sdk: replace all the early-load logic with promises

static/sdk.js

@@ -12,27 +12,14 @@
 		return currentScript.replace(currentScriptFile, '');
 	};
 	
-	var loadScript = function(url, onLoad) {
+	var loadScript = function(url) {
+		return new Promise(function(resolve, reject) {
 			var script = document.createElement('script');
-		script.onload = onLoad;
+			script.onload = resolve;
+			script.onerror = reject;
 			script.src = url;
 			document.head.appendChild(script);
-	};
+		});
-	
-	var loadScripts = function(urls, onLoad) {
-		// load sequentially
-		var i = 0;
-		var loadNext = function() {
-			if (i === urls.length) {
-				onLoad();
-				return;
-			}
-			
-			var url = urls[i];
-			i += 1;
-			loadScript(url, loadNext);
-		};
-		loadNext();
 	};
 	
     var formatBytes = function(bytes) {
@@ -221,7 +208,7 @@
 </div>
 `;
 
-	var initArea = function (elementSelector, onUploaded, onClose) {
+	var initArea = function (aboutInfo, elementSelector, onUploaded, onClose) {
 		onUploaded = onUploaded || function () { };
 		onClose = onClose || function () { };
 
@@ -233,15 +220,12 @@
 		// <input type="hidden" name="MAX_FILE_SIZE" value="` + ret.MaxUploadBytes + `" /> 
 
 		// Create a new div for ourselves on top of the existing area
-		$.get(contented.baseURL + "about", function (ret) {
 		
 		var extraText = "";
-			if (ret.MaxUploadBytes > 0) {
+		if (aboutInfo.MaxUploadBytes > 0) {
-				extraText = " (max " + formatBytes(ret.MaxUploadBytes) + ")";
+			extraText = " (max " + formatBytes(aboutInfo.MaxUploadBytes) + ")";
 		}
 
-		
-
 		var $f = $("<div>").html(widgetHtml);
 		$f.find(".contented-extratext").text(extraText);
 
@@ -512,24 +496,6 @@
 
 		}
 
-				// .
-
-			});
-
-		});
-
-	};
-
-	var afterScriptsLoaded = function() {		
-			
-		// Update fields in global variable
-		contented.init = initArea;
-		contented.loaded = true;
-		
-		// Call initArea for all pre-initialised elements
-		for (var i = 0; i < contented.__preInit.length; ++i) {
-			initArea(contented.__preInit[i][0], contented.__preInit[i][1], contented.__preInit[i][2]);
-		}
 	};
 
 	var init = function() {
@@ -537,6 +503,34 @@
 		var currentScriptPath = getCurrentScriptPath();
 		var baseURL = currentScriptPath.replace('sdk.js', '');
 		
+		// Kick off background promises
+
+		var loader = new Promise(function(resolve, reject) {
+			if (typeof jQuery === "undefined") {
+				loadScript(contented.baseURL + "jquery-3.7.0.min.js").then(resolve);
+			} else {
+				resolve();
+			}
+
+		}).then(function() { return new Promise(function(resolve, reject) {
+			if (typeof DrawingBoard === "undefined") {
+				loadScript(contented.baseURL + "drawingboard-0.4.6.min.js").then(resolve);
+			} else {
+				resolve();
+			}
+
+		})}).then(function() { return new Promise(function(resolve, reject) {
+			$.get(contented.baseURL + "about", function (aboutInfo) {
+				resolve(aboutInfo);
+			});
+
+		})}).then(function(aboutInfo) {
+			// Update fields in global variable
+			window.contented.loaded = true;
+			
+			return aboutInfo;
+		});
+
 		window.contented = {
 			"loaded": false,
 			
@@ -552,7 +546,9 @@
 			* @param Function   onClose       Called when the widget is being destroyed
 			*/
 			"init": function(elementSelector, onUploaded, onClose) {
-				contented.__preInit.push([elementSelector, onUploaded, onClose]);
+				loader.then(function(aboutInfo) {
+					initArea(aboutInfo, elementSelector, onUploaded, onClose);
+				});
 			},
 			
 			/**
@@ -589,16 +585,6 @@
 			}
 		};
 	
-		// Load scripts
-		var needScripts = [];
-		if (typeof jQuery === "undefined") {
-			needScripts.push(contented.baseURL + "jquery-3.7.0.min.js");
-		}
-		if (typeof DrawingBoard === "undefined") {
-			needScripts.push(contented.baseURL + "drawingboard-0.4.6.min.js");
-		}
-		
-		loadScripts(needScripts, afterScriptsLoaded);
 	};
 
 	init();