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Add Worker playground (#322)
* Add Worker playground * fix: Changes following reviewer feedback * feat: Changes following reviewer feedback * Update README.md Co-authored-by: Dipika Bhattacharya <dipika@foss-community.org> --------- Co-authored-by: Brian Smith <brian@smith.berlin> Co-authored-by: Dipika Bhattacharya <dipika@foss-community.org>
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‎README.md

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@@ -93,7 +93,7 @@ Code examples that accompany various MDN DOM and Web API documentation pages.
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- The "web-share" directory contains a basic demo to show usage of the [Web Share API](https://developer.mozilla.org/docs/Web/API/Navigator/share). [View the demo live](https://mdn.github.io/dom-examples/web-share/).
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- The "web-workers" directory contains a basic web worker to demonstrate how [Web Workers](https://developer.mozilla.org/docs/Web/API/Web_Workers_API) work. [View the demo live](https://mdn.github.io/dom-examples/web-workers/simple-web-worker/).
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- The "web-workers" directory contains several demos that show how [Web Workers](https://developer.mozilla.org/docs/Web/API/Web_Workers_API) operate. For example, view the live [simple web worker demo](https://mdn.github.io/dom-examples/web-workers/simple-web-worker/).
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- The ["webgl-examples"](webgl-examples/README.md) directory contains a number of WebGL examples that demonstrate the [WebGL API](https://developer.mozilla.org/docs/Web/API/WebGL_API), which is used for 2D and 3D graphics on the web.
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‎web-workers/worker-playground/bad-syntax-worker.js

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++++++

‎web-workers/worker-playground/dedicated.js

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addEventListener("message", function (evt) {
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let { generation, str } = evt.data;
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let result;
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try {
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result = eval(str) + "";
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} catch (ex) {
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result = "Exception: " + ex;
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}
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postMessage({
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generation,
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result,
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});
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});

‎web-workers/worker-playground/dynamic-error-shared-worker.js

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function msghandler(evt) {
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if (evt.data === "throw") {
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throw new Error("Throw requested by postMessage()");
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}
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}
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onconnect = function (evt) {
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evt.ports[0].onmessage = msghandler;
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throw new Error("Throw initiated by connect!");
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};

‎web-workers/worker-playground/dynamic-importer.js

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onmessage = function (evt) {
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if (evt.data.script) {
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try {
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importScripts(evt.data.script);
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if (self.workerMethod) {
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workerMethod();
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}
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} catch (ex) {
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let recovered = false;
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// Scripts with partial in them should be handled for side-effect.
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if (/partial/i.test(evt.data.script)) {
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recovered = true;
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try {
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workerMethod();
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} catch (ex2) {
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ex = ex2;
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}
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}
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postMessage({
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iMsg: evt.data.iMsg,
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script: evt.data.script,
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errored: true,
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recovered,
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message: ex.message,
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filename: ex.filename || ex.fileName,
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stringified: ex + "",
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stack: ex.stack + "",
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});
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return;
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}
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postMessage({
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errored: false,
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filname: null,
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stack: null,
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});
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}
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};

‎web-workers/worker-playground/id-typo-worker.js

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var foo = 1;
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fo++;

