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method Deno.FsFile.prototype.truncateSync

Synchronously truncates (or extends) the file to reach the specified len. If len is not specified, then the entire file contents are truncated.

Truncate the entire file

const file = Deno.openSync("my_file.txt", { write: true });
file.truncateSync();
file.close();

Truncate part of the file

// if "my_file.txt" contains the text "hello world":
const file = Deno.openSync("my_file.txt", { write: true });
file.truncateSync(7);
const buf = new Uint8Array(100);
file.readSync(buf);
const text = new TextDecoder().decode(buf); // "hello w"
file.close();

Parameters

optional
len: number