Utils: Use temporary text node for rect fallback

utils/dom.js

@@ -1,14 +1,14 @@
 /**
  * External dependencies
  */
-import { includes, first } from 'lodash';
+import { includes } from 'lodash';
 import tinymce from 'tinymce';
 
 /**
  * Browser dependencies
  */
 const { getComputedStyle } = window;
-const { TEXT_NODE, ELEMENT_NODE } = window.Node;
+const { TEXT_NODE } = window.Node;
 
 /**
  * Check whether the selection is horizontally at the edge of the container.
@@ -129,35 +129,19 @@ export function getRectangleFromRange( range ) {
 		return range.getBoundingClientRect();
 	}
 
-	const { startContainer, startOffset } = range;
+	let rect = range.getClientRects()[ 0 ];
 
 	// If the collapsed range starts (and therefore ends) at an element node,
-	// `getClientRects` will return undefined. To fix this we can get the
-	// selected child node and calculate a rectangle for that.
-	if ( startContainer.nodeType === ELEMENT_NODE ) {
-		const { childNodes } = startContainer;
-		const selectedNode = childNodes[
-			// Make sure there can be no errors.
-			Math.min( startOffset, childNodes.length - 1 )
-		];
-
-		if ( selectedNode.nodeType === ELEMENT_NODE ) {
-			return selectedNode.getBoundingClientRect();
-		}
-
-		// Text nodes have no `getBoundingClientRect` method, so create a range.
-		range = document.createRange();
-		range.setStart( selectedNode, 0 );
-		range.setEnd( selectedNode, 0 );
-
-		return range.getBoundingClientRect();
+	// `getClientRects` can be empty in some browsers. This can be resolved
+	// by adding a temporary text node to the range.
+	if ( ! rect ) {
+		const padNode = document.createTextNode( '\u200b' );
+		range.insertNode( padNode );
+		rect = range.getClientRects()[ 0 ];
+		padNode.parentNode.removeChild( padNode );
 	}
 
-	// For normal collapsed ranges (exception above), the bounding rectangle of
-	// the range may be inaccurate in some browsers. There will only be one
-	// rectangle since it is a collapsed range, so it is safe to pass this as
-	// the union of them. This works consistently in all browsers.
-	return first( range.getClientRects() );
+	return rect;
 }
 
 /**