Added path methods to the FileSystem methods. Added unit tests.

FileSystem/file_system.d.ts

@@ -127,4 +127,24 @@ export declare module knownFolders {
     * Gets the Temporary (Caches) folder available for the current application. This Folder is private for the application and not accessible from Users/External apps.
     */
     export function temp(): Folder;
+}
+
+/**
+* Enables path-specific operations like join, extension, etc.
+*/
+export declare module path {
+    /**
+    * Normalizes a path, taking care of occurrances like ".." and "//"
+    */
+    export function normalize(path: string): string;
+
+    /**
+    * Joins all the provided string components, forming a valid and normalized path.
+    */
+    export function join(...paths: string[]): string;
+
+    /**
+    * Gets the string used to separate file paths.
+    */
+    export var separator: string;
 }

FileSystem/file_system.ts

@@ -112,7 +112,7 @@ export class FileSystemEntity {
 
         var fileAccess = getFileAccess();
         var path = parentFolder.path;
-        var newPath = fileAccess.concatPath(path, newName);
+        var newPath = fileAccess.joinPath(path, newName);
 
         var that = this;
         var localSucceess = function () {
@@ -294,7 +294,7 @@ export class Folder extends FileSystemEntity {
     */
     public contains(name: string): boolean {
         var fileAccess = getFileAccess();
-        var path = fileAccess.concatPath(this.path, name);
+        var path = fileAccess.joinPath(this.path, name);
 
         if (fileAccess.fileExists(path)) {
             return true;
@@ -333,7 +333,7 @@ export class Folder extends FileSystemEntity {
     */
     public getFile(name: string): File {
         var fileAccess = getFileAccess();
-        var path = fileAccess.concatPath(this.path, name);
+        var path = fileAccess.joinPath(this.path, name);
 
         var onError = function (error) {
             throw error;
@@ -352,7 +352,7 @@ export class Folder extends FileSystemEntity {
     */
     public getFolder(name: string): Folder {
         var fileAccess = getFileAccess();
-        var path = fileAccess.concatPath(this.path, name);
+        var path = fileAccess.joinPath(this.path, name);
 
         var onError = function (error) {
             throw error;
@@ -461,4 +461,29 @@ export module knownFolders {
 
         return _temp;
     }
+}
+
+/**
+* Enables path-specific operations like join, extension, etc.
+*/
+export module path {
+    /**
+    * Normalizes a path, taking care of occurrances like ".." and "//"
+    */
+    export function normalize(path: string): string {
+        return getFileAccess().normalizePath(path);
+    }
+
+    /**
+    * Joins all the provided string components, forming a valid and normalized path.
+    */
+    export function join(...paths: string[]): string {
+        var fileAccess = getFileAccess();
+        return fileAccess.joinPaths(paths);
+    }
+
+    /**
+    * Gets the string used to separate file paths.
+    */
+    export var separator = getFileAccess().getPathSeparator();
 }

FileSystem/file_system_access.android.ts

@@ -2,7 +2,7 @@
 import textModule = require("text/text");
 
 export class FileSystemAccess {
-    private _pathSeparator = java.io.File.separator;
+    private _pathSeparator = java.io.File.separator.toString();
 
     public getLastModified(path: string): Date {
         var javaFile = new java.io.File(path);
@@ -90,10 +90,6 @@ export class FileSystemAccess {
         return exists && dir;
     }
 
-    public concatPath(left: string, right: string): string {
-        return left + this._pathSeparator + right;
-    }
-
     public deleteFile(path: string, onSuccess?: () => any, onError?: (error: any) => any) {
         try {
             var javaFile = new java.io.File(path);
@@ -398,4 +394,38 @@ export class FileSystemAccess {
             }
         }
     }
+
+    public getPathSeparator(): string {
+        return this._pathSeparator;
+    }
+
+    public normalizePath(path: string): string {
+        var file = new java.io.File(path);
+        return file.getAbsolutePath();
+    }
+
+    public joinPath(left: string, right: string): string {
+        var file1 = new java.io.File(left);
+        var file2 = new java.io.File(file1, right);
+
+        return file2.getAbsolutePath();
+    }
+
+    public joinPaths(paths: string[]): string {
+        if (!paths || paths.length === 0) {
+            return "";
+        }
+
+        if (paths.length === 1) {
+            return paths[0];
+        }
+
+        var i,
+            result = paths[0];
+        for (i = 1; i < paths.length; i++) {
+            result = this.joinPath(result, paths[i]);
+        }
+
+        return this.normalizePath(result);
+    }
 }

FileSystem/file_system_access.d.ts

@@ -13,7 +13,7 @@ export declare class FileSystemAccess {
 
     fileExists(path: string): boolean;
     folderExists(path: string): boolean;
-    concatPath(left: string, right: string): string;
+    
     deleteFile(path: string, onSuccess?: () => any, onError?: (error: any) => any);
     deleteFolder(path: string, isKnown: boolean, onSuccess?: () => any, onError?: (error: any) => any);
     emptyFolder(path: string, onSuccess?: () => any, onError?: (error: any) => any): void;
@@ -25,5 +25,11 @@ export declare class FileSystemAccess {
     writeText(path: string, content: string, onSuccess?: () => any, onError?: (error: any) => any, encoding?: string);
 
     getFileExtension(path: string): string;
+
+    // path methods
+    getPathSeparator(): string;
+    normalizePath(path: string): string;
+    joinPath(left: string, right: string): string;
+    joinPaths(paths: string[]): string;
 }
  

FileSystem/file_system_access.ios.ts

@@ -346,4 +346,37 @@ export class FileSystemAccess {
             }
         }
     }
+
+    public getPathSeparator(): string {
+        return "/";
+    }
+
+    public normalizePath(path: string): string {
+        var nsString: Foundation.NSString = Foundation.NSString.stringWithString(path);
+        var normalized = nsString.stringByStandardizingPath();
+
+        return normalized;
+    }
+
+    public joinPath(left: string, right: string): string {
+        var nsString: Foundation.NSString = Foundation.NSString.stringWithString(left);
+        return nsString.stringByAppendingPathComponent(right);
+    }
+
+    public joinPaths(paths: string[]): string {
+        if (!paths || paths.length === 0) {
+            return "";
+        }
+
+        var nsArray = new Foundation.NSMutableArray(paths.length);
+
+        var i;
+        for (i = 0; i < paths.length; i++) {
+            nsArray.addObject(paths[i]);
+        }
+
+        // TODO: Static methods return NSString instance to enable its methods
+        var nsString: any = Foundation.NSString.pathWithComponents(nsArray);
+        return nsString.stringByStandardizingPath();
+    }
 }