item transfer, item to buy other items, item income, unbuyable items

commands/common/common.ts

@@ -0,0 +1,16 @@
+import { get_item } from "../../db";
+
+//if return string, that is error message
+export async function items_string_to_items(items_string: string): Promise<[string, number][] | string> {
+  let items = [];
+  for (const item of items_string.split("|")) {
+    const parts = item.split(",");
+    if (parts.length !== 2) return "Incorrect items format, must be `name,quantity|name,quantity`, etc";
+    const quantity = Number(parts[1]);
+    if (isNaN(quantity) || Math.floor(quantity) !== quantity) return "Item quantity was not an integer";
+    if (!await get_item(parts[0])) return `Item \`${parts[0].replaceAll("`", "\\`")}\` does not exist`;
+    items.push([parts[0], quantity]);
+  }
+  return items;
+}
+