‎web-workers/worker-playground/import-checks.html

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<!doctype html>
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<html>
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<head>
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<meta charset="UTF-8" />
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</head>
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<body>
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<script type="application/javascript">
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const crossOrigin = "https://worker-playground-crossorigin.glitch.me";
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const syntaxScriptName = "bad-syntax-worker.js";
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const idTypoWorkerScriptName = "id-typo-worker.js";
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const topLevelThrowScriptName = "top-level-throw.js";
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const topLevelPartialScriptName = "top-level-partial.js";
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const methodThrowScriptName = "method-throws-worker.js";
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function makeRedirectedUrl(scriptName) {
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return `${crossOrigin}/redirects/script.js?script=${scriptName}&cookieCheck=true`;
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}
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const w = new Worker("dynamic-importer.js");
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let iMsg = 0;
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function sendAndAwait(data) {
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data.iMsg = ++iMsg;
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return new Promise((resolve) => {
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w.addEventListener(
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"message",
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(evt) => {
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resolve(evt.data);
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},
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{ once: true },
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);
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w.postMessage(data);
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});
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}
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async function workerDriver() {
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let msg;
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msg = await sendAndAwait({
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script: makeRedirectedUrl(syntaxScriptName),
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});
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console.log("Syntax error:", msg);
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msg = await sendAndAwait({
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script: makeRedirectedUrl(idTypoWorkerScriptName),
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});
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console.log("Id typo error:", msg);
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msg = await sendAndAwait({
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script: makeRedirectedUrl(topLevelThrowScriptName),
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});
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console.log("Top level throw error:", msg);
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msg = await sendAndAwait({
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script: makeRedirectedUrl(topLevelPartialScriptName),
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});
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console.log("Top level method throw after top-level throw error:", msg);
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msg = await sendAndAwait({
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script: makeRedirectedUrl(methodThrowScriptName),
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});
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console.log("Method throw error:", msg);
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w.terminate();
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}
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workerDriver();
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</script>
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</body>
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</html>

‎web-workers/worker-playground/index.html

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<!DOCTYPE html>
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<html lang="en">
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<head>
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<title>Worker Playground</title>
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<meta charset="utf-8" />
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<meta name="viewport" content="width=device-width, initial-scale=1" />
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<link rel="stylesheet" href="style.css" />
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<script src="script.js" defer></script>
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</head>
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<body>
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<h1>Worker Playground!</h1>
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<p>
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Type your code into the following text area, and the app will
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<code>eval()</code> it in a Dedicated Worker, Shared Worker, and Service
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Worker, letting you know whether it is supported and what it returns in
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those contexts. For example, try <code>XMLHttpRequest</code>,
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<code>registration</code>, or <code>location</code>:
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</p>
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<textarea id="inp" cols="80" rows="10"></textarea>
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<h3>Dedicated Worker output:</h3>
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<textarea id="dedicated" cols="80" rows="10"></textarea>
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<h3>Shared Worker output:</h3>
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<textarea id="shared" cols="80" rows="10"></textarea>
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<h3>Service Worker output:</h3>
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<textarea id="service" cols="80" rows="10"></textarea>
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</body>
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</html>

‎web-workers/worker-playground/method-throws-worker.js

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function workerMethod() {
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throw new Error("Hey! Don't call me!");
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}

‎web-workers/worker-playground/script.js

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var swReg = null;
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var useSw = null;
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navigator.serviceWorker.register("sw.js").then((reg) => {
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swReg = reg;
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useSw = reg.active || reg.waiting || reg.installing;
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});
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var taDedicated = document.getElementById("dedicated");
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var dedicatedWorker = new Worker("dedicated.js");
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dedicatedWorker.addEventListener("message", function (evt) {
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let { result } = evt.data;
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taDedicated.value = result;
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});
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var sharedWorker;
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var taShared = document.getElementById("shared");
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if ("SharedWorker" in window) {
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sharedWorker = new SharedWorker("shared.js");
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sharedWorker.port.addEventListener("message", function (evt) {
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let { result } = evt.data;
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taShared.value = result;
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});
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sharedWorker.port.start();
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} else {
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taShared.value = "Not supported by this browser.";
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}
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var taService = document.getElementById("service");
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var serviceWorker;
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navigator.serviceWorker.addEventListener("message", function (evt) {
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var { result } = evt.data;
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taService.value = result;
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});
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var curGeneration = 1;
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function evalInAll(str) {
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var payload = {
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generation: curGeneration++,
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str,
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};
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dedicatedWorker.postMessage(payload);
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if (sharedWorker) {
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sharedWorker.port.postMessage(payload);
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}
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if (useSw) {
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useSw.postMessage(payload);
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} else {
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navigator.serviceWorker.ready.then((reg) => {
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reg.active.postMessage(payload);
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});
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}
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}
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var taInput = document.getElementById("inp");
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taInput.addEventListener("keyup", function (evt) {
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evalInAll(taInput.value);
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});

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