From ca943e7343e2f84ffb5eee36d07ff963885358d7 Mon Sep 17 00:00:00 2001
From: Boopathi Rajaa <me@boopathi.in>
Date: Fri, 30 Jun 2017 17:59:05 +0200
Subject: [PATCH] Fix folding Array literals (close #608) (close #609)

---
 .../__tests__/constant-folding-test.js               | 12 ++++++++++++
 .../src/replacements.js                              |  6 ++++++
 2 files changed, 18 insertions(+)

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 60340b73a..2cacfd768 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
@@ -226,4 +226,16 @@ describe("constant-folding-plugin", () => {
     ({}).toString;
   `
   );
+
+  thePlugin(
+    "should bail for spread element in array",
+    `
+      function foo() {
+        return [...iter].length;
+      }
+      function bar() {
+        return [...iter][0];
+      }
+    `
+  );
 });
diff --git a/packages/babel-plugin-minify-constant-folding/src/replacements.js b/packages/babel-plugin-minify-constant-folding/src/replacements.js
index 0f6300d66..0cbc591b0 100644
--- a/packages/babel-plugin-minify-constant-folding/src/replacements.js
+++ b/packages/babel-plugin-minify-constant-folding/src/replacements.js
@@ -23,9 +23,15 @@ module.exports = ({ types: t }) => {
     ArrayExpression: {
       members: {
         length() {
+          if (this.elements.some(el => t.isSpreadElement(el))) {
+            return;
+          }
           return t.numericLiteral(this.elements.length);
         },
         [FALLBACK_HANDLER](i) {
+          if (this.elements.some(el => t.isSpreadElement(el))) {
+            return;
+          }
           if (typeof i === "number" || i.match(/^\d+$/)) {
             return this.elements[i] || undef;
           }