Add TypeScript types

package.json

@@ -4,6 +4,7 @@
   "description": "A transport for pino that sends messages to Google Stackdriver Logging",
   "homepage": "https://github.com/ovhemert/pino-stackdriver",
   "main": "src/index.js",
+  "types": "pino-stackdriver.d.ts",
   "scripts": {
     "dev:cli": "node ./test/debug.js | node ./src/cli.js",
     "lint": "standard",

pino-stackdriver.d.ts

@@ -0,0 +1,39 @@
+declare module "pino-stackdriver" {
+  namespace PinoStackdriver {
+    interface Options {
+      /**
+       * Full path to the JSON file containing the Google Service Credentials.
+       * Required if GOOGLE_APPLICATION_CREDENTIALS is not set as an environment variable.
+       */
+      credentials?: string;
+
+      /**
+       * The name of the project.
+       */
+      projectId: string;
+
+      /**
+       * The name of the log.
+       * @default "pino_log"
+       */
+      logName?: string;
+
+      /**
+       * The MonitoringResource to send logs to.
+       * @default { type: "global" }
+       */
+      resource?: {
+        type: string;
+        labels?: Record<string, string>;
+      }
+    }
+
+    /**
+     * Create a writestream that `pino-multi-stream` can use to send logs to.
+     * @param options
+     */
+    export const createWriteStream = (options: Options) => NodeJS.WritableStream;
+  }
+
+  export = PinoStackdriver;
+}