Properly save selection state when the selection root is the editor (#82

)

In cases where the cursor is at the beginning/end of the text or when all of the text is selected, window.getSelection() can specify the selection with respect to the editor instead of specific text nodes.
This change adds support for saving selection state in save() when this is the case.
Fixes #75

codejar.ts

@@ -138,6 +138,15 @@ export function CodeJar(editor: HTMLElement, highlight: (e: HTMLElement, pos?: P
     let {anchorNode, anchorOffset, focusNode, focusOffset} = s
     if (!anchorNode || !focusNode) throw 'error1'
 
+    // If the anchor and focus are the editor element, return either a full
+    // highlight or a start/end cursor position depending on the selection
+    if (anchorNode === editor && focusNode === editor) {
+      pos.start = (anchorOffset > 0 && editor.textContent) ? editor.textContent.length : 0
+      pos.end = (focusOffset > 0 && editor.textContent) ? editor.textContent.length : 0
+      pos.dir = (focusOffset >= anchorOffset) ? '->' : '<-'
+      return pos
+    }
+
     // Selection anchor and focus are expected to be text nodes,
     // so normalize them.
     if (anchorNode.nodeType === Node.ELEMENT_NODE) {