Deno.readSync - Deno documentation
function Deno.readSync
rid: number,
buffer: Uint8Array,
): number | null

This will be removed in Deno 2.0. See the Deno 1.x to 2.x Migration Guide for migration instructions.

Synchronously read from a resource ID (rid) into an array buffer (buffer).

Returns either the number of bytes read during the operation or EOF (null) if there was nothing more to read.

It is possible for a read to successfully return with 0 bytes. This does not indicate EOF.

This function is one of the lowest level APIs and most users should not work with this directly, but rather use ReadableStream and toArrayBuffer instead.

It is not guaranteed that the full buffer will be read in a single call.

// if "/foo/bar.txt" contains the text "hello world":
using file = Deno.openSync("/foo/bar.txt");
const buf = new Uint8Array(100);
const numberOfBytesRead = Deno.readSync(file.rid, buf); // 11 bytes
const text = new TextDecoder().decode(buf);  // "hello world"


rid: number
buffer: Uint8Array

Return Type

number | null