function promises.appendFile
Usage in Deno
import { promises } from "node:fs"; const { appendFile } = promises;
appendFile(): Promise<void>
Asynchronously append data to a file, creating the file if it does not yet
exist. data can be a string or a Buffer.
If options is a string, then it specifies the encoding.
The mode option only affects the newly created file. See fs.open() for more details.
The path may be specified as a FileHandle that has been opened
for appending (using fsPromises.open()).
path: PathLike | FileHandle
filename or {FileHandle}
Promise<void>
Fulfills with undefined upon success.