Javascript: calling asynchronously-initialized libraries from synchronous code

With the power of await, this isn't so difficult: let nacl, scrypt; function main() { /* Synchronous code that calls nacl and scrypt */ } (async () => { [nacl, scrypt] = await Promise.all([new Promise(nacl_factory.instantiate), new Promise(scrypt_module_factory)]); return main(); })();

Auto-updating userscripts hosted on Github Gist

In the process of crafting this small set of improvements to Advance Wars By Web, I found out about the proper URL for auto-updating userscripts which are hosted on Microsoft's "Gist" service: // @updateURL������/����������������/raw/�����.user.js This will always redirect to the latest version of the file.

Javascript: getElementByXPath

function getElementByXPath(path, context=null, document=null, namespaceResolver=null, first_ordered=true) {
  if (context === null) context = window.document.documentElement;
  if (document === null) document = context.ownerDocument;
  if (namespaceResolver === null) namespaceResolver = document.createNSResolver(context);
  const result = document.evaluate(path, context, namespaceResolver, first_ordered ? XPathResult.FIRST_ORDERED_NODE_TYPE : XPathResult.ANY_UNORDERED_NODE_TYPE, null);
  return result.singleNodeValue || null;

Basic JS Async Cookbook

function asleep(delay) { return new Promise(resolve => setTimeout(resolve, delay)); } // Usage: await asleep(1000); function aalert(message) { return new Promise( resolve => resolve(alert(message)) ); } function aconfirm(message) { return new Promise( resolve => resolve(confirm(message)) ); } function aprompt(message, deflt) { return new Promise( resolve => resolve(prompt(message, deflt)) ); } // Usage: await aalert("The task will begin as soon as you press OK.") ; do_task(); aalert("The task will begin as …

JS: Tail-call optimized recursive setTimeout

If you're writing some code on a time-delayed-loop in JavaScript, there are 2 main options: setInterval setTimeout, recursively However, each has a potential downside: setInterval schedules the code to run at the given interval, regardless of whether the last invocation has completed. This means that, if the function takes longer than the delay to execute, it'll schedule the next invocation before the current invocation is finished, which can lead …