The result read-only property of the SVGFEOffsetElement interface describes the assigned name of an SVG filter primitive as an SVGAnimatedString.
It reflects the result attribute of the <feOffset> element, which offsets the input image relative to its current position. 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 <feOffset> 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 feOffsetElement = document.querySelector("feOffset");
const filterName = feOffsetElement.result;
console.log(filterName.baseVal); // the filter's assigned nameSVGFEOffsetElement.in1<custom-ident> data type