add support for automatically linking data roots of ractive instances…

… from any model

src/model/Model.js

@@ -1,4 +1,4 @@
-import ModelBase, { maybeBind, shuffle } from './ModelBase';
+import ModelBase, { checkDataLink, maybeBind, shuffle } from './ModelBase';
 import LinkModel from './LinkModel'; // eslint-disable-line no-unused-vars
 import getComputationSignature from 'src/Ractive/helpers/getComputationSignature';
 import { capture } from 'src/global/capture';
@@ -146,6 +146,8 @@ export default class Model extends ModelBase {
       this.adapt();
     }
 
+    if (this.dataModel) checkDataLink(this, value);
+
     // keep track of array stuff
     if (isArray(value)) {
       this.length = value.length;
@@ -236,6 +238,14 @@ export default class Model extends ModelBase {
       child = new Model(this, key);
       this.children.push(child);
       this.childByKey[key] = child;
+
+      if (key === 'data') {
+        const val = this.retrieve();
+        if (val && val.viewmodel && val.viewmodel.isRoot) {
+          child.link(val.viewmodel, 'data');
+          this.dataModel = val;
+        }
+      }
     }
 
     if (child._link && (!opts || opts.lastLink !== false)) return child._link;
@@ -249,6 +259,8 @@ export default class Model extends ModelBase {
     const old = this.value;
     const value = this.retrieve();
 
+    if (this.dataModel) checkDataLink(this, value);
+
     if (force || !isEqual(value, old)) {
       this.value = value;
       if (this.boundValue) this.boundValue = null;

src/model/ModelBase.js

@@ -202,7 +202,10 @@ export default class ModelBase {
     i = this.children.length;
     while (i--) {
       const child = this.children[i];
-      child.rebind(next ? next.joinKey(child.key) : undefined, child, safe);
+      child.rebind(next ? next.joinKey(child.key) : undefined, child._link || child, safe);
+      if (this.dataModel) {
+        this.addShuffleTask(() => checkDataLink(this, this.retrieve()), 'early');
+      }
     }
 
     i = this.bindings.length;
@@ -358,3 +361,14 @@ export function shuffle(model, newIndices, link, unsafe) {
 
   model.shuffling = false;
 }
+
+export function checkDataLink(model, value) {
+  if (model.dataModel && value !== model.dataModel) {
+    if (value && value.viewmodel && value.viewmodel.isRoot) {
+      model.childByKey.data.link(value.viewmodel, 'data');
+      model.dataModel = value;
+    } else {
+      model.childByKey.data.unlink();
+    }
+  }
+}

tests/browser/references.js

@@ -779,4 +779,43 @@ export default function() {
 
     t.strictEqual(r.getContext('.bar').get('@macro.foo.bar.baz'), 42);
   });
+
+  test(`joining instance data grabs the viewmodel of the instance`, t => {
+    const c1 = new Ractive({ data: { what: 42 } });
+    const c2 = new Ractive({ data: { what: 99 } });
+
+    const r = new Ractive({
+      target: fixture,
+      template: '{{child.data.what}}',
+      data: { child: c1 }
+    });
+
+    t.equal(fixture.innerHTML, '42');
+
+    r.set('child', c2);
+    t.equal(fixture.innerHTML, '99');
+  });
+
+  test(`automatic linking of instance data in an each`, t => {
+    const c1 = new Ractive({ data: { what: 42 } });
+    const c2 = new Ractive({ data: { what: 99 } });
+    const c3 = new Ractive({ data: { what: 2 } });
+
+    const r = new Ractive({
+      target: fixture,
+      template: '{{#each children}}{{.data.what}}|{{/each}}',
+      data: { children: [c1, c2] }
+    });
+
+    t.equal(fixture.innerHTML, '42|99|');
+
+    r.shift('children');
+    t.equal(fixture.innerHTML, '99|');
+
+    r.push('children', c1);
+    t.equal(fixture.innerHTML, '99|42|');
+
+    r.unshift('children', c3);
+    t.equal(fixture.innerHTML, '2|99|42|');
+  });
 }