web worker examples

webworker.js

async function SingleWorkerExample(data, param1, param2) {
    return new Promise(resolve => {
        const blobURL = URL.createObjectURL(new Blob(['(', function() {
            onmessage = e => {
                const { data, param1, param2 } = e.data;
                // Do work with data which is a SharedArrayBuffer
                postMessage('done');
            };
        }.toString(), ')()'], { type: 'application/javascript' }));
        const worker = new Worker(blobURL);
        URL.revokeObjectURL(blobURL);
        worker.postMessage({ data, param1, param2 });
        worker.onmessage = e => {
            worker.terminate();
            resolve();
        };
    });
}
 
function ExternalFunction() {}
 
async function MultiWorkerExample(threadCount, data, param1, param2) {
    const blobURL = URL.createObjectURL(new Blob([ExternalFunction.toString(), '(', function() {
        onmessage = e => {
            const { workerIndex, threadCount, data, param1, param2 } = e.data;
            // Use workerIndex to divide work by threadCount
            // Can call ExternalFunction that is included
            postMessage('done');
        };
    }.toString(), ')()'], { type: 'application/javascript' }));
    const workers = [];
    for (let workerIndex = 0; workerIndex < threadCount; ++workerIndex) {
        workers.push(new Promise(resolve => {
            const worker = new Worker(blobURL);
            worker.postMessage({ workerIndex, threadCount, data, param1, param2 }); // Starts the computation
            worker.onmessage = e => {
                worker.terminate();
                resolve();
            };
        }));
    }
    await Promise.all(workers);
    URL.revokeObjectURL(blobURL);
}