The width read-only property of the SVGFEComponentTransferElement interface describes the horizontal size of an SVG filter primitive as a SVGAnimatedLength.
It reflects the <feComponentTransfer> element's width filter primitive attribute. The attribute is a <length> or a <percentage> relative to the width of the filter region. The default value is 100%. The property value is a length in user coordinate system units.
const feComponentTransfer = document.querySelector("feComponentTransfer");
const horizontalSize = feComponentTransfer.width;
console.log(horizontalSize.baseVal.value); // the `width` value