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projects/combining-streams/src/lib/exercises/combineLatest/docs/combineLatest.solution.md

 # Combining ongoing Observables - Solution
 
-## Combining ongoing Observables
-
 Combining the http calls with the `combineLatest` operator:
 
 **Component**

projects/combining-streams/src/lib/exercises/forkJoin/docs/forkJoin.theory.md

@@ -2,16 +2,18 @@
 
 This exercise is about combining data coming from multiple HTTP Endpoints into one single set of data.
 Combination operators or creation functions enable us to process emissions 
-from different `Observables` and transform them into a single emission while keeping the original order of events.
+from different `Observables` and transform them into a single emission.
+The resulting value is an array with the last emitted value of all included Observables.
 
 In this very example we will utilize the `forkJoin` operator. 
-On first sight it is a perfect match for combining HTTP Endpoints since it waits until all
+On first sight it is a perfect match for combining HTTP Requests since it waits until all
 combined operators `complete` before emitting a result.
 
 ## Example
 
-The below example showcases a very simple example using the `forkJoin` operator. We make use of the `of` creation function
-since it emits and completes instantly.
+The below example showcases a very simple case using the `forkJoin` operator. 
+We make use of the `of` creation function (passing a singe value), as its emission pattern is very similar to an HTTP request.
+It emits one single value and completes.
 
 ```Typescript
 import {forkJoin, of} from 'rxjs';
@@ -30,6 +32,12 @@ The visual representation of the above example:
 
 ![forkJoin http calls](./assets/images/Reactive-architecture-and-ux-patterns_angular_combination-operators-forkJoin-http_michael-hladky.png)
 
+The gray boxes at the bottom of the operator scope symbolize a cache which stores the last emitted value of each included Observable. 
+
+If any of the sources raises an `error`, it gets forwarded, and the resulting Observable errors. 
+
+![forkJoin error](./assets/images/Reactive-architecture-and-ux-patterns_angular_combination-operators-forkJoin-error_michael-hladky.png)
+
 ## Gotcha(s)!
 
 As stated above, the `forkJoin` creation function waits until every source raises a `complete` event. After that it will return
@@ -43,7 +51,3 @@ As stated above, the `forkJoin` creation function waits until every source raise
  Here you can see how `forkJoin` will never emit any value, because `a$` does not `complete`.
 
 ![forkJoin no emission if not all complete](./assets/images/Reactive-architecture-and-ux-patterns_angular_combination-operators-forkJoin-emit-after-all-complete_michael-hladky.png)
-
-If any of the sources raises an `error`, the result of `forkJoin` will only be the `error`.
-
-![forkJoin error](./assets/images/Reactive-architecture-and-ux-patterns_angular_combination-operators-forkJoin-error_michael-hladky.png)