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Javascript prompt vs custom prompt. (chessboardjs promotion)

backstory: In chessboardjs you load the board with callback functions for specific events. Chess mechanic that gives me problem is the promotion. I need to hold my callback, prompt a user for a piece he wants to promote to, check if it is a valid move and return('snapback') or execute the move.
Stupid solution: If I prompt with classic
promoPiece = prompt();
everything works, but it looks kinda ugly.
Failed solution: But when I try to create a promise that attaches a callback to my overlay element, to get user click on specific piece I fail(i need to make function async to use promises). I try to get the piece as
async function onDrop(args)
{
..code..
promoPiece = await promoPrompt();
..code..
if(invalid())
{return 'snapback'}
}
and the promotion mechanic works, but the return snapback statement does not work because now the promise is returned instead of a string and it is not accepted with the chessboardjs...(I assumed, I did not dig into source)
Question: 1)How does prompt differ from my solution? 2)How does it work? 3)How can i create a custom promotion handler for a synchronous callback? 4)Can i use promoPrompt.then(myResolve) syntax without making onDrop() async?

It is synchronous
Natively (i.e. the code is part of the browser and exposed as an API via the prompt function)
You can't (unless it is just a wrapper around prompt but then you get the native look and feel that you dislike)
Well, yes, but the value will won't be available until that future so you can't return it to the calling function
If you want a custom UI here, then the calling function needs to be able to handle it asynchronously.

How to apply wait time when Your page javascript reloads the element

Hi i am using selenium webdriver to automate my script and i have used wait.until condition in my script to click on the delivery bttn in below html page. The problem is selenium is finding my element but since the java script reloads the certain element. And the delivery bttn only becomes clickable after reloading. And my selenium script throws "stale element reference: element is not attached to the page document". What should i do to overcome this error.
WebElement delibttn=wait.until(ExpectedConditions.elementToBeClickable(By.xpath("(//button[#class='btn-to-cart nopricetohide btn btn-primary your-catalog-deliver btn-block btn-unpadded tocart-rounded'])[1]")));
delibttn.click();
WebElement contshopping=wait.until(ExpectedConditions.elementToBeClickable(By.xpath("//a[#class='btn btn-link full-width mb-10']")));
Screenshot:

there are two ways to solve your problem.
1) Run the code with Async, that way you can 'await' a line of code, for example..
function async(test1){
await driver.findElement(By.id("");
driver.click();
});
or you can also do the following
2)
function (test1) {
let element = driver.findElement(By.id(elementId));
driver.wait(until.elementIsVisible(element), 10000).then(async () =>{
element.click();
});
This wait in number 2, is the one that i use in my code and it always works.
A very barbaric way of doing it would be to add a ridiculous wait time to check that it isn't something else showing an error similar to a wait problem
driver.sleep(10000);
or
thread.sleep(10000);
(the measurement is in milliseconds unless defined otherwise)
Please let me know if these solutions do not solve the problem.

as Jack suggested you could use async, but I always used an infinte while loop
Code i have given below is in python, but you can use the logic in java too
def wait_for_element():
val = True
while val:
web_elem = driver.find_element_by_id('id')
try:
web_elem.is_displayed()
except Exception as ex:
val = True
else:
val = False
i know infinite loop is not a better way than async, but if there are cases where you can't use async you can use this. Also keep in mind to put timeout for loop, otherwise you would looping infinitely when the page was unresponsive or has not loaded.

the reason it is still throwing this issue is because you are not handling your exceptions properly, this is a response to it still throwing stale element errors.
Add something like this to your project, if you look at the bottom of my code you will see that i have added exceptions to catch errors so it does not affect the code the way it is doing.
driver.findElement(By.id(buttonID)).then(pageElement => {
driver.wait(until.elementIsVisible(pageElement), 10000).then( () => {
pageElement.click();
next();
})
.catch(ex => {
console.log(ex.message, ex.stack)
});
}).catch(ex => {console.log(ex.message, ex.stack)});
This is the example of how i am using catches, however many promises you have in your function the more catches you will need, if you hover over an element in Visual Code / Studio you will be able to see if it throws a promise or not.

