fest: add typescript definitions (#143)

fixes #19 and #75.

index.d.ts

@@ -0,0 +1,19 @@
+import { AxiosInstance, AxiosRequestConfig, AxiosPromise } from 'axios'
+import Vue from 'vue'
+
+interface NuxtAxiosInstance extends AxiosInstance {
+  $request<T = any>(config: AxiosRequestConfig): AxiosPromise<T>
+  $get<T = any>(url: string, config?: AxiosRequestConfig): AxiosPromise<T>
+  $delete<T = any>(url: string, config?: AxiosRequestConfig): AxiosPromise<T>
+  $head<T = any>(url: string, config?: AxiosRequestConfig): AxiosPromise<T>
+  $options<T = any>(url: string, config?: AxiosRequestConfig): AxiosPromise<T>
+  $post<T = any>(url: string, data?: any, config?: AxiosRequestConfig): AxiosPromise<T>
+  $put<T = any>(url: string, data?: any, config?: AxiosRequestConfig): AxiosPromise<T>
+  $patch<T = any>(url: string, data?: any, config?: AxiosRequestConfig): AxiosPromise<T>
+}
+
+declare module 'vue/types/vue' {
+  interface Vue {
+    $axios: NuxtAxiosInstance
+  }
+}

package.json

@@ -4,6 +4,7 @@
   "description": "Secure and easy axios integration with Nuxt.js",
   "license": "MIT",
   "main": "lib/module.js",
+  "types": "index.d.ts",
   "repository": "https://github.com/nuxt-community/axios-module",
   "publishConfig": {
     "access": "public"