Adapter assignments refactoring, specs and readme clarification

Author: dhilt

README.md

@@ -148,11 +148,11 @@ It is empty since it was deprecated in v1.6.0.
 >{{item}}</div>
 ```
 
-### Parametrs
+### Parameters
 
 * **uiScroll – scroll expression** – The expression indicating how to enumerate a collection. Only one format is currently supported: `variable in datasource` – where variable is the user defined loop variable and datasource is the name of the data source to enumerate.
-* **buffer-size - expression**, optional - number of items requested from the datasource in a single request. The default is 10 and the minimal value is 3
-* **padding - expression**, optional - extra height added to the visible area for the purpose of determining when the items should be created/destroyed. The value is relative to the visible height of the area, the default is 0.5 and the minimal value is 0.3
+* **buffer-size - expression**, optional - number of items requested from the datasource in a single request. The default is 10 and the minimal value is 3.
+* **padding - expression**, optional - extra height added to the visible area for the purpose of determining when the items should be created/destroyed. The value is relative to the visible height of the area, the default is 0.5 and the minimal value is 0.3.
 * **start-index - expression**, optional - index of the first item to be requested from the datasource. The default is 1.
 * **adapter - assignable expression**, optional - if provided a reference to the adapter object for the scroller instance will be injected in the appropriate scope. If you have multiple scrollers within the same viewport, make sure that every one of them has its unique adapter name.
 
@@ -165,7 +165,14 @@ Some of the properties offered by the adapter can also be accessed directly from
 
 The `expression` can be any angular expression (assignable expression where so specified). All expressions are evaluated once at the time when the scroller is initialized. Changes in the expression value after scroller initialization will have no impact on the scroller behavior.
 
-The assignable expressions will be used by scroller to inject the requested value into the target scope. The scope associated with the viewport (the element marked with the [uiScrollViewport](#uiscrollviewport-directive) directive) will be used as the target scope. If the viewport is not defined (window viewport), the $rootScope will be used as the target scope. Also `Controller As` syntax could be used as an alternative way to specify target controller in assignable expressions.
+The `assignable expressions` will be used by scroller to inject the requested value into the target scope.
+The target scope is being defined in accordance with standard Angular rules (nested scopes and controller As syntax should be taken into account):
+the scroller will traverse its parents (from the ui-scroll element's scope up to the $rootScope) to locate the target scope.
+If the viewport is presented (the element marked with the [uiScrollViewport](#uiscrollviewport-directive) directive),
+then the scope associated with the viewport will be a start point in target scope detecting.
+Angular $parse service is being used in `assignable expressions` implementation.
+
+_Deprecated!_ The format `expression on controller` introduced in v1.5.0 (and deprecated in v1.6.1) can be used to explicitly target the scope associated with the specified controller as the target scope for the injection. In this format `expression` is any angular assignable expression, and `controller` is the name of controller constructor function as specified in the `ng-controller` directive.
 
 ### Datasource
 

demo/insideDirective/insideDirective.html

@@ -22,7 +22,7 @@ <h1 class="page-header page-header-exapmle">Scroller inside the directive</h1>
 		</div>
 
 		<div ng-controller="mainController">
-			<div ng-if="true">
+			<div ng-if="show">
 				<my-dir></my-dir>
 			</div>
 		</div>

dist/ui-scroll.js

@@ -1,22 +1,6 @@
-function findCtrl(scope, ctrl) {
-  if (!scope) {
-    return;
-  }
-  if (scope.hasOwnProperty(ctrl) && Object.getPrototypeOf(scope[ctrl]).constructor.hasOwnProperty('$inject')) {
-    return scope[ctrl];
-  }
-  return findCtrl(scope.$parent, ctrl);
-}
-
-function assignAttr(attr, scope, element) {
-  if (!attr || !(attr = attr.replace(/^\s+|\s+$/gm, ''))) {
-    return;
-  }
-
+function getCtrlOnData(attr, element) {
   let onSyntax = attr.match(/^(.+)(\s+on\s+)(.+)?/);
-  let asSyntax = attr.match(/^([^.]+)\.(.+)?/);
-
-  if (onSyntax && onSyntax.length === 4) { // controller on (backward compatibility), deprecated since v1.6.1
+  if (onSyntax && onSyntax.length === 4) {
     window.console.warn('Angular ui-scroll adapter assignment warning. "Controller On" syntax has been deprecated since ui-scroll v1.6.1.');
