Switch from Flow to TypeScript

.babelrc

@@ -1,5 +1,7 @@
 {
-  "presets": ["@babel/preset-flow"],
+  "presets": [
+    "@babel/preset-typescript"
+  ],
   "plugins": [
     "@babel/plugin-transform-destructuring"
   ]

.travis.yml

@@ -1,6 +1,6 @@
 language: node_js
 node_js:
-  - "8"
+  - "10"
 dist: trusty # needs Ubuntu Trusty
 # Note: if you switch to sudo: false, you'll need to launch chrome with --no-sandbox.
 # See https://github.com/travis-ci/travis-ci/issues/8836

CHANGELOG.md

@@ -1,3 +1,7 @@
+# v4.0.1, 2020-01-13
+
+Switched from Flow to TypeScript, cause momentum. Sadly TypeScript sucks at supporting shared workers, so the typings are a bit worse, but promise-worker-bi works the same.
+
 # v4.0.0, 2019-11-06
 
 Split the old PromiseWorker class into two separate classes PWBHost and PWBWorker, so they can be included separately in main and worker bundles, leading to smaller bundle sizes if you use tree shaking and dead code elimination. Savings seems to just be a couple kb of minified JS per bundle, but every byte counts!

package.json

@@ -4,15 +4,15 @@
   "description": "Promise-based messaging for Web Workers and Shared Workers",
   "main": "dist/commonjs.js",
   "module": "dist/esmodules.js",
+  "types": "dist/index.d.ts",
   "scripts": {
     "prepublish": "yarn run build",
-    "build": "rm -rf dist && rollup -c",
+    "build": "rm -rf dist && rollup -c && yarn run tsc",
     "build-test": "yarn run build && node scripts/build-test.js",
-    "flow": "flow",
-    "lint": "eslint *.js test/*.js scripts/*.js",
-    "prettier": "prettier --write '*.js' && prettier --write 'test/*.js' && prettier --write 'scripts/*.js'",
+    "lint": "eslint src/*.ts test/*.js scripts/*.js",
+    "prettier": "prettier --write 'src/*.ts' && prettier --write 'test/*.js' && prettier --write 'scripts/*.js'",
     "karma": "yarn run build-test && karma start",
-    "test": "yarn run flow && yarn run lint && yarn run karma"
+    "test": "yarn run tsc && yarn run lint && yarn run karma"
   },
   "repository": {
     "type": "git",
@@ -35,13 +35,13 @@
   "devDependencies": {
     "@babel/core": "^7.8.3",
     "@babel/plugin-transform-destructuring": "^7.8.3",
-    "@babel/preset-flow": "^7.8.3",
+    "@babel/preset-typescript": "^7.8.3",
+    "@types/sharedworker": "^0.0.29",
     "babel-eslint": "^10.0.3",
     "eslint": "^6.8.0",
     "eslint-config-airbnb-base": "^14.0.0",
     "eslint-config-prettier": "^6.9.0",
     "eslint-plugin-import": "^2.20.0",
-    "flow-bin": "^0.115.0",
     "glob": "^7.1.6",
     "husky": "^4.0.7",
     "karma": "^4.4.1",
@@ -56,7 +56,8 @@
     "rollup-plugin-babel": "^4.3.3",
     "rollup-plugin-node-builtins": "^2.1.2",
     "rollup-plugin-node-globals": "^1.4.0",
-    "rollup-plugin-node-resolve": "^5.2.0"
+    "rollup-plugin-node-resolve": "^5.2.0",
+    "typescript": "^3.7.4"
   },
   "files": [
     "dist"

rollup.config.js

@@ -1,7 +1,7 @@
 const babel = require("rollup-plugin-babel");
 
 module.exports = {
-  input: "index.js",
+  input: "src/index.ts",
   output: [
     {
       file: "dist/commonjs.js",
@@ -12,5 +12,9 @@ module.exports = {
       format: "esm"
     }
   ],
-  plugins: [babel()]
+  plugins: [
+    babel({
+      extensions: [".mjs", ".js", ".json", ".node", ".ts", ".tsx"]
+    })
+  ]
 };

index.js → src/index.ts

@@ -1,15 +1,13 @@
-// @flow
-
-type ErrorCallback = Error => void;
-type QueryCallback = (any[], number | void) => any;
+type ErrorCallback = (a: Error) => void;
+type QueryCallback = (a: any[], b: number | undefined) => any;
 
 type FakeError = {
-  name: string,
-  message: string,
-  stack?: string,
-  fileName?: string,
-  columnNumber?: number,
-  lineNumber?: number
+  name: string;
+  message: string;
+  stack?: string;
+  fileName?: string;
+  columnNumber?: number;
+  lineNumber?: number;
 };
 
 let messageIDs = 0;
@@ -28,7 +26,7 @@ const MSGTYPES = [
 ];
 
