From d3ffc8ad0c12e5c31d9443f566ec185d95773dd9 Mon Sep 17 00:00:00 2001
From: Leon Krause <lk@leonkrause.com>
Date: Tue, 27 Mar 2018 11:25:03 +0200
Subject: [PATCH] Fix engine.js startGame() when loading from directory

(cherry picked from commit 3014e48ec5a985b9d143ba27b91e32b933dcfdad)
---
 platform/javascript/engine.js | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/platform/javascript/engine.js b/platform/javascript/engine.js
index dab7104af81..06ff96bc307 100644
--- a/platform/javascript/engine.js
+++ b/platform/javascript/engine.js
@@ -14,6 +14,13 @@
 
 	var loadingFiles = {};
 
+	function getPathLeaf(path) {
+
+		while (path.endsWith('/'))
+			path = path.slice(0, -1);
+		return path.slice(path.lastIndexOf('/') + 1);
+	}
+
 	function getBasePath(path) {
 
 		if (path.endsWith('/'))
@@ -25,8 +32,7 @@
 
 	function getBaseName(path) {
 
-		path = getBasePath(path);
-		return path.slice(path.lastIndexOf('/') + 1);
+		return getPathLeaf(getBasePath(path));
 	}
 
 	Engine = function Engine() {
@@ -123,7 +129,12 @@
 		this.startGame = function(mainPack) {
 
 			executableName = getBaseName(mainPack);
-			return Promise.all([this.init(getBasePath(mainPack)), this.preloadFile(mainPack)]).then(
+			return Promise.all([
+				// Load from directory,
+				this.init(getBasePath(mainPack)),
+				// ...but write to root where the engine expects it.
+				this.preloadFile(mainPack, getPathLeaf(mainPack))
+			]).then(
 				Function.prototype.apply.bind(synchronousStart, this, [])
 			);
 		};