Adds TypeScript definition for the package's supported public surface area.

Author: Micah Zoltu

index.d.ts

@@ -0,0 +1,5 @@
+declare module "solc" {
+  export type ReadCallbackResult = { contents: string } | { error: string };
+  export type ReadCallback = (path: string) => ReadCallbackResult;
+  export function compile(input: string, readCallback?: ReadCallback): string;
+}

package.json

@@ -3,6 +3,7 @@
   "version": "0.5.11",
   "description": "Solidity compiler",
   "main": "index.js",
+  "types": "index.d.ts",
   "bin": {
     "solcjs": "solcjs"
   },