Merge pull request #219 from natmegs/docs-operator-mergemap

docs(operators): add documentation for operator mergeMap

Author: ashwin-sureshkumar

src/operator-docs/transformation/mergeMap.ts

@@ -1,6 +1,96 @@
 import { OperatorDoc } from '../operator.model';
 
 export const mergeMap: OperatorDoc = {
-  'name': 'mergeMap',
-  'operatorType': 'transformation'
+  name: 'mergeMap',
+  operatorType: 'transformation',
+  signature:
+    'public mergeMap(project: Function, resultSelector?: Function, concurrent?: number): Observable',
+  useInteractiveMarbles: true,
+  parameters: [
+    {
+      name: 'project',
+      type: '(value: T, index: number) => ObservableInput',
+      attribute: '',
+      description: `A function that, when applied to an item emitted by the source Observable, returns
+      an Observable.`
+    },
+    {
+      name: 'resultSelector',
+      type:
+        '(outerValue: T, innerValue: I, outerIndex: number, innerIndex: number) => any',
+      attribute: 'optional',
+      description: `A function to produce the value on the output Observable based on the values and the indices
+        of the source (outer) emission and the inner Observable emission. The arguments passed to this function are:
+        'outerValue': the value that came from the source,
+        'innerValue': the value that came from the projected Observable,
+        'outerIndex': the "index" of the value that came from the source,
+        'innerIndex': the "index" of the value from the projected Observable.`
+    },
+    {
+      name: 'concurrent',
+      type: 'number',
+      attribute: 'optional',
+      description: `Maximum number of input Observables being subscribed to concurrently.`
+    }
+  ],
+  marbleUrl: 'http://reactivex.io/rxjs/img/mergeMap.png',
+  shortDescription: {
+    description: `
+      Projects each source value to an Observable which is merged in the output Observable.
+    `,
+    extras: []
+  },
+  walkthrough: {
+    description: `
+      <p>
+        Returns an Observable that emits items based on applying a function that you supply
+        to each item emitted by the source Observable, where that function returns an Observable,
+        and then merging those resulting Observables and emitting the results of this merger.
+      </p>
+    `
+  },
+  examples: [
+    {
+      name:
+        'Map and flatten each letter to an Observable ticking every 1 second',
+      code: `
+        import { of } from 'rxjs/observable/of';
+        import { interval } from 'rxjs/observable/interval';
+        import { mergeMap, map } from 'rxjs/operators';
+
+        const letters = of('a', 'b', 'c');
+        const result = letters.pipe(
+                            mergeMap(x => {
+                              return interval(1000).pipe(map(i => x+i));
+                            })
+                       );
+        result.subscribe(x => console.log(x));
+
+        // Output
+        "a0"
+        "b0"
+        "c0"
+        "a1"
+        "b1"
+        "c1"
+        "a2"
+        "b2"
+        "c2"
+      `,
+      externalLink: {
+        platform: 'JSBin',
+        url: 'http://jsbin.com/pekelowibe/embed?js,console'
+      }
+    }
+  ],
+  relatedOperators: [
+    'concatMap',
+    'exhaustmap',
+    'merge',
+    'mergeAll',
+    'mergeMapTo',
+    'mergeScan',
+    'switchMap'
+  ],
+  additionalResources: []
 };