Fix deleteAtRange with nested blocks (#594)

* Add failing test for backspace in a nested block

* Fix deleteAtRange

* Move to test to delete-at-range

* Use and improve getHighestOnlyChildParent

src/models/node.js

@@ -658,15 +658,20 @@ const Node = {
    */
 
   getHighestOnlyChildParent(key) {
-    let child = this.assertDescendant(key)
-    let match = null
-    let parent
+    const ancestors = this.getAncestors(key)
 
-    while (parent = this.getParent(child)) {
-      if (parent == null || parent.nodes.size > 1) return match
-      match = parent
-      child = parent
+    if (!ancestors) {
+      key = Normalize.key(key)
+      throw new Error(`Could not find a descendant node with key "${key}".`)
     }
+
+    return ancestors
+      // Skip this node
+      .skipLast()
+      // Take parents until there are more than one child
+      .reverse().takeUntil(p => p.nodes.size > 1)
+      // Pick the highest
+      .last()
   },
 
   /**

src/transforms/at-range.js

@@ -111,7 +111,8 @@ export function deleteAtRange(transform, range, options = {}) {
       transform.moveNodeByKey(child.key, newKey, newIndex, OPTS)
     })
 
-    const lonely = document.getFurthest(endBlock.key, p => p.nodes.size == 1) || endBlock
+    // Remove parents of endBlock as long as they have a single child
+    const lonely = document.getHighestOnlyChildParent(endBlock.key) || endBlock
     transform.removeNodeByKey(lonely.key, OPTS)
   }
 

test/transforms/fixtures/at-range/delete-at-range/double-nested-block/index.js

@@ -0,0 +1,7 @@
+
+export default function (state) {
+  return state
+    .transform()
+    .deleteAtRange(state.selection)
+    .apply()
+}

test/transforms/fixtures/at-range/delete-at-range/double-nested-block/input.yaml

@@ -0,0 +1,32 @@
+
+document:
+  key: a
+  nodes:
+  - key: b
+    kind: block
+    type: list
+    nodes:
+    - key: c
+      kind: block
+      type: item
+      nodes:
+      - key: d
+        kind: block
+        type: line
+        nodes:
+        - key: e
+          kind: text
+          text: "Text"
+      - key: f
+        kind: block
+        type: line
+        nodes:
+        - key: g
+          kind: text
+          text: ""
+selection:
+  anchorKey: e
+  anchorOffset: 4
+  focusKey: g
+  focusOffset: 0
+  isFocused: true

test/transforms/fixtures/at-range/delete-at-range/double-nested-block/output.yaml

@@ -0,0 +1,13 @@
+
+nodes:
+- kind: block
+  type: list
+  nodes:
+  - kind: block
+    type: item
+    nodes:
+    - kind: block
+      type: line
+      nodes:
+      - kind: text
+        text: "Text"