diff --git a/lib/types.luau b/lib/types.luau
index ced3e99..0c9a6fd 100644
--- a/lib/types.luau
+++ b/lib/types.luau
@@ -15,4 +15,6 @@ export type opts = {
 
 export type model = {Instance}
 
+export type callbackFunction = (file: string, opts: opts) -> string | boolean
+
 return types
\ No newline at end of file
diff --git a/tests/tests.luau b/tests/tests.luau
index bcf3aaf..d6f7063 100644
--- a/tests/tests.luau
+++ b/tests/tests.luau
@@ -5,7 +5,7 @@ local compression = require("../lib/compression")
 local types = require("../lib/types")
 
 
-function testFolder(callback: (file: string, opts: types.opts) -> string | boolean, opts: types.opts, folderPath: string): {boolean}
+function testFolder(callback: types.callbackFunction, opts: types.opts, folderPath: string): {boolean}
     local results = {}
     local folder = fs.readDir(folderPath)
     for _, file in pairs(folder) do