1 files changed, 25 insertions, 16 deletions

diff --git a/platform/javascript/js/engine/engine.js b/platform/javascript/js/engine/engine.js
index c51955ed3d..17a8df9e29 100644
--- a/platform/javascript/js/engine/engine.js
+++ b/platform/javascript/js/engine/engine.js
@@ -35,14 +35,15 @@ const Engine = (function () {
 	 * Load the engine from the specified base path.
 	 *
 	 * @param {string} basePath Base path of the engine to load.
+	 * @param {number=} [size=0] The file size if known.
 	 * @returns {Promise} A Promise that resolves once the engine is loaded.
 	 *
 	 * @function Engine.load
 	 */
-	Engine.load = function (basePath) {
+	Engine.load = function (basePath, size) {
 		if (loadPromise == null) {
 			loadPath = basePath;
-			loadPromise = preloader.loadPromise(`${loadPath}.wasm`);
+			loadPromise = preloader.loadPromise(`${loadPath}.wasm`, size, true);
 			requestAnimationFrame(preloader.animateProgress);
 		}
 		return loadPromise;
@@ -96,23 +97,31 @@ const Engine = (function () {
 						initPromise = Promise.reject(new Error('A base path must be provided when calling `init` and the engine is not loaded.'));
 						return initPromise;
 					}
-					Engine.load(basePath);
+					Engine.load(basePath, this.config.fileSizes[`${basePath}.wasm`]);
 				}
-				preloader.setProgressFunc(this.config.onProgress);
-				let config = this.config.getModuleConfig(loadPath, loadPromise);
 				const me = this;
-				initPromise = new Promise(function (resolve, reject) {
-					Godot(config).then(function (module) {
-						module['initFS'](me.config.persistentPaths).then(function (fs_err) {
-							me.rtenv = module;
-							if (me.config.unloadAfterInit) {
-								Engine.unload();
-							}
-							resolve();
-							config = null;
+				function doInit(promise) {
+					// Care! Promise chaining is bogus with old emscripten versions.
+					// This caused a regression with the Mono build (which uses an older emscripten version).
+					// Make sure to test that when refactoring.
+					return new Promise(function (resolve, reject) {
+						promise.then(function (response) {
+							const cloned = new Response(response.clone().body, { 'headers': [['content-type', 'application/wasm']] });
+							Godot(me.config.getModuleConfig(loadPath, cloned)).then(function (module) {
+								const paths = me.config.persistentPaths;
+								module['initFS'](paths).then(function (err) {
+									me.rtenv = module;
+									if (me.config.unloadAfterInit) {
+										Engine.unload();
+									}
+									resolve();
+								});
+							});
 						});
 					});
-				});
+				}
+				preloader.setProgressFunc(this.config.onProgress);
+				initPromise = doInit(loadPromise);
 				return initPromise;
 			},
 
@@ -133,7 +142,7 @@ const Engine = (function () {
 			 * @returns {Promise} A Promise that resolves once the file is loaded.
 			 */
 			preloadFile: function (file, path) {
-				return preloader.preload(file, path);
+				return preloader.preload(file, path, this.config.fileSizes[file]);
 			},
 
 			/**