HTML5 canvas: is there a way to resize image with "nearest neighbour" resampling?

I wrote a NN resizing script a while ago using ImageData (around line 1794)

https://github.com/arahaya/ImageFilters.js/blob/master/imagefilters.js

You can see a demo here

http://www.arahaya.com/imagefilters/

unfortunately the builtin resizing should be slightly faster.

This CSS on the canvas element works:

image-rendering: pixelate;

This works in Chrome 93, as of September 2021.

image-rendering: -webkit-optimize-contrast; /* webkit */
image-rendering: -moz-crisp-edges /* Firefox */

http://phrogz.net/tmp/canvas_image_zoom.html can provide a fallback case using canvas and getImageData. In short:

// Create an offscreen canvas, draw an image to it, and fetch the pixels
var offtx = document.createElement('canvas').getContext('2d');
offtx.drawImage(img1,0,0);
var imgData = offtx.getImageData(0,0,img1.width,img1.height).data;

// Draw the zoomed-up pixels to a different canvas context
for (var x=0;x<img1.width;++x){
  for (var y=0;y<img1.height;++y){
    // Find the starting index in the one-dimensional image data
    var i = (y*img1.width + x)*4;
    var r = imgData[i  ];
    var g = imgData[i+1];
    var b = imgData[i+2];
    var a = imgData[i+3];
    ctx2.fillStyle = "rgba("+r+","+g+","+b+","+(a/255)+")";
    ctx2.fillRect(x*zoom,y*zoom,zoom,zoom);
  }
}

More: MDN docs on image-rendering