3 files changed, 17 insertions, 10 deletions

diff --git a/platform/javascript/js/engine/config.js b/platform/javascript/js/engine/config.js
index 8c2636c7ab..82ff273ecf 100644
--- a/platform/javascript/js/engine/config.js
+++ b/platform/javascript/js/engine/config.js
@@ -101,6 +101,11 @@ const InternalConfig = function (initConfig) { // eslint-disable-line no-unused-
 		 */
 		gdnativeLibs: [],
 		/**
+		 * @ignore
+		 * @type {Array.<string>}
+		 */
+		fileSizes: [],
+		/**
 		 * A callback function for handling Godot's ``OS.execute`` calls.
 		 *
 		 * This is for example used in the Web Editor template to switch between project manager and editor, and for running the game.
@@ -219,6 +224,7 @@ const InternalConfig = function (initConfig) { // eslint-disable-line no-unused-
 		this.canvasResizePolicy = parse('canvasResizePolicy', this.canvasResizePolicy);
 		this.persistentPaths = parse('persistentPaths', this.persistentPaths);
 		this.gdnativeLibs = parse('gdnativeLibs', this.gdnativeLibs);
+		this.fileSizes = parse('fileSizes', this.fileSizes);
 		this.args = parse('args', this.args);
 		this.onExecute = parse('onExecute', this.onExecute);
 		this.onExit = parse('onExit', this.onExit);
diff --git a/platform/javascript/js/engine/engine.js b/platform/javascript/js/engine/engine.js
index e2d27c4c02..19a0552c8c 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(`${loadPath}.wasm`, true);
+			loadPromise = preloader.loadPromise(`${loadPath}.wasm`, size, true);
 			requestAnimationFrame(preloader.animateProgress);
 		}
 		return loadPromise;
@@ -96,7 +97,7 @@ 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`]);
 				}
 				const me = this;
 				function doInit(promise) {
@@ -137,7 +138,7 @@ 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]);
 			},
 
 			/**
diff --git a/platform/javascript/js/engine/preloader.js b/platform/javascript/js/engine/preloader.js
index 45bdcf26d4..3535fdb361 100644
--- a/platform/javascript/js/engine/preloader.js
+++ b/platform/javascript/js/engine/preloader.js
@@ -43,9 +43,9 @@ const Preloader = /** @constructor */ function () { // eslint-disable-line no-un
 		}), { headers: response.headers });
 	}
 
-	function loadFetch(file, tracker, raw) {
+	function loadFetch(file, tracker, fileSize, raw) {
 		tracker[file] = {
-			total: 0,
+			total: fileSize || 0,
 			loaded: 0,
 			done: false,
 		};
@@ -117,16 +117,16 @@ const Preloader = /** @constructor */ function () { // eslint-disable-line no-un
 		progressFunc = callback;
 	};
 
-	this.loadPromise = function (file, raw = false) {
-		return retry(loadFetch.bind(null, file, loadingFiles, raw), DOWNLOAD_ATTEMPTS_MAX);
+	this.loadPromise = function (file, fileSize, raw = false) {
+		return retry(loadFetch.bind(null, file, loadingFiles, fileSize, raw), DOWNLOAD_ATTEMPTS_MAX);
 	};
 
 	this.preloadedFiles = [];
-	this.preload = function (pathOrBuffer, destPath) {
+	this.preload = function (pathOrBuffer, destPath, fileSize) {
 		let buffer = null;
 		if (typeof pathOrBuffer === 'string') {
 			const me = this;
-			return this.loadPromise(pathOrBuffer).then(function (buf) {
+			return this.loadPromise(pathOrBuffer, fileSize).then(function (buf) {
 				me.preloadedFiles.push({
 					path: destPath || pathOrBuffer,
 					buffer: buf,