denoland-deno/cli/tests/node_compat/test/parallel/test-buffer-zero-fill-cli.js

// deno-fmt-ignore-file
// deno-lint-ignore-file

// Copyright Joyent and Node contributors. All rights reserved. MIT license.
// Taken from Node 18.12.1
// This file is automatically generated by `tools/node_compat/setup.ts`. Do not modify this file manually.

'use strict';
// Flags: --zero-fill-buffers

// when using --zero-fill-buffers, every Buffer and SlowBuffer
// instance must be zero filled upon creation

require('../common');
const SlowBuffer = require('buffer').SlowBuffer;
const assert = require('assert');

function isZeroFilled(buf) {
  for (const n of buf)
    if (n > 0) return false;
  return true;
}

// This can be somewhat unreliable because the
// allocated memory might just already happen to
// contain all zeroes. The test is run multiple
// times to improve the reliability.
for (let i = 0; i < 50; i++) {
  const bufs = [
    Buffer.alloc(20),
    Buffer.allocUnsafe(20),
    SlowBuffer(20),
    Buffer(20),
    new SlowBuffer(20),
  ];
  for (const buf of bufs) {
    assert(isZeroFilled(buf));
  }
}