diff --git a/lib/internal/modules/esm/loader.js b/lib/internal/modules/esm/loader.js
index 60f1e31f94e86e..820b593446ca79 100644
--- a/lib/internal/modules/esm/loader.js
+++ b/lib/internal/modules/esm/loader.js
@@ -1,7 +1,6 @@
 'use strict';
 
 const {
-  ERR_INVALID_ARG_TYPE,
   ERR_INVALID_RETURN_PROPERTY,
   ERR_INVALID_RETURN_PROPERTY_VALUE,
   ERR_INVALID_RETURN_VALUE,
@@ -9,6 +8,7 @@ const {
   ERR_UNKNOWN_MODULE_FORMAT
 } = require('internal/errors').codes;
 const { URL } = require('url');
+const { validateString } = require('internal/validators');
 const ModuleMap = require('internal/modules/esm/module_map');
 const ModuleJob = require('internal/modules/esm/module_job');
 const defaultResolve = require('internal/modules/esm/default_resolve');
@@ -52,8 +52,8 @@ class Loader {
 
   async resolve(specifier, parentURL) {
     const isMain = parentURL === undefined;
-    if (!isMain && typeof parentURL !== 'string')
-      throw new ERR_INVALID_ARG_TYPE('parentURL', 'string', parentURL);
+    if (!isMain)
+      validateString(parentURL, 'parentURL');
 
     const resolved = await this._resolve(specifier, parentURL, defaultResolve);
 
diff --git a/lib/internal/modules/esm/module_map.js b/lib/internal/modules/esm/module_map.js
index f4786f8e9ef0be..a9d0c23c0e5ee9 100644
--- a/lib/internal/modules/esm/module_map.js
+++ b/lib/internal/modules/esm/module_map.js
@@ -4,19 +4,16 @@ const ModuleJob = require('internal/modules/esm/module_job');
 const { SafeMap } = require('internal/safe_globals');
 const debug = require('util').debuglog('esm');
 const { ERR_INVALID_ARG_TYPE } = require('internal/errors').codes;
+const { validateString } = require('internal/validators');
 
 // Tracks the state of the loader-level module cache
 class ModuleMap extends SafeMap {
   get(url) {
-    if (typeof url !== 'string') {
-      throw new ERR_INVALID_ARG_TYPE('url', 'string', url);
-    }
+    validateString(url, 'url');
     return super.get(url);
   }
   set(url, job) {
-    if (typeof url !== 'string') {
-      throw new ERR_INVALID_ARG_TYPE('url', 'string', url);
-    }
+    validateString(url, 'url');
     if (job instanceof ModuleJob !== true) {
       throw new ERR_INVALID_ARG_TYPE('job', 'ModuleJob', job);
     }
@@ -24,9 +21,7 @@ class ModuleMap extends SafeMap {
     return super.set(url, job);
   }
   has(url) {
-    if (typeof url !== 'string') {
-      throw new ERR_INVALID_ARG_TYPE('url', 'string', url);
-    }
+    validateString(url, 'url');
     return super.has(url);
   }
 }