fix(types): make types better

src/index.js

@@ -42,11 +42,12 @@ const noop = () => {};
  */
 
 /**
- * @typedef {ReturnType<Compiler["watch"]>} MultiWatching
+ * @typedef {ReturnType<MultiCompiler["watch"]>} MultiWatching
  */
 
+// TODO fix me after the next webpack release
 /**
- * @typedef {Compiler["outputFileSystem"] & { createReadStream?: import("fs").createReadStream, statSync?: import("fs").statSync, lstat?: import("fs").lstat, readFileSync?: import("fs").readFileSync }} OutputFileSystem
+ * @typedef {Object & { createReadStream?: import("fs").createReadStream, statSync?: import("fs").statSync, lstat?: import("fs").lstat, readFileSync?: import("fs").readFileSync }} OutputFileSystem
  */
 
 /** @typedef {ReturnType<Compiler["getInfrastructureLogger"]>} Logger */
@@ -82,15 +83,23 @@ const noop = () => {};
  * @property {Callback[]} callbacks
  * @property {Options<RequestInternal, ResponseInternal>} options
  * @property {Compiler | MultiCompiler} compiler
- * @property {Watching | MultiWatching} watching
+ * @property {Watching | MultiWatching | undefined} watching
  * @property {Logger} logger
  * @property {OutputFileSystem} outputFileSystem
  */
 
 /**
  * @template {IncomingMessage} RequestInternal
  * @template {ServerResponse} ResponseInternal
- * @typedef {Record<string, string | number> | Array<{ key: string, value: number | string }> | ((req: RequestInternal, res: ResponseInternal, context: Context<RequestInternal, ResponseInternal>) =>  void | undefined | Record<string, string | number>) | undefined} Headers
+ * @typedef {WithoutUndefined<Context<RequestInternal, ResponseInternal>, "watching">} FilledContext
+ */
+
+/** @typedef {Record<string, string | number> | Array<{ key: string, value: number | string }>} NormalizedHeaders */
+
+/**
+ * @template {IncomingMessage} RequestInternal
+ * @template {ServerResponse} ResponseInternal
+ * @typedef {NormalizedHeaders | ((req: RequestInternal, res: ResponseInternal, context: Context<RequestInternal, ResponseInternal>) =>  void | undefined | NormalizedHeaders) | undefined} Headers
  */
 
 /**
@@ -161,6 +170,18 @@ const noop = () => {};
  * @typedef {Middleware<RequestInternal, ResponseInternal> & AdditionalMethods<RequestInternal, ResponseInternal>} API
  */
 
+/**
+ * @template T
+ * @template {keyof T} K
+ * @typedef {Omit<T, K> & Partial<T>} WithOptional
+ */
+
+/**
+ * @template T
+ * @template {keyof T} K
+ * @typedef {T & { [P in K]: NonNullable<T[P]> }} WithoutUndefined
+ */
+
 /**
  * @template {IncomingMessage} RequestInternal
  * @template {ServerResponse} ResponseInternal
@@ -186,7 +207,7 @@ function wdm(compiler, options = {}) {
   }
 
   /**
-   * @type {Context<RequestInternal, ResponseInternal>}
+   * @type {WithOptional<Context<RequestInternal, ResponseInternal>, "watching" | "outputFileSystem">}
    */
   const context = {
     state: false,
@@ -195,13 +216,7 @@ function wdm(compiler, options = {}) {
     callbacks: [],
     options,
     compiler,
-    // @ts-ignore
-    // eslint-disable-next-line no-undefined
-    watching: undefined,
     logger: compiler.getInfrastructureLogger("webpack-dev-middleware"),
-    // @ts-ignore
-    // eslint-disable-next-line no-undefined
-    outputFileSystem: undefined,
   };
 
   setupHooks(context);
@@ -216,11 +231,6 @@ function wdm(compiler, options = {}) {
   if (/** @type {Compiler} */ (context.compiler).watching) {
     context.watching = /** @type {Compiler} */ (context.compiler).watching;
   } else {
-    /**
-     * @type {WatchOptions | WatchOptions[]}
-     */
-    let watchOptions;
-
     /**
      * @param {Error | null | undefined} error
      */
@@ -237,69 +247,47 @@ function wdm(compiler, options = {}) {
     if (
       Array.isArray(/** @type {MultiCompiler} */ (context.compiler).compilers)
     ) {
-      watchOptions =
-        /** @type {MultiCompiler} */
-        (context.compiler).compilers.map(
-          /**
-           * @param {Compiler} childCompiler
-           * @returns {WatchOptions}
-           */
-          (childCompiler) => childCompiler.options.watchOptions || {},
-        );
-
-      context.watching =
-        /** @type {MultiWatching} */
-        (
-          context.compiler.watch(
-            /** @type {WatchOptions}} */
-            (watchOptions),
-            errorHandler,
-          )
-        );
+      const compiler = /** @type {MultiCompiler} */ (context.compiler);
+      const watchOptions = compiler.compilers.map(
+        (childCompiler) => childCompiler.options.watchOptions || {},
+      );
+
+      context.watching = compiler.watch(watchOptions, errorHandler);
     } else {
-      watchOptions =
-        /** @type {Compiler} */ (context.compiler).options.watchOptions || {};
+      const compiler = /** @type {Compiler} */ (context.compiler);
+      const watchOptions = compiler.options.watchOptions || {};
 
