Changing Zero Width Space handling strategy

ZWS allows to put caret into empty inline node in Chrome

This change goes from:

- content observer puts ZWS on nodes set to ''
- ZWS stays in nodes and is handled accordingly (selection, arrow keys,
backspace/delete keys etc.)

to:

- content observer puts ZWS on nodes set to ''
- content observer removes ZWS from nodes which .data changes
from 'ZWS' to other string
- special treatment of ZWS is necessary only on "empty" document text
elements, ie those whose container .data equals ZWS

diff --git a/modules/documentCanvas/canvas/canvas.js b/modules/documentCanvas/canvas/canvas.js
index 8ba871b..7428e10 100644 (file)
--- a/modules/documentCanvas/canvas/canvas.js
+++ b/modules/documentCanvas/canvas/canvas.js
@@ -320,8 +320,14 @@ $.extend(Canvas.prototype, {
             var observer = new MutationObserver(function(mutations) {
                 mutations.forEach(function(mutation) {
                     if(documentElement.DocumentTextElement.isContentContainer(mutation.target)) {
+                        observer.disconnect();
                         if(mutation.target.data === '')
                             mutation.target.data = utils.unicode.ZWS;
+                        else if(mutation.oldValue === utils.unicode.ZWS) {
+                            mutation.target.data = mutation.target.data.replace(utils.unicode.ZWS, '');
+                            canvas._moveCaretToTextElement(canvas.getDocumentElement(mutation.target), 'end');
+                        }
+                        observer.observe(canvas.d[0], config);
                         canvas.publisher('contentChanged');
                     }
                 });
@@ -739,40 +745,23 @@ $.extend(Cursor.prototype, {
             anchorElement = this.canvas.getDocumentElement(selection.anchorNode),
             focusElement = this.canvas.getDocumentElement(selection.focusNode);
         
-        var getOffset = function(where) {
-            var toret, node;
-            if(where === 'anchor') {
-                node = selection.anchorNode;
-                toret = selection.anchorOffset;
-            } else {
-                node = selection.focusNode;
-                toret = selection.focusOffset;
-            }
-                        
-            if(toret === 1 && node.data.charAt(0) === utils.unicode.ZWS)
-                toret = 0;
-            else if((toret === node.data.length - 1) && (node.data.charAt(node.data.length - 1) === utils.unicode.ZWS))
-                toret++;
-            return toret;
-        }
-
         if((!anchorElement) || (anchorElement instanceof documentElement.DocumentNodeElement) || (!focusElement) || focusElement instanceof documentElement.DocumentNodeElement)
             return {};
 
         if(which === 'anchor') {
             return {
                 element: anchorElement,
-                offset: getOffset('anchor'),
-                offsetAtBeginning: getOffset('anchor') === 0,
-                offsetAtEnd: selection.anchorNode.data.length === getOffset('anchor')
+                offset: selection.anchorOffset,
+                offsetAtBeginning: selection.anchorOffset === 0,
+                offsetAtEnd: selection.anchorNode.data.length === selection.anchorOffset
             };
         }
         if(which === 'focus') {
             return {
                 element: focusElement,
-                offset: getOffset('focus'),
-                offsetAtBeginning: getOffset('focus') === 0,
-                offsetAtEnd: selection.focusNode.data.length === getOffset('focus')
+                offset: selection.focusOffset,
+                offsetAtBeginning: selection.focusOffset === 0,
+                offsetAtEnd: selection.focusNode.data.length === selection.focusOffset
             };
         }
         
