fixed typos

Author: bennobuilder

docs/packages/core/features/collection/Introduction.md

@@ -269,8 +269,8 @@ which gives us much more freedom in configuring them.
 <br/>
 
 #### `key`
-The name/key is an optional property that is used to identify a specific Collection.
-Such key is pretty useful during debug sessions or if we persist our Collection,
+The `key/name` is an optional property that is used to identify the Collection later.
+Such `key` is pretty useful during debug sessions or if we [persist](./Methods.md#persist) our Collection,
 it automatically uses the Collection `key` as persist key.
 We recommend giving each Collection a unique `key`, since it has only advantages.
 ```ts

docs/packages/core/features/collection/group/Introduction.md

@@ -103,7 +103,56 @@ MY_GROUP.value; // Returns '[1, 2, 3]'
 ```
 
 ### `config`
-TODO
+
+Beside the initial îtemKeys a `Collection` takes an optional configuration object.
+```ts
+const MY_GROUP = MY_COLLECTION.createGroup([1, 2, 3], {
+    key: "myGroup",
+});
+```
+Here is a Typescript Interface for quick reference. However,
+each property is explained in more detail below.
+```ts
+export interface GroupConfigInterface {
+    key?: GroupKey;
+    isPlaceholder?: boolean;
+}
+```
+
+<br/>
+
+#### `key`
+The `key/name` is an optional property that is used to identify the Group later.
+Such `key` is pretty useful during debug sessions or if we [persist](../../state/Methods.md#persist) our Group,
+it automatically uses the Group `key` as persist key.
+We recommend giving each Collection a unique `key`, since it has only advantages.
+```ts
+const MY_GROUP = MY_COLLECTION.createGroup([1, 2, 3], {
+    key: "myKey"
+});
+```
+
+<br/>
+
+#### `isPlaceholder`
+
+:::warning
+
+This property is mainly thought for internal use.
+
+:::
+
+With `isPlaceholder` we tell our Group that it's a placeholder.
+Often Groups are `placeholder` when AgileTs needs to hold a reference to it,
+although the Group doesn't official exists and hasn't been instantiated yet.
+```ts
+const MY_STATE = App.createState("myInitialValue", {
+    isPlaceholder: true
+});
+
+MY_STATE.exists(); // false
+```
+
 
 ## 🟦 Typescript
 

docs/packages/core/features/state/Introduction.md

@@ -95,9 +95,9 @@ export interface StateConfigInterface {
 <br/>
 
 #### `key`
-The `key/name` is an optional property that serves to identify a State later.
-A key is pretty useful during debug sessions or if we [persist](./Methods.md#persist) our State.
-Then, it automatically uses the `key` as persist-key, and we don't have to pass a separate one.
+The `key/name` is an optional property that is used to identify the State later.
+Such `key` is pretty useful during debug sessions or if we [persist](./Methods.md#persist) our State,
+it automatically uses the State `key` as persist key.
 We recommend giving each State a unique `key`, since it has only advantages.
 ```ts
 const MY_STATE = App.createState("myInitialValue", {
@@ -109,9 +109,9 @@ const MY_STATE = App.createState("myInitialValue", {
 
 #### `dependents`
 
-:::info
+:::warning
 
-Mainly used internally and has properly no use for you.
+This property is mainly thought for internal use.
 
 :::
 
@@ -128,9 +128,9 @@ const MY_STATE = App.createState("myInitialValue", {
 
 #### `isPlaceholder`
 
-:::info
+:::warning
 
-Mainly used internally and has properly no use for you.
+This property is mainly thought for internal use.
 
 :::