docs(combineLatest): Add tip described in issue #143

src/operator-docs/combination/combineLatest.ts

@@ -1,34 +1,42 @@
-import { OperatorDoc } from "../operator.model";
+import { OperatorDoc } from '../operator.model';
 
 export const combineLatest: OperatorDoc = {
-  name: "combineLatest",
-  operatorType: "combination",
+  name: 'combineLatest',
+  operatorType: 'combination',
   signature:
-    "public combineLatest(observables: ...Observable, project: function): Observable",
+    'public combineLatest(observables: ...Observable, project: function): Observable',
   useInteractiveMarbles: true,
   parameters: [
     {
-      name: "other",
-      type: "Observable",
-      attribute: "",
+      name: 'other',
+      type: 'Observable',
+      attribute: '',
       description:
-        "An input Observable to combine with the source Observable. More than one input Observables may be given as argument."
+        'An input Observable to combine with the source Observable. More than one input Observables may be given as argument.'
     },
     {
-      name: "other",
-      type: "function",
-      attribute: "optional",
+      name: 'other',
+      type: 'function',
+      attribute: 'optional',
       description:
-        "An optional function to project the values from the combined latest values into a new value on the output Observable."
+        'An optional function to project the values from the combined latest values into a new value on the output Observable.'
     }
   ],
-  marbleUrl: "http://reactivex.io/rxjs/img/combineLatest.png",
+  marbleUrl: 'http://reactivex.io/rxjs/img/combineLatest.png',
   shortDescription: {
     description: `
       Combines multiple Observables to create an Observable whose values
       are calculated from the latest values of each of its input Observables.
     `,
-    extras: []
+    extras: [
+      {
+        type: 'Tip',
+        text: `
+          Note: combineLatest will only start to emit when all sources have emitted at least once. By adding a default
+           start value to the sources with <a href="/operators#startWith">.startWith</a>, it will activate right away.
+         `
+      }
+    ]
   },
   walkthrough: {
     description: `
@@ -46,7 +54,7 @@ export const combineLatest: OperatorDoc = {
   examples: [
     {
       name:
-        "Dynamically calculate the Body-Mass Index from an Observable of weight and one for height",
+        'Dynamically calculate the Body-Mass Index from an Observable of weight and one for height',
       code: `
         const weight = Rx.Observable.of(70, 72, 76, 79, 75);
         const height = Rx.Observable.of(1.76, 1.77, 1.78);
@@ -60,11 +68,11 @@ export const combineLatest: OperatorDoc = {
         bmi.subscribe(x => console.log('BMI is ' + x));
       `,
       externalLink: {
-        platform: "JSBin",
-        url: "http://jsbin.com/pivowunedu/1/embed?js,console"
+        platform: 'JSBin',
+        url: 'http://jsbin.com/pivowunedu/1/embed?js,console'
       }
     }
   ],
-  relatedOperators: ["combineAll", "merge", "withLatestFrom"],
+  relatedOperators: ['combineAll', 'merge', 'withLatestFrom'],
   additionalResources: []
 };