Clarify failure message when testing existence.

diff --git a/GLOBALS.mjs b/GLOBALS.mjs
index fee53333cca51a42351a32ac6144a820344f9c7a..0ed94e809550dd3dfe190319bd9a770892a5c251 100644 (file)
--- a/GLOBALS.mjs
+++ b/GLOBALS.mjs
@@ -60,7 +60,8 @@ export const assert = {
        },
        exists: (a) => {
                if (a == null) {
-                       throw new Error(`argument is ${typeof a}`)
+                       const type = /^[aeiou]/i.test(typeof a) ? `an ${typeof a}` : `a ${typeof a}`
+                       throw new Error(`argument exists and is ${type}`)
                }
                return a != null
        },