webworker from function and webworkerImageLoad

gistfile1.txt

function createWorker(f) {
    return new Worker(URL.createObjectURL(new Blob([`(${f})()`])));
}

gistfile2.txt

const worker = createWorker(() => {
    self.addEventListener('message', e => {
        let src = e.data
        fetch(src)
		.then(response => response.blob())
		.then(blob => createImageBitmap(blob))
		.then(bitmap => {
			self.postMessage({ src, bitmap }, [bitmap]);
		});
    });
});

gistfile3.txt

export default function webworkerImageLoad(src) {
    return new Promise((resolve, reject) => {
        function handler(e) {
            if (e.data.src === src) {
                worker.removeEventListener('message', handler);
                if (e.data.error) {
                    reject(e.data.error);
                }
                resolve(e.data);
            }
        }
        worker.addEventListener('message', handler);
        worker.postMessage(src);
    });
}