From bda4c1d1846a484f3f4af714cbef0ac9ef2a174c Mon Sep 17 00:00:00 2001
From: Boopathi Rajaa <me@boopathi.in>
Date: Thu, 3 Nov 2016 00:30:17 +0100
Subject: [PATCH] Fix path.evaluate for runtime errors in constant-folding
 (close #245)

---
 .../__tests__/constant-folding-test.js              | 11 +++++++++++
 .../src/index.js                                    | 13 ++++++++++++-
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/packages/babel-plugin-minify-constant-folding/__tests__/constant-folding-test.js b/packages/babel-plugin-minify-constant-folding/__tests__/constant-folding-test.js
index 9d54194b1..30fe72afc 100644
--- a/packages/babel-plugin-minify-constant-folding/__tests__/constant-folding-test.js
+++ b/packages/babel-plugin-minify-constant-folding/__tests__/constant-folding-test.js
@@ -49,4 +49,15 @@ describe("constant-folding-plugin", () => {
     `);
     expect(transform(source)).toBe(expected);
   });
+
+  it("should handle runtime errors", () => {
+    const source = unpad(`
+      try {
+        x({
+          toString: 0
+        } + '');
+      } catch (e) {}
+    `);
+    expect(transform(source)).toBe(source);
+  });
 });
diff --git a/packages/babel-plugin-minify-constant-folding/src/index.js b/packages/babel-plugin-minify-constant-folding/src/index.js
index da4865a08..4462037bc 100644
--- a/packages/babel-plugin-minify-constant-folding/src/index.js
+++ b/packages/babel-plugin-minify-constant-folding/src/index.js
@@ -92,7 +92,7 @@ module.exports = ({ types: t, traverse }) => {
           return;
         }
 
-        const res = path.evaluate();
+        const res = evaluate(path);
         if (res.confident) {
           // Avoid fractions because they can be longer than the original expression.
           // There is also issues with number percision?
@@ -118,3 +118,14 @@ module.exports = ({ types: t, traverse }) => {
     },
   };
 };
+
+function evaluate(path) {
+  try {
+    return path.evaluate();
+  } catch (e) {
+    return {
+      confident: false,
+      error: e
+    };
+  }
+}