From 6601a6f737aeea15683a90326be1f7eed5f50847 Mon Sep 17 00:00:00 2001
From: Amjad Masad <amjad.masad@gmail.com>
Date: Mon, 7 Dec 2015 11:55:21 -0800
Subject: [PATCH] Support unary expression in isPure check

---
 packages/babel-traverse/src/scope/index.js | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/packages/babel-traverse/src/scope/index.js b/packages/babel-traverse/src/scope/index.js
index 02a4122337..cd5bd880c3 100644
--- a/packages/babel-traverse/src/scope/index.js
+++ b/packages/babel-traverse/src/scope/index.js
@@ -596,6 +596,8 @@ export default class Scope {
     } else if (t.isClassProperty(node)) {
       if (node.computed && !this.isPure(node.key, constantsOnly)) return false;
       return this.isPure(node.value, constantsOnly);
+    } else if (t.isUnaryExpression(node)) {
+      return this.isPure(node.argument);
     } else {
       return t.isPureish(node);
     }