@@ -785,30 +774,30 @@ $.extend(Cursor.prototype, {
             if(anchorFirst) {
                 if(which === 'start') {
                     element = anchorElement;
-                    offset = getOffset('anchor')
+                    offset = selection.anchorOffset
                 }
                 else if(which === 'end') {
                     element = focusElement,
-                    offset = getOffset('focus')
+                    offset = selection.focusOffset
                 }
             } else {
                 if(which === 'start') {
                     element = focusElement,
-                    offset = getOffset('focus')
+                    offset = selection.focusOffset
                 }
                 else if(which === 'end') {
                     element = anchorElement;
-                    offset = getOffset('anchor')
+                    offset = selection.anchorOffset
                 }
             }
         } else {
             // TODO: Handle order via https://developer.mozilla.org/en-US/docs/Web/API/Node.compareDocumentPosition
             if(which === 'start') {
                 element = anchorElement;
-                offset = getOffset('anchor')
+                offset = selection.anchorOffset
             } else {
                 element = focusElement;
-                offset = getOffset('focus')
+                offset = selection.focusOffset
             }
         }
 

diff --git a/modules/documentCanvas/canvas/canvas.test3.js b/modules/documentCanvas/canvas/canvas.test3.js
index 477aca0..f96e0ff 100644 (file)
--- a/modules/documentCanvas/canvas/canvas.test3.js
+++ b/modules/documentCanvas/canvas/canvas.test3.js
@@ -13,6 +13,58 @@ var expect = chai.expect;
 
 describe('Canvas', function() {
 
+
+
+    describe('ZWS', function() {
+        var view, section, textElement;
+        
+        beforeEach(function() {
+            var c = canvas.fromXML('<section></section>');
+
+            section = c.doc();
+            textElement = section.children()[0];
+            view = c.view()[0];
+            document.getElementsByTagName('body')[0].appendChild(view);
+        });
+
+        afterEach(function() {
+            view.parentNode.removeChild(view);
+        });
+
+        var getTextContainerNode = function(textElement) {
+            return textElement.dom().contents()[0];
+        }
+
+        it('is set automatically on all empty DocumentTextElements', function() {
+            expect(getTextContainerNode(textElement).data).to.equal(utils.unicode.ZWS);
+
+            var header = section.append({tag: 'header'}),
+                newText = header.append({text: ''}),
+                textNode = getTextContainerNode(textElement);
+            
+            expect(textNode.data).to.equal(utils.unicode.ZWS);
+        });
+
+        it('is added automatically when whole text gets deleted', function() {
+            getTextContainerNode(textElement).data = '';
+            
+            window.setTimeout(function() {
+                expect(getTextContainerNode(textElement).data).to.equal(utils.unicode.ZWS);
+            }, 0)
+            
+            var header = section.append({tag: 'header'}),
+                newText = header.append({text: 'Alice'}),
+                textNode = getTextContainerNode(newText);
+
+            expect(textNode.data).to.have.length('Alice'.length);
+            textNode.data = '';
+
+            window.setTimeout(function() {
+                expect(textNode.data).to.equal(utils.unicode.ZWS);
+            }, 0)
+        });
+    });
+
     describe('Internal HTML representation of a DocumentNodeElement', function() {
         it('is always a div tag', function() {
             ['section', 'header', 'span', 'aside', 'figure'].forEach(function(tagName) {
@@ -1271,25 +1323,6 @@ describe('Canvas', function() {
             expect(cursor.isSelectingSiblings()).to.equal(false, '"has" and "big" are not children');
             
         })
-
-        describe('zero width space handling', function() {
-            it('position range includes ZWS at the boundries of text in case when native selection api doesn\'t', function() {
-                var c = canvas.fromXML("<section>Alice</section>"),
-                    dom = c.doc().dom(),
-                    textNode = findTextNode(dom, 'Alice'),
-                    cursor = c.getCursor();
-
-                textNode.data = utils.unicode.ZWS + 'Alice';
-                getSelection.returns({anchorNode: textNode, anchorOffset: 1, focusNode: textNode, focusOffset: 1});
-                expect(cursor.getPosition().offset).to.equal(0);
-                expect(cursor.getPosition().offsetAtBeginning).to.equal(true, 'offset at beginning');
-                
-                textNode.data = 'Alice' + utils.unicode.ZWS;
-                getSelection.returns({anchorNode: textNode, anchorOffset: 5, focusNode: textNode, focusOffset: 5});
-                expect(cursor.getPosition().offset).to.equal(6);
-                expect(cursor.getPosition().offsetAtEnd).to.equal(true, 'offset at end');
-            });
-        });
     });
 
     describe('Serializing document to WLXML', function() {