diff --git a/src/esmockModule.js b/src/esmockModule.js
index 3adc68d..7ab4524 100644
--- a/src/esmockModule.js
+++ b/src/esmockModule.js
@@ -2,6 +2,7 @@ import fs from 'fs'
 import resolvewith from 'resolvewithplus'
 import esmockErr from './esmockErr.js'
 import esmockIsESMRe from './esmockIsESMRe.js'
+import esmockResolver from './esmockResolver.js'
 
 import {
   esmockTreeIdSet,
@@ -116,7 +117,8 @@ const esmockModuleId = async (parent, treeid, defs, ids, opt, mocks, id) => {
 
   if (!id) return mocks
 
-  const fileURL = opt.resolver(id, parent)
+  const resolver = await esmockResolver(opt)
+  const fileURL = resolver(id, parent)
   if (!fileURL && opt.isModuleNotFoundError !== false && id !== 'import')
     throw esmockErr.errModuleIdNotFound(id, parent)
 
@@ -126,7 +128,8 @@ const esmockModuleId = async (parent, treeid, defs, ids, opt, mocks, id) => {
 }
 
 const esmockModule = async (moduleId, parent, defs, gdefs, opt) => {
-  const moduleFileURL = opt.resolver(moduleId, parent)
+  const resolver = await esmockResolver(opt)
+  const moduleFileURL = resolver(moduleId, parent)
   if (!moduleFileURL)
     throw esmockErr.errModuleIdNotFound(moduleId, parent)
 
diff --git a/src/esmockReslover.js b/src/esmockResolver.js
similarity index 100%
rename from src/esmockReslover.js
rename to src/esmockResolver.js