From 1793329c66388baa2917571d8dc864c8ac10798d Mon Sep 17 00:00:00 2001
From: Matthew Phillips <matthew@matthewphillips.info>
Date: Thu, 4 Oct 2018 09:29:40 -0400
Subject: [PATCH] Make side-effectual imports work with globals.

Fixes #1078
---
 lib/graph/treeshake.js                            | 6 +++++-
 test/tree_shaking_test.js                         | 4 +++-
 test/treeshake/basics/main.js                     | 1 +
 test/treeshake/basics/node_modules/dep3/global.js | 5 +++++
 4 files changed, 14 insertions(+), 2 deletions(-)
 create mode 100644 test/treeshake/basics/node_modules/dep3/global.js

diff --git a/lib/graph/treeshake.js b/lib/graph/treeshake.js
index 09cec20c..c826c8f9 100644
--- a/lib/graph/treeshake.js
+++ b/lib/graph/treeshake.js
@@ -152,7 +152,11 @@ function loadFromGraph(getNode) {
 }
 
 function sideEffectualModule(node) {
-	return node && node.load.metadata.buildType === "css";
+	if(node) {
+		let md = node.load.metadata;
+		return md.buildType === "css" || md.format === "global";
+	}
+	return false;
 }
 
 function transpile(getNode, data) {
diff --git a/test/tree_shaking_test.js b/test/tree_shaking_test.js
index c369a382..8c1dc4b6 100644
--- a/test/tree_shaking_test.js
+++ b/test/tree_shaking_test.js
@@ -92,7 +92,9 @@ describe("Tree-shaking", function(){
 			describe("import 'mod'", function(){
 				it("Includes modules imported for side-effects", function(){
 					assert.equal(browser.window.DEP3_SIDE_EFFECT, true,
-						"Includes a module with needed side effects.");
+						"Includes an ES module with needed side effects.");
+					assert.equal(browser.window.DEP3_SIDE_EFFECT2, true,
+						"Includes a global module with needed side effects.");
 				});
 
 				it("Works when the dependency is CSS", function(){
diff --git a/test/treeshake/basics/main.js b/test/treeshake/basics/main.js
index b4c103b1..a4932569 100644
--- a/test/treeshake/basics/main.js
+++ b/test/treeshake/basics/main.js
@@ -12,6 +12,7 @@ import steal from "@steal";
 
 // Importing a module for its side effects
 import "dep3";
+import "dep3/global";
 
 // CSS
 import "./styles.css";
diff --git a/test/treeshake/basics/node_modules/dep3/global.js b/test/treeshake/basics/node_modules/dep3/global.js
new file mode 100644
index 00000000..ca08995f
--- /dev/null
+++ b/test/treeshake/basics/node_modules/dep3/global.js
@@ -0,0 +1,5 @@
+function one() {
+	window.DEP3_SIDE_EFFECT2 = true;
+}
+
+one();