Merge pull request #39 from sern-handler/Murtatrxx-patch-1

refactor: Update services.md

docs/guide/walkthrough/services.md

@@ -2,11 +2,12 @@
 sidebar_position: 6
 ---
 
+# Services
+
 :::tip
 This is version 3 api only!!
 :::
 
-# Services
 
 :::tip
 TLDR: The direct upgrade to useContainer. if you set up a bot with create-bot, check dependencies.d.ts. 
@@ -46,16 +47,110 @@ export default commandModule({
     }
    // 
 })
+```
+
+
+import Tabs from '@theme/Tabs';
+import TabItem from '@theme/TabItem';
+
+
+## Safety
+- Services cannot be called in other services while makeDependencies is forming.
+
+<Tabs>
+
+<TabItem value="good" label="A good example">
+
+Lets pass a logger into our database.
+```ts title="index.ts" showLineNumbers
+await makeDependencies({ 
+    build: root => root
+        //Overriding the default logger provided.
+        .upsert({ '@sern/logger': single(() => new Logger()) })
+
+        // Wiring our logger into the database.
+        .add(ctx =>  {
+            return { database: single(() => new Database(ctx['sern/logger']))) }
+        })
+})
+```
+</TabItem>
+
+<TabItem value="bad" label="Don't do this">
+
+```ts title="index.ts" showLineNumbers
+await makeDependencies({ 
+    build: root => root
+        //Overriding the default logger provided.
+        .upsert({ '@sern/logger': single(() => new Logger()) })
+
+        // Wiring our logger into the database.
+        // We wire our database incorrectly. Logger should be passed INTO the constructor
+        .add({ database: single(() => new Database()) })
+})
+```
+
+```ts title="index.ts" showLineNumbers
+import { Service, makeDependencies } from '@sern/handler';
+
+//Calling Service prematurely!
+const logger = Service('@sern/logger');
 
+class Database {
+
+    constructor() {
+        this.logger = logger
+    }
+}
 ```
-## Safety 
+This is a code smell anyway. It breaks encapsulation and defeats the purpose of wiring dependencies
+</TabItem>
+</Tabs>
+
+- Services can only be used after sern has made dependencies. 
+    - Calling a service before will crash your application. 
+- Services can be safely used outside of commandModules. 
+    - Be careful to not cause too many side effects.
+
+
+
+- You will need to wire dependencies together.
+
+<Tabs>
+<TabItem value="good" label="A good example">
+
+```ts title="index.ts" showLineNumbers
+await makeDependencies(...pass your options here)
+```
+```ts title="commands/ping.ts" showLineNumbers
+// This is guaranteed to be defined if configured correctly
+import { Service } from '@sern/handler';
+const client = Service('@sern/client');
+```
+
+</TabItem>
+
+<TabItem value="bad" label="Don't do this">
+
+```ts title="index.ts" showLineNumbers
+import { Service, makeDependencies } from '@sern/handler';
+/* DON'T USE SERVICES BEFORE CALLING makeDependencies */
+const logger = Service('@sern/logger');
+
+await makeDependencies()
+```
+
+</TabItem>
+
+</Tabs>
+
 - Services can only be used after sern has made dependencies. 
     - Calling a service before will crash your application. 
-- Services can be safely used outside of commandModules.
+- Services can be safely used outside of commandModules. 
     - Be careful to not cause too many side effects.
 
 
-## Related api 
+## Related api
 - use `Service` for single dependency.
 - use `Services` for multiple dependencies.