feat(dia.Graph): add transferCellEmbeds() and transferCellConnectedLinks()

packages/joint-core/src/dia/Cell.mjs

@@ -339,12 +339,25 @@ export const Cell = Model.extend({
         return this.set('parent', parent, opt);
     },
 
-    embed: function(cell, opt) {
+    embed: function(cell, opt = {}) {
         const cells = Array.isArray(cell) ? cell : [cell];
         if (!this.canEmbed(cells)) {
             throw new Error('Recursive embedding not allowed.');
         }
-        if (cells.some(c => c.isEmbedded() && this.id !== c.parent())) {
+        if (opt.reparent) {
+            const parents = uniq(cells.map(c => c.getParentCell()));
+
+            // Unembed cells from their current parents.
+            parents.forEach((parent) => {
+                // Cell doesn't have to be embedded.
+                if (!parent) return;
+
+                // Pass all the `cells` since the `dia.Cell._unembedCells` method can handle cases
+                // where not all elements of `cells` are embedded in the same parent.
+                parent._unembedCells(cells, opt);
+            });
+
+        } else if (cells.some(c => c.isEmbedded() && this.id !== c.parent())) {
             throw new Error('Embedding of already embedded cells is not allowed.');
         }
         this._embedCells(cells, opt);

packages/joint-core/src/dia/Graph.mjs

@@ -396,6 +396,39 @@ export const Graph = Model.extend({
         this.get('cells').remove(cell, { silent: true });
     },
 
+    transferCellEmbeds: function(sourceCell, targetCell, opt = {}) {
+
+        const batchName = 'transfer-embeds';
+        this.startBatch(batchName);
+
+        // Embed children of the source cell in the target cell.
+        const children = sourceCell.getEmbeddedCells();
+        targetCell.embed(children, { ...opt, reparent: true });
+
+        this.stopBatch(batchName);
+    },
+
+    transferCellConnectedLinks: function(sourceCell, targetCell, opt = {}) {
+
+        const batchName = 'transfer-connected-links';
+        this.startBatch(batchName);
+
+        // Reconnect all the links connected to the old cell to the new cell.
+        const connectedLinks = this.getConnectedLinks(sourceCell, opt);
+        connectedLinks.forEach((link) => {
+
+            if (link.getSourceCell() === sourceCell) {
+                link.prop(['source', 'id'], targetCell.id, opt);
+            }
+
+            if (link.getTargetCell() === sourceCell) {
+                link.prop(['target', 'id'], targetCell.id, opt);
+            }
+        });
+
+        this.stopBatch(batchName);
+    },
+
     // Get a cell by `id`.
     getCell: function(id) {
 

packages/joint-core/test/jointjs/cell.js

@@ -256,6 +256,36 @@ QUnit.module('cell', function(hooks) {
 
             assert.raises(() => { cell3.embed(cell2); }, /Embedding of already embedded cells is not allowed/, 'throws exception on embedding of embedded cell');
         });
+
+        QUnit.test('opt.reparent = true', function(assert) {
+
+            const cell1 = new joint.shapes.standard.Rectangle({
+                position: { x: 20, y: 20 },
+                size: { width: 60, height: 60 }
+            });
+            const cell2 = new joint.shapes.standard.Rectangle({
+                position: { x: 20, y: 20 },
+                size: { width: 60, height: 60 }
+            });
+            const cell3 = new joint.shapes.standard.Rectangle({
+                position: { x: 20, y: 20 },
+                size: { width: 60, height: 60 }
+            });
+            const cell4 = new joint.shapes.standard.Rectangle({
+                position: { x: 20, y: 20 },
+                size: { width: 60, height: 60 }
+            });
+
+            this.graph.addCells([cell1, cell2, cell3, cell4]);
+
+            cell1.embed(cell2);
+            cell3.embed([cell2, cell4], { reparent: true });
+
+            assert.equal(cell1.getEmbeddedCells().length, 0);
+            assert.equal(cell2.parent(), cell3.id);
+            assert.equal(cell3.getEmbeddedCells()[0].id, cell2.id);
+            assert.equal(cell3.getEmbeddedCells()[1].id, cell4.id);
+        });
     });
 
