Merge pull request #14007 from unoplatform/dev/mazi/wasm-fileext

fix: Ensure browser does not truncate file name

src/Uno.UI/ts/Windows/Storage/Pickers/FileSavePicker.ts

@@ -23,13 +23,9 @@
 				types: [],
 			};
 
-			if (suggestedFileName != "") {
-				options.suggestedName = suggestedFileName;
-			}
-
 			const acceptTypes = <Uno.Storage.Pickers.NativeFilePickerAcceptType[]>JSON.parse(fileTypesJson);
 
-			for (const acceptType of acceptTypes) {				
+			for (const acceptType of acceptTypes) {
 				const pickerAcceptType: FilePickerAcceptType = {
 					accept: {},
 					description: acceptType.description,
@@ -42,6 +38,20 @@
 				options.types.push(pickerAcceptType);
 			}
 
+			if (suggestedFileName != "") {
+				// In case the suggested file name does not end with any extension provided by the app
+				// we attach the first one if such exists. This is because JS could otherwise truncate
+				// the filename incorrectly, e.g.:
+				// "this.is.a.filename" would get truncated to "this"
+				var lowerCaseFileName = suggestedFileName.toLowerCase();
+				if (!acceptTypes.some(f => f.accept.some(a => a.extensions.some(e => lowerCaseFileName.endsWith(e.toLowerCase())))) &&
+					acceptTypes.length > 0) {
+					suggestedFileName += acceptTypes[0].accept[0].extensions[0];
+				}
+
+				options.suggestedName = suggestedFileName;
+			}
+
 			try {
 				const selectedFile = await showSaveFilePicker(options);
 				const info = Uno.Storage.NativeStorageItem.getInfos(selectedFile)[0];