } from 'node:fs';
function closeFd(fd) {
close(fd, (err) => {
if (err) throw err;
});
}
open('message.txt', 'a', (err, fd) => {
if (err) throw err;
try {
appendFile(fd, 'data to append', 'utf8', (err) => {
closeFd(fd);
if (err) throw err;
});
} catch (err) {
closeFd(fd);
throw err;
}
});
path: PathOrFileDescriptor
filename or file descriptor
options: WriteFileOptions
callback: NoParamCallback
void
appendFile(): void
Asynchronously append data to a file, creating the file if it does not exist.
file: PathOrFileDescriptor
A path to a file. If a URL is provided, it must use the file: protocol.
If a file descriptor is provided, the underlying file will not be closed automatically.
The data to write. If something other than a Buffer or Uint8Array is provided, the value is coerced to a string.
callback: NoParamCallback
void