 // Inlined from https://github.com/then/is-promise
-const isPromise = obj =>
+const isPromise = (obj: any) =>
   !!obj &&
   (typeof obj === "object" || typeof obj === "function") &&
   typeof obj.then === "function";
@@ -44,13 +42,19 @@ const toFakeError = (error: Error): FakeError => {
   }
 
   // These are non-standard properties, I think only in some versions of Firefox
+  // @ts-ignore
   if (typeof error.fileName === "string") {
+    // @ts-ignore
     fakeError.fileName = error.fileName;
   }
+  // @ts-ignore
   if (typeof error.columnNumber === "number") {
+    // @ts-ignore
     fakeError.columnNumber = error.columnNumber;
   }
+  // @ts-ignore
   if (typeof error.lineNumber === "number") {
+    // @ts-ignore
     fakeError.lineNumber = error.lineNumber;
   }
 
@@ -72,17 +76,18 @@ const logError = (err: Error) => {
 };
 
 class PWBBase {
-  _callbacks: Map<number, (Error | null, any) => void>;
+  _callbacks: Map<number, (a: Error | null, b: any) => void>;
 
   _queryCallback: QueryCallback;
 
-  _workerType: "SharedWorker" | "Worker";
+  _workerType: "SharedWorker" | "Worker" | undefined;
 
   constructor() {
     // console.log('constructor', worker);
     this._callbacks = new Map();
+    this._queryCallback = () => {};
 
-    // $FlowFixMe https://github.com/facebook/flow/issues/1517
+    // @ts-ignore
     this._onMessage = this._onMessage.bind(this);
   }
 
@@ -92,15 +97,15 @@ class PWBBase {
   }
 
   // eslint-disable-next-line
-  _postMessage(obj: any[], targetHostID?: number | void) {
+  _postMessage(obj: any[], targetHostID?: number | undefined) {
     throw new Error("Not implemented");
   }
 
   _postResponse(
     messageID: number,
     error: Error | null,
-    result: any,
-    hostID: number | void
+    result?: any,
+    hostID?: number | undefined
   ) {
     // console.log('_postResponse', messageID, error, result);
     if (error) {
@@ -115,7 +120,7 @@ class PWBBase {
     }
   }
 
-  _handleQuery(messageID: number, query: any, hostID: number | void) {
+  _handleQuery(messageID: number, query: any, hostID: number | undefined) {
     // console.log('_handleQuery', messageID, query);
     try {
       const result = this._queryCallback(query, hostID);
@@ -124,10 +129,10 @@ class PWBBase {
         this._postResponse(messageID, null, result, hostID);
       } else {
         result.then(
-          finalResult => {
+          (finalResult: any) => {
             this._postResponse(messageID, null, finalResult, hostID);
           },
-          finalError => {
+          (finalError: any) => {
             this._postResponse(messageID, finalError, hostID);
           }
         );
@@ -138,7 +143,7 @@ class PWBBase {
   }
 
   // Either return messageID and type if further processing is needed, or undefined otherwise
-  _onMessageCommon(e: MessageEvent): { message: any, type: number } | void {
+  _onMessageCommon(e: MessageEvent): { message: any; type: number } | void {
     // eslint-disable-line no-undef
     // console.log('_onMessage', e.data);
     const message = e.data;
@@ -161,7 +166,7 @@ class PWBBase {
       if (typeof message[3] !== "number" && message[3] !== undefined) {
         throw new Error("Invalid hostID");
       }
-      const hostID: number | void = message[3];
+      const hostID: number | undefined = message[3];
 
       this._handleQuery(messageID, query, hostID);
       return;
@@ -192,15 +197,15 @@ class PWBBase {
 }
 
 class PWBHost extends PWBBase {
-  _errorCallback: ErrorCallback | void;
+  _errorCallback: ErrorCallback | undefined;
 
-  _hostID: number | void; // Only defined on host
+  _hostID: number | undefined; // Only defined on host
 
-  _hostIDQueue: (() => void)[] | void;
+  _hostIDQueue: (() => void)[] | undefined;
 
-  _worker: SharedWorker | Worker;
+  _worker: SharedWorker.SharedWorker | Worker;
 
-  constructor(worker: SharedWorker | Worker) {
+  constructor(worker: SharedWorker.SharedWorker | Worker) {
     super();
 
     // The following if statement used to check `worker instanceof Worker` but I have recieved
@@ -212,17 +217,18 @@ class PWBHost extends PWBBase {
     //     console.log(worker instanceof Worker);
     //
     // So instead, let's do this test for worker.port which only exists on shared workers.
+    // @ts-ignore
     if (worker.port === undefined) {
       this._workerType = "Worker";
 
-      // $FlowFixMe Seems to not recognize 'message' as valid type, but it is
+      // @ts-ignore
       worker.addEventListener("message", this._onMessage);
     } else {
       this._workerType = "SharedWorker";
 
