The result read-only property of the SVGFESpecularLightingElement interface describes the assigned name of an SVG filter primitive as a SVGAnimatedString.
It reflects the result attribute of the <feSpecularLighting> element, which lights a source graphic using the alpha channel as a bump map. The attribute value is a <custom-ident>. If supplied, then graphics that result from processing this filter primitive can be referenced by an in attribute on a subsequent filter primitive within the same <filter> element.
If no result attribute is defined, the filter's result.baseVal and result.animVal are empty strings, and the output of the <feSpecularLighting> filter will only be available for re-use as the implicit input into the next filter primitive if that filter primitive provides no value for its in attribute.
const feSpecularLightingElement = document.querySelector("feSpecularLighting");
const filterName = feSpecularLightingElement.result;
console.log(filterName.baseVal); // the filter's assigned nameSVGFESpecularLightingElement.in1<custom-ident> data typeSVGFEDiffuseLightingElementlighting-color property