basic support for non-editable parts

e.g. pills, they get deleted when any character of them is removed
later on we also shouldn't allow the caret to be set inside of them

src/editor/model.js

@@ -20,7 +20,6 @@ export default class EditorModel {
     constructor(parts, partCreator) {
         this._parts = parts;
         this._partCreator = partCreator;
-        this._previousValue = parts.reduce((text, p) => text + p.text, "");
         this._activePartIdx = null;
         this._autoComplete = null;
         this._autoCompletePartIdx = null;
@@ -68,19 +67,19 @@ export default class EditorModel {
     _diff(newValue, inputType, caret) {
         // handle deleteContentForward (Delete key)
         // and deleteContentBackward (Backspace)
-
+        const previousValue = this.parts.reduce((text, p) => text + p.text, "");
         // can't use caret position with drag and drop
         if (inputType === "deleteByDrag") {
-            return diffDeletion(this._previousValue, newValue);
+            return diffDeletion(previousValue, newValue);
         } else {
-            return diffAtCaret(this._previousValue, newValue, caret.offset);
+            return diffAtCaret(previousValue, newValue, caret.offset);
         }
     }
 
     update(newValue, inputType, caret) {
         const diff = this._diff(newValue, inputType, caret);
         const position = this._positionForOffset(diff.at, caret.atNodeEnd);
-        console.log("update at", {position, diff, newValue, prevValue: this._previousValue});
+        console.log("update at", {position, diff, newValue, prevValue: this.parts.reduce((text, p) => text + p.text, "")});
         if (diff.removed) {
             this._removeText(position, diff.removed.length);
         }
@@ -88,7 +87,6 @@ export default class EditorModel {
             this._addText(position, diff.added);
         }
         this._mergeAdjacentParts();
-        this._previousValue = newValue;
         const caretOffset = diff.at + (diff.added ? diff.added.length : 0);
         const newPosition = this._positionForOffset(caretOffset, true);
         this._setActivePart(newPosition);
@@ -141,9 +139,10 @@ export default class EditorModel {
 
     _removeText(pos, len) {
         let {index, offset} = pos;
-        while (len !== 0) {
+        while (len > 0) {
             // part might be undefined here
             let part = this._parts[index];
+            if (part.canEdit) {
                 const amount = Math.min(len, part.text.length - offset);
                 const replaceWith = part.remove(offset, amount);
                 if (typeof replaceWith === "string") {
@@ -158,6 +157,10 @@ export default class EditorModel {
                 }
                 len -= amount;
                 offset = 0;
+            } else {
+                len = part.length - (offset + len);
+                this._removePart(index);
+            }
         }
     }
 

src/editor/parts.js

@@ -91,6 +91,10 @@ class BasePart {
     get text() {
         return this._text;
     }
+
+    get canEdit() {
+        return true;
+    }
 }
 
 export class PlainPart extends BasePart {
@@ -165,6 +169,10 @@ class PillPart extends BasePart {
                node.childNodes.length === 1 &&
                node.childNodes[0].nodeType === Node.TEXT_NODE;
     }
+
+    get canEdit() {
+        return false;
+    }
 }
 
 export class RoomPillPart extends PillPart {