Add TypeScript typings

index.d.ts

@@ -0,0 +1,58 @@
+import type { Plugin } from "postcss";
+
+declare type GenerateScopedNameFunction = (
+  name: string,
+  filename: string,
+  css: string
+) => string;
+
+declare type LocalsConventionFunction = (
+  originalClassName: string,
+  generatedClassName: string,
+  inputFile: string
+) => string;
+
+declare class Loader {
+  constructor(root: string, plugins: Plugin[]);
+
+  fetch(
+    file: string,
+    relativeTo: string,
+    depTrace: string
+  ): Promise<{ [key: string]: string }>;
+
+  finalSource?: string | undefined;
+}
+
+declare interface Options {
+  getJSON?(
+    cssFilename: string,
+    json: { [name: string]: string },
+    outputFilename?: string
+  ): void;
+
+  localsConvention?:
+    | "camelCase"
+    | "camelCaseOnly"
+    | "dashes"
+    | "dashesOnly"
+    | LocalsConventionFunction;
+
+  scopeBehaviour?: "global" | "local";
+  globalModulePaths?: RegExp[];
+
+  generateScopedName?: string | GenerateScopedNameFunction;
+
+  hashPrefix?: string;
+  exportGlobals?: boolean;
+  root?: string;
+
+  Loader?: typeof Loader;
+}
+
+declare interface PostcssModulesPlugin {
+  (options: Options): Plugin;
+  postcss: true;
+}
+
+export = PostcssModulesPlugin;

package.json

@@ -3,6 +3,7 @@
   "version": "4.0.0",
   "description": "PostCSS plugin to use CSS Modules everywhere",
   "main": "build/index.js",
+  "types": "index.d.ts",
   "keywords": [
     "postcss",
     "css",