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Looking at the examples for Uint8ClampedArray and Uint8Array , it looks like the difference is how values are treated when assigned.

If you are trying to set one element to a clamped array to any value outside of the range 0-255 , it will simply default to 0 or 255 (depending on whether the value is smaller or larger). A normal Uint8Array array just takes the first 8 bit of the value.

Examples:

var x = new Uint8ClampedArray([17, -45.3]);
console.log(x[0]); // 17
console.log(x[1]); // 0
console.log(x.length); // 2
var x = new Uint8Array([17, -45.3]);
console.log(x[0]); // 17
console.log(x[1]); // 211
console.log(x.length); // 2
                Note also that Uint8Array([0.9]) is [0], but Uint8ClampedArray([0.9]) is [1], ie. the clamped version uses rounding, but the basic version uses floor.
– dan-man
                May 16, 2016 at 9:22
                The OP mentioned this was used for pixel values in the canvas, is this a shortcut for saturated arithmetic?
– Indolering
                Sep 30, 2016 at 19:54
                I think Uint8Array would be faster - unless you were using the clamping features for graphics, which maybe faster in that case.
– Tomachi
                Nov 2, 2018 at 10:39
                @llya These are for image/video/audio process. The main feature is: it never overflow/underflow.  When you are trying to increase the brightness in an image: max brightness (255)+1 should give 255, not overflow to zero.
– J-16 SDiZ
                Apr 4, 2019 at 6:26
        
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