Expose TS types & add instructions for writing declaration file

README.md

@@ -62,6 +62,24 @@ browsers that don't support AudioWorklets, as well as interoperate seamlessly wi
 Because of this, you have to use an AudioContext from `standardized-audio-context` when creating Faust nodes. If you want
 to use this loader with a vanilla AudioContext, please submit an issue or PR!
 
+### With Typescript
+
+Typescript definitions are available for the imported modules. To automatically get the correct types when you
+import a `.dsp` file, add a file ending in `.d.ts` to your project containing the following:
+
+```ts
+// faust-modules.d.ts
+
+declare module "*.dsp" {
+  import { ProcessorLoader } from "faust-loader";
+  const loader: ProcessorLoader;
+  export = loader;
+}
+```
+
+You may need to update your `tsconfig.json` to ensure declaration files in your
+project are included by the Typescript compiler.
+
 ### With Tone.js
 
 ```ts

package.json

@@ -1,7 +1,8 @@
 {
   "name": "faust-loader",
-  "version": "1.0.0",
+  "version": "1.1.0",
   "main": "dist/faustLoader.js",
+  "types": "dist/faustLoader.d.ts",
   "scripts": {
     "prepare": "install-peers",
     "build": "tsc",

src/faustLoader.ts

@@ -2,7 +2,6 @@ import { getOptions, interpolateName } from "loader-utils";
 import { LoaderDefinitionFunction } from "webpack";
 import util from "util";
 import path from "path";
-import os from "os";
 import { exec as execCallback } from "child_process";
 const exec = util.promisify(execCallback);
 import fs from "fs-extra";
@@ -13,6 +12,21 @@ interface Options {
   publicPath?: string;
 }
 
+export interface FaustAudioProcessorNode extends AudioWorkletNode {
+  getNumInputs(): number;
+  getNumOutputs(): number;
+  getParam(address: string): number;
+  getParams(): string[];
+  setParam(address: string, value: number): void;
+  getJson(): string;
+  getState(): Promise<Record<string, number>>;
+  destroy(): void;
+}
+
+export type ProcessorLoader = (
+  context: any
+) => Promise<FaustAudioProcessorNode | null | undefined>;
+
 const faustLoader: LoaderDefinitionFunction<Options> = async function (
   content
 ) {