create stable command parser

bot/commands/iteminfo.ts

@@ -1,8 +1,9 @@
 import { Command, sendMessage } from ".";
 import items from "../items";
+import parseCommandArgs from "../lib/parseCommandArgs";
 
 export default new Command('iteminfo', ['iteminfo', 'itemhelp', 'info'], [], async msg => {
-  const messagequery = msg.messageText.trim().split(' ').slice(1).join(' ');
+  const messagequery = parseCommandArgs(msg.messageText).join(' ');
   if (!messagequery) { await sendMessage('Please specify an item you would like to get info about', msg.messageId); return; };
   const selection = items.get(messagequery.toLowerCase());
   if (!selection) { await sendMessage(`'${messagequery}' is not an item`, msg.messageId); return; };

bot/items/blaster.ts

@@ -1,5 +1,6 @@
 import { Item } from ".";
 import { sendMessage } from "../commands";
+import parseCommandArgs from "../lib/parseCommandArgs";
 import { timeout } from "../lib/timeout";
 import { User } from "../user";
 
@@ -7,8 +8,7 @@ export default new Item('blaster', 'Blaster', 's',
   'Times a specific person out for 60 seconds',
   ['blaster', 'blast'], ['moderator:manage:banned_users'],
   async (msg, user) => {
-    const slicecount = msg.messageText.startsWith('!use') ? 2 : 1;
-    const messagequery = msg.messageText.trim().split(' ').slice(slicecount);
+    const messagequery = parseCommandArgs(msg.messageText);
     if (!messagequery[0]) { await sendMessage('Please specify a target'); return; };
     const target = await User.initUsername(messagequery[0].toLowerCase());
     if (!target) { await sendMessage(`${messagequery[0]} doesn't exist`); return; };

bot/lib/parseCommandArgs.ts

@@ -0,0 +1,9 @@
+import { commandPrefix } from "..";
+
+/** Helper function to extract arguments from commands */
+export default function parseCommandArgs(input: string) {
+  const a = input.slice(commandPrefix.length);
+  const sliceLength = a.startsWith('use') ? 2 : 1;
+  const b = a.trim().split(' ').slice(sliceLength);
+  return b;
+};