added TypeScript typings

resolves #25

Author: saraedum

Diff for: package.json

@@ -3,6 +3,7 @@
   "version": "3.5.0",
   "description": "Async computed properties for Vue",
   "main": "dist/vue-async-computed.js",
+  "types": "types/index.d.ts",
   "files": [
     "bin/",
     "dist/"

Diff for: types/index.d.ts

@@ -0,0 +1,48 @@
+import Vue, { PluginFunction } from "vue";
+
+export interface IAsyncComputedOptions {
+	errorHandler?: (error: string | Error) => void;
+	useRawError?: boolean;
+}
+
+export default class AsyncComputed {
+	constructor(options?: IAsyncComputedOptions)
+	static install: PluginFunction<never>;
+	static version: string;
+}
+
+type AsyncComputedGetter<T> = () => Promise<T>;
+interface IAsyncComputedProperty<T> {
+	default?: T | (() => T);
+	get: AsyncComputedGetter<T>;
+	watch?: () => void;
+	shouldUpdate?: () => boolean;
+	lazy?: boolean;
+}
+
+interface IAsyncComputedProperties {
+	[K: string]: AsyncComputedGetter<any> | IAsyncComputedProperty<any>;
+}
+
+declare module "vue/types/options" {
+	// tslint:disable-next-line:interface-name
+	interface ComponentOptions<V extends Vue> {
+		asyncComputed?: IAsyncComputedProperties;
+	}
+}
+
+interface IASyncComputedState {
+	state: "updating" | "success" | "error";
+	updating: boolean;
+	success: boolean;
+	error: boolean;
+	exception: Error | null;
+	update: () => void;
+}
+
+declare module "vue/types/vue" {
+	// tslint:disable-next-line:interface-name
+	interface Vue {
+		$asyncComputed: {[K: string]: IASyncComputedState };
+	}
+}