docs(groupBy): Add documentation for groupBy operator

src/operator-docs/transformation/groupBy.ts

@@ -1,6 +1,134 @@
-import { OperatorDoc } from '../operator.model';
+import { OperatorDoc } from "../operator.model";
 
 export const groupBy: OperatorDoc = {
-  'name': 'groupBy',
-  'operatorType': 'transformation'
+  name: "groupBy",
+  operatorType: "transformation",
+  signature: `
+    public groupBy(keySelector: (value: T) => K,
+                   elementSelector?: ((value: T) => R) | void,
+                   durationSelector?: (grouped: GroupedObservable<K, R>) => Observable<any>,
+                   subjectSelector?: () => Subject<R>)
+          : Observable<any>): OperatorFunction<T, GroupedObservable<K, R>>`,
+  parameters: [
+    {
+      name: "keySelector",
+      type: "(value: T) => K",
+      attribute: "",
+      description: `A function that extracts the key used for grouping for each item.`
+    },
+    {
+      name: "elementSelector",
+      type: "((value: T) => R) | void",
+      attribute: "optional",
+      description: `A function that extracts the emitted element for each item. Default is identity function.`
+    },
+    {
+      name: "durationSelector",
+      type: "(grouped: GroupedObservable<K, R>) => Observable<any>",
+      attribute: "optional",
+      description: `A function that returns an Observable to determine how long each group should exist.`
+    },
+    {
+      name: "subjectSelector",
+      type: "() => Subject<R>",
+      attribute: "optional",
+      description: ``
+    }
+  ],
+  marbleUrl: "http://reactivex.io/rxjs/img/groupBy.png",
+  shortDescription: {
+    description: `
+      Group, according to a specified key, elements from items emitted by an Observable,
+      and emit these grouped items as GroupedObservables, one GroupedObservable per group.
+    `,
+    extras: []
+  },
+  walkthrough: {
+    description: `
+    <p>When the Observable emits an item, a key is computed for this item with the keySelector function.</p>
+
+    <p>If a GroupedObservable for this key exists, this GroupedObservable emits. Elsewhere, a new
+    GroupedObservable for this key is created and emits.</p>
+
+    <p>A GroupedObservable represents values belonging to the same group represented by a common key.
+    The common key is available as the key field of a GroupedObservable instance.</p>
+
+    <p>The elements emitted by GroupedObservables are by default the items emitted by the Observable,
+    or elements returned by the elementSelector function.
+    `
+  },
+  examples: [
+    {
+      name: "Group objects by id and return as array",
+      code: `
+        interface Obj {
+          id: number;
+          name: string;
+        }
+        Rx.Observable.of<Obj>({id: 1, name: 'aze1'},
+                              {id: 2, name: 'sf2'},
+                              {id: 2, name: 'dg2'},
+                              {id: 1, name: 'erg1'},
+                              {id: 1, name: 'df1'},
+                              {id: 2, name: 'sfqfb2'},
+                              {id: 3, name: 'qfs3'},
+                              {id: 2, name: 'qsgqsfg2'})
+          .groupBy(p => p.id)
+          .flatMap( (group$) => group$.reduce((acc, cur) => [...acc, cur], []))
+          .subscribe(p => console.log(p));
+        /*
+          Output:
+          [ { id: 1, name: 'aze1' },
+            { id: 1, name: 'erg1' },
+            { id: 1, name: 'df1' } ]
+
+          [ { id: 2, name: 'sf2' },
+            { id: 2, name: 'dg2' },
+            { id: 2, name: 'sfqfb2' },
+            { id: 2, name: 'qsgqsfg2' } ]
+
+          [ { id: 3, name: 'qfs3' } ]
+        */
+        `,
+      externalLink: {
+        platform: "JSBin",
+        url: "http://jsbin.com/linekelumo/1/embed?js,console"
+      }
+    },
+    {
+      name: "Pivot data on the id field",
+      code: `
+      interface Obj {
+        id: number;
+        name: string;
+      }
+      Rx.Observable.of<Obj>({id: 1, name: 'aze1'},
+                            {id: 2, name: 'sf2'},
+                            {id: 2, name: 'dg2'},
+                            {id: 1, name: 'erg1'},
+                            {id: 1, name: 'df1'},
+                            {id: 2, name: 'sfqfb2'},
+                            {id: 3, name: 'qfs1'},
+                            {id: 2, name: 'qsgqsfg2'})
+        .groupBy(p => p.id, p => p.name)
+        .flatMap( (group$) => group$.reduce((acc, cur) => [...acc, cur], ["" + group$.key]))
+        .map(arr => ({'id': parseInt(arr[0]), 'values': arr.slice(1)}))
+        .subscribe(p => console.log(p));
+      /*
+        Output:
+        { id: 1, values: [ 'aze1', 'erg1', 'df1' ] }
+
+        { id: 2, values: [ 'sf2', 'dg2', 'sfqfb2', 'qsgqsfg2' ] }
+
+        { id: 3, values: [ 'qfs1' ] }
+      */
+        `,
+      externalLink: {
+        platform: "JSBin",
+        url: "http://jsbin.com/racikizeji/embed?js,console"
+      }
+    }
+  ],
+  relatedOperators: [],
+  additionalResources: []
 };