emscriptenRunner.js

const run = (glue, stdin, stdout, stderr) => {
    const iframe = document.createElement('iframe');
    iframe.setAttribute('style', 'display: none; ');
    iframe.src = 'about:blank';
    iframe.onload = () => {
        iframe.contentWindow.Module = {
            preRun: [
                () => {
                    const _in = new TextEncoder('ascii').encode(stdin).values();
                    iframe.contentWindow.FS.init(() => _in.next().value, null, null);
                },
            ],
            postRun: [
                () => document.body.removeChild(iframe),
            ],
            print: (...arguments) => stdout(arguments.join(' ')),
            printErr: (...arguments) => stderr(arguments.join(' ')),
            setStatus: console.log,
            monitorRunDependencies: (left) => {
                this.totalDependencies = Math.max(this.totalDependencies || 0, left);
                console.log(left ? 'Preparing... (' + (this.totalDependencies - left) + '/' + this.totalDependencies + ')' : 'All downloads complete.');
            },
        };

        const script = document.createElement('script');
        script.setAttribute('async', '');
        script.src = glue;
        iframe.contentDocument.body.appendChild(script);
    }
    document.body.appendChild(iframe);
};