diff --git a/src/helpers.js b/src/helpers.js
index b5d67ca..c9178cc 100644
--- a/src/helpers.js
+++ b/src/helpers.js
@@ -1,9 +1,9 @@
 export const PROXY_SUFFIX = '?commonjs-proxy';
-export const getProxyId = id => `\0${id}${PROXY_SUFFIX}`;
+export const getProxyId = id => '\0' + id + PROXY_SUFFIX;
 export const getIdFromProxyId = proxyId => proxyId.slice(1, -PROXY_SUFFIX.length);
 
 export const EXTERNAL_SUFFIX = '?commonjs-external';
-export const getExternalProxyId = id => `\0${id}${EXTERNAL_SUFFIX}`;
+export const getExternalProxyId = id => '\0' + id + EXTERNAL_SUFFIX;
 export const getIdFromExternalProxyId = proxyId => proxyId.slice(1, -EXTERNAL_SUFFIX.length);
 
 export const HELPERS_ID = '\0commonjsHelpers.js';