diff --git a/Makefile b/Makefile
index 4b8c1f5..e64d1d7 100644
--- a/Makefile
+++ b/Makefile
@@ -16,7 +16,7 @@ dist/test/integration/foobar_magic dist/test/integration/png_magic dist/test/int
 
 package: dist/index.js dist/libmagic.LICENSE
 
-dist/index.js: $(ts_files) dist/libmagic-wrapper.js
+dist/index.js: $(ts_files) dist/libmagic-wrapper.js dist/LibmagicModule.d.ts dist/StdioOverrideFunction.d.ts
 	npx tsc -d
 
 dist/libmagic-wrapper.js: src/libmagic-wrapper.c dist/magic.mgc dist/libmagic.so dist/libmagic-wrapper.d.ts
@@ -31,8 +31,14 @@ dist/libmagic-wrapper.js: src/libmagic-wrapper.c dist/magic.mgc dist/libmagic.so
 	-o dist/libmagic-wrapper.js \
 	src/libmagic-wrapper.c
 
-dist/libmagic-wrapper.d.ts: types/libmagic-wrapper.d.ts
-	cp types/libmagic-wrapper.d.ts dist/libmagic-wrapper.d.ts
+dist/libmagic-wrapper.d.ts: src/libmagic-wrapper.d.ts
+	cp src/libmagic-wrapper.d.ts dist/libmagic-wrapper.d.ts
+
+dist/LibmagicModule.d.ts: src/LibmagicModule.d.ts
+	cp src/LibmagicModule.d.ts dist/LibmagicModule.d.ts
+
+dist/StdioOverrideFunction.d.ts: src/StdioOverrideFunction.d.ts
+	cp src/StdioOverrideFunction.d.ts dist/StdioOverrideFunction.d.ts
 
 dist/libmagic.LICENSE: vendor/file/COPYING
 	cp vendor/file/COPYING dist/libmagic.LICENSE
diff --git a/dist/.npmignore b/dist/.npmignore
index 160d5c2..cbddbe0 100644
--- a/dist/.npmignore
+++ b/dist/.npmignore
@@ -2,3 +2,5 @@
 !index.*
 !*LICENSE
 !libmagic-wrapper.*
+!LibmagicModule.d.ts
+!StdioOverrideFunction.d.ts
diff --git a/types/LibmagicModule.d.ts b/src/LibmagicModule.d.ts
similarity index 62%
rename from types/LibmagicModule.d.ts
rename to src/LibmagicModule.d.ts
index 9902a68..5bbbe51 100644
--- a/types/LibmagicModule.d.ts
+++ b/src/LibmagicModule.d.ts
@@ -1,7 +1,4 @@
-type StdioOverrideFunction = (
-  stdioName: "stdout" | "stderr",
-  text: string,
-) => void;
+import StdioOverrideFunction from "./StdioOverrideFunction";
 
 interface LibmagicModule extends EmscriptenModule {
   FS: typeof FS;
@@ -9,3 +6,5 @@ interface LibmagicModule extends EmscriptenModule {
   cwrap: typeof cwrap;
   printOverride: StdioOverrideFunction;
 }
+
+export default LibmagicModule;
diff --git a/src/StdioOverrideFunction.d.ts b/src/StdioOverrideFunction.d.ts
new file mode 100644
index 0000000..d759a9f
--- /dev/null
+++ b/src/StdioOverrideFunction.d.ts
@@ -0,0 +1,6 @@
+type StdioOverrideFunction = (
+  stdioName: "stdout" | "stderr",
+  text: string,
+) => void;
+
+export default StdioOverrideFunction;
diff --git a/src/index.ts b/src/index.ts
index 83740dc..0ee32f0 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,4 +1,7 @@
-import libmagicFactory from "../dist/libmagic-wrapper";
+import libmagicFactory from "./libmagic-wrapper";
+import LibmagicModule from "./LibmagicModule";
+import StdioOverrideFunction from "./StdioOverrideFunction";
+export type * as StdioOverrideFunction from "./StdioOverrideFunction";
 
 declare function wrappedDetect(bufPointer: number, bufLength: number): string;
 
diff --git a/types/libmagic-wrapper.d.ts b/src/libmagic-wrapper.d.ts
similarity index 64%
rename from types/libmagic-wrapper.d.ts
rename to src/libmagic-wrapper.d.ts
index ac06de7..d087dde 100644
--- a/types/libmagic-wrapper.d.ts
+++ b/src/libmagic-wrapper.d.ts
@@ -1,2 +1,4 @@
+import LibmagicModule from "./LibmagicModule";
+
 declare const factory: EmscriptenModuleFactory<LibmagicModule>;
 export default factory;
diff --git a/src/test/integration/index.ts b/src/test/integration/index.ts
index 8ff4965..cb93c71 100644
--- a/src/test/integration/index.ts
+++ b/src/test/integration/index.ts
@@ -3,6 +3,7 @@ import * as path from "path";
 import { glob } from "glob";
 import { cases } from "./data";
 import { WASMagic, WASMagicFlags } from "../../index";
+import StdioOverrideFunction from "../../StdioOverrideFunction";
 
 describe("WASMagic", () => {
   describe("Default magic file", () => {
@@ -49,6 +50,24 @@ describe("WASMagic", () => {
         expect(magicText.detect(fileBuf)).toBe(expectedText);
       },
     );
+
+    test("WASMagic throws when it fails to load", async () => {
+      let err: Error | undefined;
+      try {
+        await WASMagic.create({
+          loadDefaultMagicfile: false,
+          magicFiles: [
+            // To force a loading failure
+            Buffer.from("FOOOOOOOBAR"),
+          ],
+        });
+      } catch (_err) {
+        err = _err as Error;
+      }
+
+      expect(err).toBeInstanceOf(Error);
+      expect(err?.message.startsWith("WASMagic Load Error: ")).toBe(true);
+    });
   });
 
   describe("Specified foobar custom magic file, with default magic file", () => {
@@ -112,4 +131,36 @@ Some made up stuff
       },
     );
   });
+
+  describe("StdioOverrideFunction", () => {
+    describe("StdioOverrideFunction fires when WASMagic fails to load", () => {
+      let stdioType: string | undefined;
+      let text: string | undefined;
+      let func: StdioOverrideFunction = (_stdioType, _text) => {
+        stdioType = _stdioType;
+        text = _text;
+      };
+
+      beforeAll(async () => {
+        try {
+          await WASMagic.create({
+            loadDefaultMagicfile: false,
+            magicFiles: [
+              // To force a loading failure
+              Buffer.from("FOOOOOOOBAR"),
+            ],
+            stdio: func,
+          });
+        } catch (_err) {
+          // Ignoring _err
+        }
+      });
+
+      test("stdio is a String", () => expect(typeof stdioType).toBe("string"));
+      test("stdio is stderr", () => expect(stdioType).toBe("stderr"));
+      test("text is a String", () => expect(typeof text).toBe("string"));
+      test("text is a known error", () =>
+        expect(text).toBe("0, 1: Warning: offset `FOOOOOOOBAR' invalid"));
+    });
+  });
 });