function Deno.truncate
truncate(name: string,len?: number,): Promise<void>
Truncates (or extends) the specified file, to reach the specified len.
If len is not specified then the entire file contents are truncated.
Truncate the entire file
await Deno.truncate("my_file.txt");
Truncate part of the file
const file = await Deno.makeTempFile();
await Deno.writeTextFile(file, "Hello World");
await Deno.truncate(file, 7);
const data = await Deno.readFile(file);
console.log(new TextDecoder().decode(data)); // "Hello W"
Requires allow-write permission.
Promise<void>