/**
* Detects whether the browser supports Web Workers with ES6 module syntax (`type: 'module'`).
* @module lib/util/supportsWorkerModules
* @author Frank Kudermann - alphanull
* @version 1.0.0
* @license MIT
*/
export default supportsWorkerModules;
/**
* This function attempts to create a Web Worker with an ES6 module and sends a test message to verify support.
* It creates a Worker from a Blob and attempts to run code that checks if `type: 'module'` works for Workers.
* The function uses `eval()` to run a base64-encoded Worker script since `importScripts` cannot be used with ES6 modules.
* @memberof module:lib/util/supportsWorkerModules
* @returns {Promise<boolean>} A promise that resolves to true if ES6 module Workers are supported, otherwise false.
*/
function supportsWorkerModules() {
return new Promise(resolve => {
try {
// Define the Worker code as a string (this will be base64 encoded)
const workerCode = "onmessage = function() { postMessage('Worker Done'); }",
base64Module = btoa(workerCode), // Encode the Worker code into Base64
blob = new Blob([`const code = atob('${base64Module}'); eval(code);`], { type: 'application/javascript' }), // Create a Blob containing the Worker code wrapped in eval() for execution
workerURL = URL.createObjectURL(blob), // Create a URL for the Blob and create the Worker
testWorker = new Worker(workerURL, { type: 'module' }); // Create a Worker with ES6 module type
// Set up message handler to check if the Worker module is supported
testWorker.onmessage = function() {
URL.revokeObjectURL(workerURL); // Clean up the Blob URL
testWorker.terminate(); // Terminate the Worker
resolve(true); // Resolve the Promise to indicate Worker module is supported
};
// Handle errors if the Worker fails (i.e., if modules are not supported)
testWorker.onerror = function() {
URL.revokeObjectURL(workerURL); // Clean up the Blob URL
testWorker.terminate(); // Terminate the Worker
resolve(false); // Resolve the Promise to indicate Worker module is not supported
};
// Post a test message to trigger Worker execution
testWorker.postMessage('test'); // This triggers the `onmessage` callback in the Worker
} catch {
resolve(false); // Resolve the Promise to indicate failure
}
});
}