     QUnit.module('remove attributes', function(hooks) {

packages/joint-core/test/jointjs/graph.js

@@ -1546,4 +1546,109 @@ QUnit.module('graph', function(hooks) {
             assert.notOk(graph.hasActiveBatch());
         });
     });
+
+    QUnit.module('graph.transferCellEmbeds()', function() {
+
+        QUnit.test('should transfer embeds from one element to another', function(assert) {
+
+            const originalElement = new joint.shapes.standard.Rectangle();
+            const child = new joint.shapes.standard.Rectangle();
+            const replacementElement = new joint.shapes.standard.Rectangle();
+
+            originalElement.embed(child);
+
+            this.graph.addCells([originalElement, child, replacementElement]);
+            this.graph.transferCellEmbeds(originalElement, replacementElement);
+
+            assert.equal(replacementElement.getEmbeddedCells()[0], child);
+            assert.equal(originalElement.getEmbeddedCells().length, 0);
+        });
+
+        QUnit.test('should transfer embeds from an element to a link', function(assert) {
+
+            const link = new joint.shapes.standard.Link();
+            const child = new joint.shapes.standard.Rectangle();
+            const element = new joint.shapes.standard.Rectangle();
+
+            element.embed(child);
+
+            this.graph.addCells([link, child, element]);
+            this.graph.transferCellEmbeds(element, link);
+
+            assert.equal(link.getEmbeddedCells()[0], child);
+            assert.equal(element.getEmbeddedCells().length, 0);
+        });
+    });
+
+    QUnit.module('graph.transferCellConnectedLinks()', function() {
+
+        QUnit.test('should transfer links of an element', function(assert) {
+
+            const originalElement = new joint.shapes.standard.Rectangle();
+            const link1 = new joint.shapes.standard.Link({ source: { id: originalElement.id }});
+            const link2 = new joint.shapes.standard.Link({ target: { id: originalElement.id }});
+            const replacementElement = new joint.shapes.standard.Rectangle();
+
+            this.graph.addCells([originalElement, link1, link2, replacementElement]);
+            this.graph.transferCellConnectedLinks(originalElement, replacementElement);
+
+            assert.equal(link1.source().id, replacementElement.id);
+            assert.equal(link2.target().id, replacementElement.id);
+        });
+
+        QUnit.test('should transfer links of a link', function(assert) {
+
+            const originalLink = new joint.shapes.standard.Link();
+            const link1 = new joint.shapes.standard.Link({ source: { id: originalLink.id }});
+            const link2 = new joint.shapes.standard.Link({ target: { id: originalLink.id }});
+            const replacementLink = new joint.shapes.standard.Link();
+
+            this.graph.addCells([originalLink, link1, link2, replacementLink]);
+            this.graph.transferCellConnectedLinks(originalLink, replacementLink);
+
+            assert.equal(link1.source().id, replacementLink.id);
+            assert.equal(link2.target().id, replacementLink.id);
+        });
+
+        QUnit.test('should work when transferring links from a link to an element', function(assert) {
+
+            const originalLink = new joint.shapes.standard.Link();
+            const link1 = new joint.shapes.standard.Link({ source: { id: originalLink.id }});
+            const link2 = new joint.shapes.standard.Link({ target: { id: originalLink.id }});
+            const element = new joint.shapes.standard.Rectangle();
+
+            this.graph.addCells([originalLink, link1, link2, element]);
+            this.graph.transferCellConnectedLinks(originalLink, element);
+
+            assert.equal(link1.source().id, element.id);
+            assert.equal(link2.target().id, element.id);
+        });
+
+        QUnit.test('should work when transferring links from an element to a link', function(assert) {
+
+            const originalElement = new joint.shapes.standard.Rectangle();
+            const link1 = new joint.shapes.standard.Link({ source: { id: originalElement.id }});
+            const link2 = new joint.shapes.standard.Link({ target: { id: originalElement.id }});
+            const replacementLink = new joint.shapes.standard.Link();
+
+            this.graph.addCells([originalElement, link1, link2, replacementLink]);
+            this.graph.transferCellConnectedLinks(originalElement, replacementLink);
+
+            assert.equal(link1.source().id, replacementLink.id);
+            assert.equal(link2.target().id, replacementLink.id);
+        });
+
+        QUnit.test('should work with loop links', function(assert) {
+
+            const originalElement = new joint.shapes.standard.Rectangle();
+            const link = new joint.shapes.standard.Link({ source: { id: originalElement.id }, target: { id: originalElement.id }});
+            const replacementElement = new joint.shapes.standard.Rectangle();
+
+            this.graph.addCells([originalElement, link, replacementElement]);
+            this.graph.transferCellConnectedLinks(originalElement, replacementElement);
+
+            assert.equal(link.source().id, replacementElement.id);
+            assert.equal(link.target().id, replacementElement.id);
+        });
+    });
 });

packages/joint-core/types/joint.d.ts

@@ -263,6 +263,10 @@ export namespace dia {
 
         removeCells(cells: Cell[], opt?: Cell.DisconnectableOptions): this;
 
+        transferCellEmbeds(sourceCell: Cell, targetCell: Cell, opt?: S): void;
+
+        transferCellConnectedLinks(sourceCell: Cell, targetCell: Cell, opt?: Graph.ConnectionOptions): void;
+
         resize(width: number, height: number, opt?: S): this;
 
         resizeCells(width: number, height: number, cells: Cell[], opt?: S): this;
@@ -307,6 +311,10 @@ export namespace dia {
             [key: string]: any;
         }
 
+        interface EmbedOptions extends Options {
+            reparent?: boolean;
+        }
+
         interface EmbeddableOptions<T = boolean> extends Options {
             deep?: T;
         }
@@ -439,7 +447,7 @@ export namespace dia {
 
         stopTransitions(path?: string, delim?: string): this;
 
-        embed(cell: Cell | Cell[], opt?: Graph.Options): this;
+        embed(cell: Cell | Cell[], opt?: Cell.EmbedOptions): this;
 
         unembed(cell: Cell | Cell[], opt?: Graph.Options): this;