-      context.watching = /** @type {Watching} */ (
-        context.compiler.watch(watchOptions, errorHandler)
-      );
+      context.watching = compiler.watch(watchOptions, errorHandler);
     }
   }
 
+  const filledContext =
+    /** @type {FilledContext<RequestInternal, ResponseInternal>} */
+    (context);
+
   const instance =
     /** @type {API<RequestInternal, ResponseInternal>} */
-    (middleware(context));
+    (middleware(filledContext));
 
   // API
-  /** @type {API<RequestInternal, ResponseInternal>} */
-  (instance).getFilenameFromUrl = (url, extra) =>
-    getFilenameFromUrl(context, url, extra);
+  instance.getFilenameFromUrl = (url, extra) =>
+    getFilenameFromUrl(filledContext, url, extra);
 
-  /** @type {API<RequestInternal, ResponseInternal>} */
-  (instance).waitUntilValid = (callback = noop) => {
-    ready(context, callback);
+  instance.waitUntilValid = (callback = noop) => {
+    ready(filledContext, callback);
   };
 
-  /** @type {API<RequestInternal, ResponseInternal>} */
-  (instance).invalidate = (callback = noop) => {
-    ready(context, callback);
+  instance.invalidate = (callback = noop) => {
+    ready(filledContext, callback);
 
-    /**
-     * @type {NonNullable<Context<RequestInternal, ResponseInternal>["watching"]>}
-     */
-    (context.watching).invalidate();
+    filledContext.watching.invalidate();
   };
 
-  /** @type {API<RequestInternal, ResponseInternal>} */
-  (instance).close = (callback = noop) => {
-    /**
-     * @type {NonNullable<Context<RequestInternal, ResponseInternal>["watching"]>}
-     */
-    (context.watching).close(callback);
+  instance.close = (callback = noop) => {
+    filledContext.watching.close(callback);
   };
 
-  /** @type {API<RequestInternal, ResponseInternal>} */
-  (instance).context = context;
+  instance.context = filledContext;
 
   return instance;
 }

src/middleware.js

@@ -16,6 +16,7 @@ const ready = require("./utils/ready");
 /** @typedef {import("./index.js").NextFunction} NextFunction */
 /** @typedef {import("./index.js").IncomingMessage} IncomingMessage */
 /** @typedef {import("./index.js").ServerResponse} ServerResponse */
+/** @typedef {import("./index.js").NormalizedHeaders} NormalizedHeaders */
 
 /**
  * @param {string} type
@@ -32,7 +33,7 @@ const BYTES_RANGE_REGEXP = /^ *bytes/i;
 /**
  * @template {IncomingMessage} Request
  * @template {ServerResponse} Response
- * @param {import("./index.js").Context<Request, Response>} context
+ * @param {import("./index.js").FilledContext<Request, Response>} context
  * @return {import("./index.js").Middleware<Request, Response>}
  */
 function wrapper(context) {
@@ -101,8 +102,7 @@ function wrapper(context) {
       let { headers } = context.options;
 
       if (typeof headers === "function") {
-        // @ts-ignore
-        headers = headers(req, res, context);
+        headers = /** @type {NormalizedHeaders} */ (headers(req, res, context));
       }
 
       /**
@@ -114,21 +114,15 @@ function wrapper(context) {
         if (!Array.isArray(headers)) {
           // eslint-disable-next-line guard-for-in
           for (const name in headers) {
-            // @ts-ignore
             allHeaders.push({ key: name, value: headers[name] });
           }
 
           headers = allHeaders;
         }
 
-        headers.forEach(
-          /**
-           * @param {{key: string, value: any}} header
-           */
-          (header) => {
-            setHeaderForResponse(res, header.key, header.value);
-          },
-        );
+        headers.forEach((header) => {
+          setHeaderForResponse(res, header.key, header.value);
+        });
       }
 
       if (!getHeaderFromResponse(res, "Content-Type")) {
@@ -152,7 +146,9 @@ function wrapper(context) {
         setHeaderForResponse(res, "Accept-Ranges", "bytes");
       }
 
-      const rangeHeader = getHeaderFromRequest(req, "range");
+      const rangeHeader =
+        /** @type {string} */
+        (getHeaderFromRequest(req, "range"));
 
       let len = /** @type {import("fs").Stats} */ (extra.stats).size;
       let offset = 0;

src/utils/compatibleAPI.js

@@ -4,6 +4,7 @@ const escapeHtml = require("./escapeHtml");
 
 /** @typedef {import("../index.js").IncomingMessage} IncomingMessage */
 /** @typedef {import("../index.js").ServerResponse} ServerResponse */
+/** @typedef {import("fs").ReadStream} ReadStream */
 
