2D Texture Array from Image Failure.js

{
  let w = 128;
  let num_images = 3;
  let source_canvas = document.createElement('canvas');
  source_canvas.width = w;
  source_canvas.height = w * num_images * 2;
  let source_img = new Image();
  source_img.src = source_canvas.toDataURL('image/png');
  source_img.onload = function () {
    let canvas = document.createElement('canvas');
    let gl = canvas.getContext('webgl2');
    gl.bindTexture(gl.TEXTURE_2D_ARRAY, gl.createTexture());
    gl.texImage3D(gl.TEXTURE_2D_ARRAY, 5, gl.RGBA, 4, 4, num_images, 0, gl.RGBA, gl.UNSIGNED_BYTE, source_img);
    console.log(gl.getError());
    gl.texImage3D(gl.TEXTURE_2D_ARRAY, 5, gl.RGBA, 4, 4, num_images, 0, gl.RGBA, gl.UNSIGNED_BYTE, source_canvas);
    console.log(gl.getError());
  };
}