diff --git a/lib/index.mjs b/lib/index.mjs
index 4358dab..3f91bac 100644
--- a/lib/index.mjs
+++ b/lib/index.mjs
@@ -108,7 +108,7 @@ export function createResolve (defaults) {
 }
 
 export function interopDefault (sourceModule) {
-  if (!(sourceModule && 'default' in sourceModule)) {
+  if (!isObject(sourceModule) || !('default' in sourceModule)) {
     return sourceModule
   }
   const newModule = sourceModule.default
@@ -314,3 +314,7 @@ function _perr (_err) {
   Error.captureStackTrace(err, _pcall)
   return Promise.reject(err)
 }
+
+function isObject (val) {
+  return val !== null && typeof val === 'object'
+}
diff --git a/test/interop.test.mjs b/test/interop.test.mjs
index 404e4de..2e13d93 100644
--- a/test/interop.test.mjs
+++ b/test/interop.test.mjs
@@ -4,6 +4,8 @@ import { interopDefault } from '../lib/index.mjs'
 const tests = [
   [{}, {}],
   [{ default: {} }, {}],
+  [true, true],
+  [[1, 2, 3], [1, 2, 3]],
   [{ default: { x: 2 } }, { x: 2 }],
   [{ named: 2 }, { named: 2 }],
   [{ named: 2, default: {} }, { named: 2 }],
@@ -15,8 +17,10 @@ describe('interopDefault', () => {
     it(JSON.stringify(input), () => {
       const interop = interopDefault(input)
       expect(interop).to.deep.equal(result)
-      if ('default' in input) {
+      if (typeof input === 'object' && 'default' in input) {
         expect(interop.default).to.deep.equal(result)
+      } else {
+        expect(interop).to.deep.equal(result)
       }
     })
   }