-      // $FlowFixMe - it doesn't know if _worker is Worker or SharedWorker, but I do
+      // @ts-ignore - it doesn't know if _worker is Worker or SharedWorker, but I do
       worker.port.addEventListener("message", this._onMessage);
-      // $FlowFixMe - it doesn't know if _worker is Worker or SharedWorker, but I do
+      // @ts-ignore - it doesn't know if _worker is Worker or SharedWorker, but I do
       worker.port.start();
 
       // Handle tab close. This isn't perfect, but there is no perfect method
@@ -256,10 +262,10 @@ class PWBHost extends PWBBase {
   _postMessage(obj: any[]) {
     // console.log('_postMessage', obj);
     if (this._workerType === "Worker") {
-      // $FlowFixMe - it doesn't know if _worker is Worker or SharedWorker, but I do
+      // @ts-ignore - it doesn't know if _worker is Worker or SharedWorker, but I do
       this._worker.postMessage(obj);
     } else if (this._workerType === "SharedWorker") {
-      // $FlowFixMe - it doesn't know if _worker is Worker or SharedWorker, but I do
+      // @ts-ignore - it doesn't know if _worker is Worker or SharedWorker, but I do
       this._worker.port.postMessage(obj);
     } else {
       throw new Error("WTF");
@@ -268,7 +274,7 @@ class PWBHost extends PWBBase {
 
   postMessage(userMessage: any): Promise<any> {
     // console.log('postMessage', userMessage, targetHostID);
-    const actuallyPostMessage = (resolve, reject) => {
+    const actuallyPostMessage = (resolve: (value?: any) => void, reject: (reason?: any) => void) => {
       const messageID = messageIDs;
       messageIDs += 1;
 
@@ -304,7 +310,7 @@ class PWBHost extends PWBBase {
 
   _onMessage(e: MessageEvent) {
     const common = this._onMessageCommon(e);
-    if (common === undefined) {
+    if (!common) {
       return;
     }
 
@@ -314,7 +320,7 @@ class PWBHost extends PWBBase {
       if (message[2] !== undefined && typeof message[2] !== "number") {
         throw new Error("Invalid hostID");
       }
-      const hostID: number | void = message[2];
+      const hostID: number | undefined = message[2];
 
       this._hostID = hostID;
 
@@ -350,16 +356,21 @@ class PWBWorker extends PWBBase {
   constructor() {
     super();
 
+    // Only actually used for SharedWorker
+    this._hosts = new Map();
+    this._maxHostID = -1;
+
     if (
+      // @ts-ignore
       typeof SharedWorkerGlobalScope !== "undefined" &&
+      // @ts-ignore
       self instanceof SharedWorkerGlobalScope
     ) {
       this._workerType = "SharedWorker";
 
-      this._hosts = new Map();
-      this._maxHostID = -1;
 
       self.addEventListener("connect", e => {
+        // @ts-ignore
         const port = e.ports[0];
         port.addEventListener("message", (e2: MessageEvent) =>
           this._onMessage(e2)
@@ -405,7 +416,7 @@ class PWBWorker extends PWBBase {
     }
   }
 
-  _postMessage(obj: any[], targetHostID: number | void) {
+  _postMessage(obj: any[], targetHostID?: number | undefined) {
     // console.log('_postMessage', obj, targetHostID);
     if (this._workerType === "SharedWorker") {
       // If targetHostID has been deleted, this will do nothing, which is fine I think
@@ -415,15 +426,19 @@ class PWBWorker extends PWBBase {
         }
       });
     } else if (this._workerType === "Worker") {
+      // @ts-ignore
       self.postMessage(obj);
     } else {
       throw new Error("WTF");
     }
   }
 
-  postMessage(userMessage: any, targetHostID: number | void): Promise<any> {
+  postMessage(
+    userMessage: any,
+    targetHostID: number | undefined
+  ): Promise<any> {
     // console.log('postMessage', userMessage, targetHostID);
-    const actuallyPostMessage = (resolve, reject) => {
+    const actuallyPostMessage = (resolve: (value?: any) => void, reject: (reason?: any) => void) => {
       const messageID = messageIDs;
       messageIDs += 1;
 
@@ -446,7 +461,7 @@ class PWBWorker extends PWBBase {
 
   _onMessage(e: MessageEvent) {
     const common = this._onMessageCommon(e);
-    if (common === undefined) {
+    if (!common) {
       return;
     }
 

tsconfig.json

@@ -0,0 +1,12 @@
+{
+  "compilerOptions": {
+    "target": "esnext",
+    "moduleResolution": "node",
+    "emitDeclarationOnly": true,
+    "strict": true,
+    "esModuleInterop": true,
+    "declaration": true,
+    "declarationDir": "dist"
+  },
+  "include": ["src"]
+}