diff --git a/package.json b/package.json
index e7241707..a5bd6dd0 100644
--- a/package.json
+++ b/package.json
@@ -26,7 +26,7 @@
   },
   "dependencies": {
     "expression-expander": "^7.0.0",
-    "pratt-parser": "^7.0.9"
+    "pratt-parser": "^8.0.0"
   },
   "devDependencies": {
     "ava": "^1.0.1",
diff --git a/rollup.config.js b/rollup.config.js
index 036bf1ec..399da302 100644
--- a/rollup.config.js
+++ b/rollup.config.js
@@ -12,14 +12,6 @@ export default {
     interop: false
   },
   plugins: [resolve(), commonjs(), cleanup()],
-  external: [
-    "os",
-    "util",
-    "child_process",
-    "path",
-    "fs",
-    "crypto",
-    "pratt-parser"
-  ],
+  external: ["os", "util", "child_process", "path", "fs", "crypto"],
   input: pkg.module
 };