Add a chatMessageTextOnly variable

This is ideally suitable for Text-To-Speech messages and the like.
It will filter out any URLs, and any emotes, so only the text from the
chat message remains.

I also have no clue how to properly get a firebot development
environment setup (darn you font awesome, what am I doing wrong?), but
it seems to be fully functional on twitch with every scenariou I could
throw at it.

src/backend/variables/builtin/twitch/chat/message/chat-message-text-only.ts

@@ -0,0 +1,36 @@
+import { ReplaceVariable } from "../../../../../../types/variables";
+import { EffectTrigger } from "../../../../../../shared/effect-constants";
+import { OutputDataType, VariableCategory } from "../../../../../../shared/variable-constants";
+
+const triggers = {};
+triggers[EffectTrigger.MANUAL] = true;
+triggers[EffectTrigger.COMMAND] = true;
+triggers[EffectTrigger.EVENT] = [
+    "twitch:chat-message",
+    "twitch:first-time-chat",
+    "firebot:highlight-message",
+    "twitch:viewer-arrived"
+];
+
+const model: ReplaceVariable = {
+    definition: {
+        handle: "chatMessageTextOnly",
+        description: "Outputs the chat message from the associated command or event, with any emotes or URLs trimmed out",
+        triggers: triggers,
+        categories: [VariableCategory.COMMON, VariableCategory.TRIGGER],
+        possibleDataOutput: [OutputDataType.TEXT]
+    },
+    evaluator: (trigger) => {
+        let messageParts = [];
+        if (trigger.type === EffectTrigger.COMMAND) {
+            messageParts = trigger.metadata.chatMessage.parts;
+        } else if (trigger.type === EffectTrigger.EVENT) {
+            messageParts = trigger.metadata.eventData.chatMessage.parts;
+        }
+
+        const textParts = messageParts.filter(p => p.type === "text").map(p => p.text);
+        return textParts.join(" ").trim();
+    }
+};
+
+export default model;

src/backend/variables/builtin/twitch/chat/message/index.ts

@@ -1,6 +1,7 @@
 import chatMessageAnimatedEmoteUrls from './chat-message-animated-emote-urls';
 import chatMessageEmoteNames from './chat-message-emote-names';
 import chatMessageEmoteUrls from './chat-message-emote-urls';
+import chatMessageTextOnly from './chat-message-text-only';
 import chatMessage from './chat-message';
 import chatColor from './chat-user-color';
 
@@ -13,6 +14,7 @@ export default [
     chatMessageAnimatedEmoteUrls,
     chatMessageEmoteNames,
     chatMessageEmoteUrls,
+    chatMessageTextOnly,
     chatMessage,
 
     chatColor,