add message delete on size limit

src/modules/messages.ts

@@ -1,10 +1,13 @@
 import { ref } from 'vue';
 import { RenderMessage, Annotation } from "@/types/message/index";
 
+const messagesKey = "CRIMATA_MESSAGES";
+const sizeLimit = 200;
+
+// list of messages where the first item is the oldest message.
 const messages = ref(new Map());
 
-const messagesKey = "CRIMATA_MESSAGES";
-
+// get stored messages.
 const messagesString = window.localStorage.getItem(messagesKey);
 
 if (messagesString) {
@@ -14,9 +17,22 @@ if (messagesString) {
   messages.value = new Map(Object.entries(parsed));
 }
 
+// utility function to remove oldest message from the messages map. 
+function deleteOldest() { 
+   // create array of map keys and get the key of the oldest message.
+   const lastKey = Array.from(messages.value.keys()).shift();
+
+   messages.value.delete(lastKey);
+}
+
 export default function useMessages() {
 
-    const addMessage = (m: RenderMessage) => messages.value.set(m.uid, m);
+    const addMessage = (m: RenderMessage) => {
+      // check for message limit before setting a new message.
+      if (messages.value.size >= sizeLimit) deleteOldest();
+      
+      messages.value.set(m.uid, m);
+    }
 
     const updateMessage = (m: Annotation) => {
         // update message if in the map.