     let ctrl = onSyntax[3];
     let tail = onSyntax[1];
@@ -34,61 +18,56 @@ function assignAttr(attr, scope, element) {
     }
     throw new Error('Angular ui-scroll adapter assignment error. Failed to locate target controller "' + ctrl + '" to inject "' + tail + '"');
   }
-  else if (asSyntax && asSyntax.length === 3) { // controller as
-    let ctrl = asSyntax[1];
-    let tail = asSyntax[2];
-    let foundCtrl = findCtrl(scope, ctrl);
-    if (foundCtrl) {
-      return {
-        target: foundCtrl,
-        source: tail
-      };
-    }
-  }
-
-  return {
-    target: scope,
-    source: attr
-  };
 }
 
 class Adapter {
 
-  constructor(viewport, buffer, adjustBuffer, reload, $attr, $parse, element) {
+  constructor(viewport, buffer, adjustBuffer, reload, $attr, $parse, element, $scope) {
     this.viewport = viewport;
     this.buffer = buffer;
     this.adjustBuffer = adjustBuffer;
     this.reload = reload;
 
-    this.publicContext = {};
-    this.assignAdapter($attr, $parse, element);
-    this.generatePublicContext($attr, $parse, element);
-
     this.isLoading = false;
     this.disabled = false;
-  }
 
-  assignAdapter($attr, $parse, element) {
-    let data = assignAttr($attr.adapter, this.viewport.getScope(), element);
+    const viewportScope = viewport.getScope();
+    this.startScope = viewportScope.$parent ? viewportScope : $scope;
+
+    this.publicContext = {};
+    this.assignAdapter($attr.adapter, $parse, element);
+    this.generatePublicContext($attr, $parse);
+  }
 
-    if (data) {
-      try {
-        $parse(data.source).assign(data.target, {});
-        let adapterOnScope = $parse(data.source)(data.target);
+  assignAdapter(adapterAttr, $parse, element) {
+    if (!adapterAttr || !(adapterAttr = adapterAttr.replace(/^\s+|\s+$/gm, ''))) {
+      return;
+    }
+    let ctrlOnData = getCtrlOnData(adapterAttr, element);
+    let adapterOnScope;
 
-        angular.extend(adapterOnScope, this.publicContext);
-        this.publicContext = adapterOnScope;
+    try {
+      if (ctrlOnData) { // "Controller On", deprecated since v1.6.1
+        $parse(ctrlOnData.source).assign(ctrlOnData.target, {});
+        adapterOnScope = $parse(ctrlOnData.source)(ctrlOnData.target);
       }
-      catch (error) {
-        error.message = `Angular ui-scroll Adapter assignment exception.\n` +
-          `Can't parse "${$attr.adapter}" expression.\n` +
-          error.message;
-        throw error;
+      else {
+        $parse(adapterAttr).assign(this.startScope, {});
+        adapterOnScope = $parse(adapterAttr)(this.startScope);
       }
     }
+    catch (error) {
+      error.message = `Angular ui-scroll Adapter assignment exception.\n` +
+        `Can't parse "${adapterAttr}" expression.\n` +
+        error.message;
+      throw error;
+    }
+
+    angular.extend(adapterOnScope, this.publicContext);
+    this.publicContext = adapterOnScope;
   }
 
-  generatePublicContext($attr, $parse, element) {
+  generatePublicContext($attr, $parse) {
     // these methods will be accessible out of ui-scroll via user defined adapter
     const publicMethods = ['reload', 'applyUpdates', 'append', 'prepend', 'isBOF', 'isEOF', 'isEmpty'];
     for (let i = publicMethods.length - 1; i >= 0; i--) {
@@ -98,19 +77,15 @@ class Adapter {
     // these read-only props will be accessible out of ui-scroll via user defined adapter
     const publicProps = ['isLoading', 'topVisible', 'topVisibleElement', 'topVisibleScope'];
     for (let i = publicProps.length - 1; i >= 0; i--) {
-      let property, assignProp;
-      let data = assignAttr($attr[publicProps[i]], this.viewport.getScope(), element);
-      if (data) {
-        assignProp = $parse(data.source).assign;
-      }
+      let property, attr = $attr[publicProps[i]];
       Object.defineProperty(this, publicProps[i], {
         get: () => property,
         set: (value) => {
           property = value;
-          if (assignProp) {
-            assignProp(data.target, value);
-          }
           this.publicContext[publicProps[i]] = value;
+          if (attr) {
+            $parse(attr).assign(this.startScope, value);
+          }
         }
       });
     }

dist/ui-scroll.js.map

@@ -81,7 +81,7 @@ angular.module('ui.scroll', [])
         let elementRoutines = new ElementRoutines($injector, $q);
         let buffer = new ScrollBuffer(elementRoutines, bufferSize);
         let viewport = new Viewport(elementRoutines, buffer, element, viewportController, $rootScope, padding);
-        let adapter = new Adapter(viewport, buffer, adjustBuffer, reload, $attr, $parse, element);
+        let adapter = new Adapter(viewport, buffer, adjustBuffer, reload, $attr, $parse, element, $scope);
 
         if (viewportController) {
           viewportController.adapter = adapter;