Use the templateId instead of template identity

This allows us to use a unified code path between rehydration and normal
rendering.

We also discovered that we don’t use `lastYielded.self` (it was an
accidental holdover from the code that was refactored into lastYielded),
so we removed it (along with a vestigial `shadowTemplate`, removed in a
previous commit).

Author: Godhuda

packages/htmlbars-compiler/tests/dirtying-test.js

@@ -650,7 +650,7 @@ test("it is possible to rehydrate a template with blocks", function() {
   let childMorph2 = env.dom.createMorphAt(span, 0, 0);
 
   let obj = { bool: true, name: "Yehuda" };
-  childMorph1.lastYielded = new LastYielded(obj, template.raw.templates[0], null);
+  childMorph1.lastYielded = new LastYielded(template.raw.templates[0].id);
 
   rootMorph.childNodes = [childMorph1];
   childMorph1.childNodes = [childMorph2];
@@ -691,14 +691,6 @@ test("it is possible to serialize a render node tree", function() {
 });
 
 test("it is possible to serialize a render node tree with recursive templates", function() {
-  env.hooks.rehydrateLastYielded = function(env, morph) {
-    morph.lastYielded.template = morph.lastYielded.templateId;
-  };
-
-  env.hooks.serializeLastYielded = function(env, morph) {
-    return morph.lastYielded.template;
-  };
-
   let template = compile('<p title="{{title}}">{{#if bool}}<span>{{name}}</span>{{/if}}</p>');
   let obj = { title: 'chancancode', name: 'Godfrey', bool: true };
   let result = template.render(obj, env);

packages/htmlbars-runtime/lib/hooks.js

@@ -79,7 +79,7 @@ import { linkParams } from "../htmlbars-util/morph-utils";
 */
 
 export function wrap(template) {
-  if (template === null) { return null;  }
+  if (template === null) { return null; }
 
   return {
     meta: template.meta,
@@ -140,11 +140,10 @@ function yieldTemplate(template, env, parentScope, morph, renderState, visitor)
 
     var scope = parentScope;
 
-    if (morph.lastYielded && morph.lastYielded.isStableTemplate(template)) {
+    if (morph.lastResult && morph.lastYielded.isStableTemplate(template)) {
       return morph.lastResult.revalidateWith(env, undefined, self, blockArguments, visitor);
     }
 
-
     // Check to make sure that we actually **need** a new scope, and can't
     // share the parent scope. Note that we need to move this check into
     // a host hook, because the host's notion of scope may require a new
@@ -153,17 +152,14 @@ function yieldTemplate(template, env, parentScope, morph, renderState, visitor)
       scope = env.hooks.createChildScope(parentScope);
     }
 
-    if (morph.lastYielded && morph.lastYielded.templateId) {
-      env.hooks.rehydrateLastYielded(env, morph);
-
-      if (morph.lastYielded.isStableTemplate(template)) {
-        let renderResult = RenderResult.rehydrate(env, scope, template, { renderNode: morph, self, blockArguments });
-        renderResult.render();
-        return;
-      }
+    // rehydration
+    if (morph.lastYielded && morph.lastYielded.isStableTemplate(template)) {
+      let renderResult = RenderResult.rehydrate(env, scope, template, { renderNode: morph, self, blockArguments });
+      renderResult.render();
+      return;
     }
 
-    morph.lastYielded = new LastYielded(self, template, null);
+    morph.lastYielded = new LastYielded(template.id);
 
     // Render the template that was selected by the helper
     render(template, env, scope, { renderNode: morph, self: self, blockArguments: blockArguments });
@@ -1048,8 +1044,6 @@ export default {
   linkRenderNode: linkRenderNode,
   partial: partial,
   subexpr: subexpr,
-  rehydrateLastYielded: null,
-  serializeLastYielded: null,
 
   // fundamental hooks with good default behavior
   bindBlock: bindBlock,

packages/htmlbars-runtime/lib/render.js

@@ -348,7 +348,7 @@ function _rehydrateNode(owner, renderNode, dom, context, cache) {
     case 'range':
       element = elementFromId(dom, context, renderNode.parentNode, cache);
       node = dom.createMorphAt(element, renderNode.firstNode, renderNode.lastNode);
-      node.lastYielded = LastYielded.fromTemplateId(renderNode.templateId);
+      node.lastYielded = new LastYielded(renderNode.templateId);
       node.childNodes = renderNode.childNodes && renderNode.childNodes.map(childNode => _rehydrateNode(node, childNode, dom, context, cache));
       break;
   }
@@ -395,7 +395,7 @@ function _serializeNode(env, renderNode, serializationContext) {
       type: 'range',
       childNodes: renderNode.childNodes && renderNode.childNodes.map(childNode => _serializeNode(env, childNode, serializationContext)),
       parentNode: idFromElement(dom, parent, serializationContext),
-      templateId: renderNode.lastYielded && env.hooks.serializeLastYielded(env, renderNode),
+      templateId: renderNode.lastYielded && renderNode.lastYielded.templateId,
       firstNode,
       lastNode
     };
@@ -441,18 +441,11 @@ function idFromElement(dom, element, serializationContext) {
   return id;
 }
 
-export function LastYielded(self, template, shadowTemplate, templateId) {
-  this.self = self;
-  this.template = template;
-  this.shadowTemplate = shadowTemplate;
+export function LastYielded(templateId) {
   this.templateId = templateId;
 }
 
-LastYielded.fromTemplateId = function(templateId)  {
-  return new LastYielded(null, null, null, templateId);
-};
-
 LastYielded.prototype.isStableTemplate = function(nextTemplate) {
-  return !this.shadowTemplate && nextTemplate === this.template;
+  return nextTemplate.id === this.templateId;
 };