The Range.setEnd() method sets the end position of a Range to be located at the given offset into the specified node x.Setting the end point above (higher in the document) than the start point will result in a collapsed range with the start and end points both set to the specified end position.
setEnd(endNode, endOffset)
If the endNode is a Node of type Text, Comment, or CDataSection, then endOffset is the number of characters from the start of endNode. For other Node types, endOffset is the number of child nodes between the start of the endNode.
const range = document.createRange();
const endNode = document.getElementsByTagName("p").item(3);
const endOffset = endNode.childNodes.length;
range.setEnd(endNode, endOffset);
Note: setEnd() is commonly used in conjunction with setStart() to fully configure a range.