DeprecationWarning: Buffer() is deprecated

[denis-migdal]

Hi,

When using canvas.toBuffer(), we get the following error :

(node:998380) [DEP0005] DeprecationWarning: Buffer() is deprecated due to security and usability issues. Please use the Buffer.alloc(), Buffer.allocUnsafe(), or Buffer.from() methods instead.

Code :

import {Canvas} from "canvas";

const canvas = new Canvas(W,H);
// do stuff

canvas.toBuffer()

See also : https://stackoverflow.com/a/52257416

Deno : deno 2.4.5 (stable, release, x86_64-unknown-linux-gnu) - v8 13.7.152.14-rusty - typescript 5.8.3
Canvas : 3.2.0

[Whobeu]

I wonder if it is a Deno issue. I am running Node 22.19.0 under Windows 10 with canvas 3.2.0 and this code snippet does not throw an warning:

  return new Promise((resolve, reject) => {
    canvas.toBuffer((error, buffer) => {
      chart.destroy();
      if (error) {
        return reject(error);
      }
      return resolve(buffer);
    }, "image/png");
  });

Under ARM64 Debian bookworm with node 24.7.0 and the same code I am not seeing it either.

Unrelated to this package but related to Buffer, I use a package called node-apng. The module calls Buffer.slice() which is flagged by node as deprecated since 16.0.0. The replacement is Buffer.subarray(). It seems that under the hood in node, Buffer.slice() calls Buffer.subarray().

[denis-migdal]

Indeed, I do not have the warning with node.

I didn't find a way to trace the depreciation.
I just created an issue in Deno's Github : denoland/deno#30584

Let's see if they think it comes from their side or not.

[Whobeu]

I tested with Bun 1.2.21 and there is no deprecation warning with that runtime either.

[tancred423]

For reference, Deno confirmed this bug on their end and fixed it here: denoland/deno#31245
However, this just happened yesterday so we will have to wait for the next Deno release.