Adding typescript definitions to package

index.d.ts

@@ -0,0 +1,37 @@
+import copyWebpackPlugin = require("copy-webpack-plugin");
+
+type CwpParams = ConstructorParameters<typeof copyWebpackPlugin>;
+type CopyPattern = Exclude<CwpParams[0][0],string>
+type CopyWebpackPluginConfiguration = CwpParams[1];
+
+declare interface CopySpec {
+    path: string,
+    dist?: string,
+    cwpPatternConfig?: CopyPattern,
+}
+
+declare interface EntrySpec extends CopySpec {
+    type?: 'js' | 'css',
+    attributes?: Record<string,string>
+};
+
+declare interface ExternalsDefinition {
+    module: string,
+    dist?: string,
+    entry: string | EntrySpec | Array<string | EntrySpec>,
+    global?: string | null,
+    supplements: Array<string | CopySpec>,
+    append?: boolean,
+}
+
+export = class HtmlWebpackExternalsPlugin {
+    constructor(options: {
+        externals: ExternalsDefinition[],
+        hash?: boolean,
+        outputPath?: string,
+        publicPath?: string | null,
+        files?: string | string[] | null,
+        cwpOptions?: CopyWebpackPluginConfiguration,
+        enabled?: boolean,
+    });
+}

package.json

@@ -9,6 +9,7 @@
     "externals"
   ],
   "main": "lib/index.js",
+  "types": "index.d.ts",
   "scripts": {
     "build": "rm -rf lib && babel src --out-dir lib --source-maps --copy-files",
     "postpublish": "create-github-release $TAG",
@@ -63,6 +64,7 @@
     "html-webpack-plugin": "^2.0.0"
   },
   "dependencies": {
+    "@types/copy-webpack-plugin": "^4.4.4",
     "ajv": "^6.1.1",
     "copy-webpack-plugin": "^4.4.1",
     "html-webpack-include-assets-plugin": "^1.0.2"