Merge pull request #2900 from NativeScript/buhov/workers-dts

Add typescript declarations for workers

tns-core-modules/declarations.d.ts

@@ -165,4 +165,4 @@ declare var exports: any;
 
 interface Array<T> {
     filter<U extends T>(pred: (a: T) => a is U): U[];
-}
+}

tns-core-modules/tns-core-modules.es2016.d.ts

@@ -1,4 +1,5 @@
 /// <reference path="./tns-core-modules.base.d.ts" />
+/// <reference path="./webworker.es2016.d.ts" />
 /// <reference path="./module.d.ts" />
 /// <reference path="./lib.dom.d.ts" />
 

tns-core-modules/webworker.es2016.d.ts

@@ -0,0 +1,88 @@
+
+/**
+ * Used to create, destroy and communicate with worker threads
+ */
+declare class Worker {
+
+    /**
+     * Creates a new worker with the given main script.
+     * @param script The first module to be loaded on the worker thread.
+     */
+    public constructor(script: string);
+
+    /**
+     * Sends message to the worker thread.
+     * @param message The message to be serialized and sent to the worker thread.
+     */
+    public postMessage(message: any) : void;
+
+    /**
+     * Terminates the execution the worker thread without calling `onclose` handler.
+     */
+    public terminate() : void;
+
+    /**
+     * Called by the runtime when a new message is received by the worker instance.
+     */
+    public onmessage : Worker.OnMessageHandler;
+
+    /**
+     * Called by the runtime when an uncaught error is propagated to the parent thread.
+     */
+    public onerror : Worker.OnErrorHandler;
+}
+
+/**
+ * Exists only in worker context. Returns the worker global object.
+ */ 
+declare var self: any;
+
+/**
+ * Exists only in worker context. It is called by the runtime when a new message is received by the worker thread.
+ */ 
+declare var onmessage : Worker.OnMessageHandler;
+
+/**
+ * Exists only in worker context. Handles uncaught errors in the worker thread. If return false the error is propagated to the parent context and passed to Worker.onerror handler.
+ */ 
+declare var onerror : Worker.OnErrorHandler;
+
+/**
+ * Exists only in worker context. Called before the worker is closed with the close() function.
+ */ 
+declare var onclose : Worker.OnCloseHandler;
+
+/**
+ * Exists only in worker context. Sends message to the parent thread.
+ */ 
+declare function postMessage(message: any) : void;
+
+/**
+ * Exists only in worker context. Closes the worker thread on the next run loop tick.
+ */ 
+declare function close() : void;
+
+declare namespace Worker {
+
+    interface MessageEvent {
+        data: any;
+    }
+
+    interface ErrorEvent {
+        message: string;
+        filename: string;
+        lineno: number;
+    }
+
+    interface OnErrorHandler {
+        (error: ErrorEvent): boolean;
+    }    
+
+    interface OnMessageHandler {
+        (message: MessageEvent): void;
+    }
+
+    interface OnCloseHandler {
+        (): void;
+    }
+}