 /**
  * @typedef {Object} ExpectedRequest
@@ -37,7 +38,7 @@ function getHeaderNames(res) {
  * @template {IncomingMessage} Request
  * @param {Request} req
  * @param {string} name
- * @returns {string | undefined}
+ * @returns {string | string[] | undefined}
  */
 function getHeaderFromRequest(req, name) {
   // Express API
@@ -48,7 +49,6 @@ function getHeaderFromRequest(req, name) {
   }
 
   // Node.js API
-  // @ts-ignore
   return req.headers[name];
 }
 
@@ -256,6 +256,7 @@ async function send(req, res, filename, start, end, goNext, options) {
   const isFsSupportsStream =
     typeof options.outputFileSystem.createReadStream === "function";
 
+  /** @type {string | Buffer | ReadStream} */
   let bufferOrStream;
   let byteLength;
 

src/utils/getFilenameFromUrl.js

@@ -16,7 +16,6 @@ const cacheStore = new WeakMap();
  * @param {(value: T) => T} callback
  * @returns {any}
  */
-// @ts-ignore
 const mem = (fn, { cache = new Map() } = {}, callback) => {
   /**
    * @param {any} arguments_
@@ -79,7 +78,7 @@ function decode(input) {
 /**
  * @template {IncomingMessage} Request
  * @template {ServerResponse} Response
- * @param {import("../index.js").Context<Request, Response>} context
+ * @param {import("../index.js").FilledContext<Request, Response>} context
  * @param {string} url
  * @param {Extra=} extra
  * @returns {string | undefined}

src/utils/getPaths.js

@@ -7,7 +7,7 @@
 /**
  * @template {IncomingMessage} Request
  * @template {ServerResponse} Response
- * @param {import("../index.js").Context<Request, Response>} context
+ * @param {import("../index.js").FilledContext<Request, Response>} context
  */
 function getPaths(context) {
   const { stats, options } = context;

src/utils/ready.js

@@ -4,7 +4,7 @@
 /**
  * @template {IncomingMessage} Request
  * @template {ServerResponse} Response
- * @param {import("../index.js").Context<Request, Response>} context
+ * @param {import("../index.js").FilledContext<Request, Response>} context
  * @param {(...args: any[]) => any} callback
  * @param {Request} [req]
  * @returns {void}

src/utils/setupHooks.js

@@ -3,17 +3,17 @@
 /** @typedef {import("webpack").MultiCompiler} MultiCompiler */
 /** @typedef {import("webpack").Stats} Stats */
 /** @typedef {import("webpack").MultiStats} MultiStats */
-
 /** @typedef {import("../index.js").IncomingMessage} IncomingMessage */
 /** @typedef {import("../index.js").ServerResponse} ServerResponse */
+
 /** @typedef {Configuration["stats"]} StatsOptions */
 /** @typedef {{ children: Configuration["stats"][] }} MultiStatsOptions */
 /** @typedef {Exclude<Configuration["stats"], boolean | string | undefined>} StatsObjectOptions */
 
 /**
  * @template {IncomingMessage} Request
  * @template {ServerResponse} Response
- * @param {import("../index.js").Context<Request, Response>} context
+ * @param {import("../index.js").WithOptional<import("../index.js").Context<Request, Response>, "watching" | "outputFileSystem">} context
  */
 function setupHooks(context) {
   function invalid() {
@@ -155,9 +155,14 @@ function setupHooks(context) {
     });
   }
 
-  context.compiler.hooks.watchRun.tap("webpack-dev-middleware", invalid);
-  context.compiler.hooks.invalid.tap("webpack-dev-middleware", invalid);
-  context.compiler.hooks.done.tap("webpack-dev-middleware", done);
+  // eslint-disable-next-line prefer-destructuring
+  const compiler =
+    /** @type {import("../index.js").Context<Request, Response>} */
+    (context).compiler;
+
+  compiler.hooks.watchRun.tap("webpack-dev-middleware", invalid);
+  compiler.hooks.invalid.tap("webpack-dev-middleware", invalid);
+  compiler.hooks.done.tap("webpack-dev-middleware", done);
 }
 
 module.exports = setupHooks;

src/utils/setupOutputFileSystem.js

@@ -7,7 +7,7 @@ const memfs = require("memfs");
 /**
  * @template {IncomingMessage} Request
  * @template {ServerResponse} Response
- * @param {import("../index.js").Context<Request, Response>} context
+ * @param {import("../index.js").WithOptional<import("../index.js").Context<Request, Response>, "watching" | "outputFileSystem">} context
  */
 function setupOutputFileSystem(context) {
   let outputFileSystem;
@@ -48,6 +48,7 @@ function setupOutputFileSystem(context) {
     (context.compiler).compilers || [context.compiler];
 
   for (const compiler of compilers) {
+    // @ts-ignore
     compiler.outputFileSystem = outputFileSystem;
   }
 

src/utils/setupWriteToDisk.js

@@ -10,7 +10,7 @@ const path = require("path");
 /**
  * @template {IncomingMessage} Request
  * @template {ServerResponse} Response
- * @param {import("../index.js").Context<Request, Response>} context
+ * @param {import("../index.js").WithOptional<import("../index.js").Context<Request, Response>, "watching" | "outputFileSystem">} context
  */
 function setupWriteToDisk(context) {
   /**