refactor: move angular source to /packages rather than modules/@angular

packages/common/src/directives/ng_plural.ts

@@ -0,0 +1,109 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import {Attribute, Directive, Host, Input, TemplateRef, ViewContainerRef} from '@angular/core';
+
+import {NgLocalization, getPluralCategory} from '../localization';
+
+import {SwitchView} from './ng_switch';
+
+
+/**
+ * @ngModule CommonModule
+ *
+ * @whatItDoes Adds / removes DOM sub-trees based on a numeric value. Tailored for pluralization.
+ *
+ * @howToUse
+ * ```
+ * <some-element [ngPlural]="value">
+ *   <ng-template ngPluralCase="=0">there is nothing</ng-template>
+ *   <ng-template ngPluralCase="=1">there is one</ng-template>
+ *   <ng-template ngPluralCase="few">there are a few</ng-template>
+ * </some-element>
+ * ```
+ *
+ * @description
+ *
+ * Displays DOM sub-trees that match the switch expression value, or failing that, DOM sub-trees
+ * that match the switch expression's pluralization category.
+ *
+ * To use this directive you must provide a container element that sets the `[ngPlural]` attribute
+ * to a switch expression. Inner elements with a `[ngPluralCase]` will display based on their
+ * expression:
+ * - if `[ngPluralCase]` is set to a value starting with `=`, it will only display if the value
+ *   matches the switch expression exactly,
+ * - otherwise, the view will be treated as a "category match", and will only display if exact
+ *   value matches aren't found and the value maps to its category for the defined locale.
+ *
+ * See http://cldr.unicode.org/index/cldr-spec/plural-rules
+ *
+ * @experimental
+ */
+@Directive({selector: '[ngPlural]'})
+export class NgPlural {
+  private _switchValue: number;
+  private _activeView: SwitchView;
+  private _caseViews: {[k: string]: SwitchView} = {};
+
+  constructor(private _localization: NgLocalization) {}
+
+  @Input()
+  set ngPlural(value: number) {
+    this._switchValue = value;
+    this._updateView();
+  }
+
+  addCase(value: string, switchView: SwitchView): void { this._caseViews[value] = switchView; }
+
+  private _updateView(): void {
+    this._clearViews();
+
+    const cases = Object.keys(this._caseViews);
+    const key = getPluralCategory(this._switchValue, cases, this._localization);
+    this._activateView(this._caseViews[key]);
+  }
+
+  private _clearViews() {
+    if (this._activeView) this._activeView.destroy();
+  }
+
+  private _activateView(view: SwitchView) {
+    if (view) {
+      this._activeView = view;
+      this._activeView.create();
+    }
+  }
+}
+
+/**
+ * @ngModule CommonModule
+ *
+ * @whatItDoes Creates a view that will be added/removed from the parent {@link NgPlural} when the
+ *             given expression matches the plural expression according to CLDR rules.
+ *
+ * @howToUse
+ * ```
+ * <some-element [ngPlural]="value">
+ *   <ng-template ngPluralCase="=0">...</ng-template>
+ *   <ng-template ngPluralCase="other">...</ng-template>
+ * </some-element>
+ *```
+ *
+ * See {@link NgPlural} for more details and example.
+ *
+ * @experimental
+ */
+@Directive({selector: '[ngPluralCase]'})
+export class NgPluralCase {
+  constructor(
+      @Attribute('ngPluralCase') public value: string, template: TemplateRef<Object>,
+      viewContainer: ViewContainerRef, @Host() ngPlural: NgPlural) {
+    const isANumber: boolean = !isNaN(Number(value));
+    ngPlural.addCase(isANumber ? `=${value}` : value, new SwitchView(viewContainer, template));
+  }
+}