diff --git a/lib/installer.js b/lib/installer.js
index 928e6b2..3948bea 100644
--- a/lib/installer.js
+++ b/lib/installer.js
@@ -66,7 +66,7 @@ function getMaven(version, mirror) {
 }
 exports.getMaven = getMaven;
 function get_server_url(mirror) {
-    if (mirror && mirror.indexOf("http") == 0) {
+    if (mirror && (mirror.indexOf("http") === 0)) {
         return mirror;
     }
     switch (mirror) {
diff --git a/src/installer.ts b/src/installer.ts
index 955c444..e7a836e 100644
--- a/src/installer.ts
+++ b/src/installer.ts
@@ -32,7 +32,7 @@ export async function getMaven(version: string, mirror: string) {
 }
 
 function get_server_url(mirror: string) {
-  if (mirror && mirror.indexOf("http") == 0) {
+  if (mirror && (mirror.indexOf("http") === 0)) {
     return mirror;
   }
   switch (mirror) {