Merge branch 'master' into bump-flex-layout

Author: jotatoledo

src/operator-docs/transformation/mapTo.ts

@@ -1,6 +1,53 @@
 import { OperatorDoc } from '../operator.model';
 
 export const mapTo: OperatorDoc = {
-  'name': 'mapTo',
-  'operatorType': 'transformation'
+  name: 'mapTo',
+  operatorType: 'transformation',
+  signature: 'public mapTo(value: any): Observable',
+  parameters: [
+    {
+      name: 'value',
+      type: 'any',
+      attribute: '',
+      description: `The value to map each source value to.`
+    }
+  ],
+  useInteractiveMarbles: true,
+  marbleUrl: 'http://reactivex.io/rxjs/img/mapTo.png',
+  shortDescription: {
+    description: `Emits the given constant value on the output Observable every time the source Observable emits a value.`
+  },
+  walkthrough: {
+    description: `<p>
+        Takes a constant
+        <code>value</code> as argument,
+        and emits that whenever the source Observable emits a value.
+        In other words, ignores the actual source value,
+        and simply uses the emission moment to know when to emit the given
+       <code>value</code>.
+       <p>`
+  },
+  examples: [
+    {
+      name: "Map every click to the string 'Hi'",
+      code: `
+      import { fromEvent } from 'rxjs/observable/fromEvent';
+      import { mapTo } from 'rxjs/operators';
+
+      const clicks = fromEvent(document, 'click');
+      const greetings = clicks.pipe(mapTo('Hi');
+      greetings.subscribe(x => console.log(x));
+      /*
+        Example console output:
+        Hi
+      */
+      `,
+      externalLink: {
+        platform: 'JSBin',
+        url: 'http://jsbin.com/seyibe/embed?js,console,output'
+      }
+    }
+  ],
+  relatedOperators: ['map'],
+  additionalResources: []
 };