Handle joining of absolute zip paths

2 files changed, 14 insertions, 3 deletions

diff --git a/lib/zipfile.js b/lib/zipfile.js
index 708b07a..91c5f04 100644
--- a/lib/zipfile.js
+++ b/lib/zipfile.js
@@ -38,7 +38,11 @@ function openArrayBuffer(arrayBuffer) {
 }
 
 function joinZipPath(first, second) {
-    // In general, we should check first and second for trailing and leading slashes,
-    // but in our specific case this seems to be sufficient
-    return first + "/" + second;
+    if (second.charAt(0) === "/") {
+        return second;
+    } else {
+        // In general, we should check first and second for trailing and leading slashes,
+        // but in our specific case this seems to be sufficient
+        return first + "/" + second;
+    }
 }
diff --git a/test/zipfile.tests.js b/test/zipfile.tests.js
index d539307..52389a8 100644
--- a/test/zipfile.tests.js
+++ b/test/zipfile.tests.js
@@ -29,5 +29,12 @@ test("joinZipPath", {
             zipfile.joinZipPath("one/two", "three/four"),
             "one/two/three/four"
         )
+    },
+
+    "joining base to absolute path ignores base": function() {
+        assert.equal(
+            zipfile.joinZipPath("one/two", "/three/four"),
+            "/three/four"
+        )
     }
 });