Detox Testing: Tracking down Javascript timers causing test framework to wait forever

The Detox test framework, according to the documentation TroubleShooting Synchronization mentions that the test framework will wait and only perform your next test statement when the app is "Idle".
The problem I have right now is that my app never goes idle because there's some timeout that's continuously firing. It could be in my code or third-party code.
Here's an example of the output:
As you can see something is creating a new timer every few milliseconds. What'd I'd like to do is track down which one, I can see the ids but don't know a good way to try and track down exactly where this (setTimeout) id is coming from.
I thought of wrapping the setTimeout function, but not sure what's the best way to proceed with that.
I could eliminate or at least wrap setTimout in my own code, that way, at least determining it's a third-party lib (which still doesn't help solve the problem).

You could track down setTimeouts easily with:
// DEV mode only!
function failOnTimeout(func) {
const setTimeout = f => {
throw new Error(`Executing timeout \n ${f.toString()} \n`);
};
// A small trick to change scope:
eval("(" + func.toString() + ")()");
}
So you can do:
failOnTimeout(someMysteriousFunction);
And will give you stack traces of the first timeout set in that function (synchronously). You can then comment that out and search for the next one.
But instead of trackig down all timeouts, a quick solution could be to just throw an uncatched error to end the process.

Why does timer for waits start before the steps are actually executed in a protractor test? Eventloop wrangling

tl;dr: When I run my test case, steps executed seem to work, but the test bails out early on a failure to find an element that hasn't even loaded yet. It seems like the waits I have around locating certain elements are loaded/launched as soon as the test is launched, not when the lines should actually be executed in the test case. I think this is happening because the page is barely (correctly) loaded before the "search" for the element to verify the page has loaded bails out. How do I wrangle the event loop?
This is probably a promise question, which is fine, but I don't understand what's going on. How do I implement my below code to work as expected? I'm working on creating automated E2E test cases using Jasmine2 and Protractor 5.3.0 in an Angular2 web app.
describe('hardware sets', () => {
it('TC3780:My_Test', async function() {
const testLogger = new CustomLogger('TC3780');
const PROJECT_ID = '65';
// Test Setup
browser.waitForAngularEnabled(false); // due to nature of angular project, the app never leaves zones, leaving a macrotask constantly running, thus protractor's niceness with angular is not working on our web app
// Navigate via URL to planviewer page for PROJECT_ID
await planListingPage.navigateTo(PROJECT_ID); // go to listing page for particular project
await planListingPage.clickIntoFirstRowPlans(); // go to first plan on listing page
await planViewerPage.clickOnSetItem('100'); // click on item id 100 in the plan
});
});
planViewerPage.po.ts function:
clickOnSetItem(id: string) {
element(by.id(id)).click();
browser.wait(until.visibilityOf(element(by.css('app-side-bar .card .info-content'))), 30000); // verify element I want to verify is present and visible
return expect(element(by.css('app-side-bar .card .info-content')).getText).toEqual(id); //Verify values match, This line specifically is failing.
}
This is the test case so far. I need more verification, but it is mostly done. I switched to using async function and awaits instead of the typical (done) and '.then(()=>{' statement chaining because I prefer not having to do a bunch of nesting to get things to execute in the right order. I come from a java background, so this insanity of having to force things to run in the order you write them is a bit much for me sometimes. I've been pointed to information like Mozilla's on event loop, but this line just confuses me more:
whenever a function runs, it cannot be pre-empted and will run entirely before any other code
runs (and can modify data the function manipulates).
Thus, why does it seem like test case is pre-evaluated and the timer's set off before any of the pages have been clicked on/loaded? I've implemented the solution here: tell Protractor to wait for the page before executing expect pretty much verbatim and it still doesn't wait.
Bonus question: Is there a way to output the event-loop's expected event execution and timestamps? Maybe then I could understand what it's doing.
The behavior

The code in your function is running asynchronously
clickOnSetItem(id: string) {
element(by.id(id)).click().then(function(){
return browser.wait(until.visibilityOf(element(by.css('app-side-bar .card .info-content'))), 30000);
}).then(function(){
expect(element(by.css('app-side-bar .card .info-content')).getText).toEqual(id);
}).catch(function(err){
console.log('Error: ' + err);
})
}

How can I tell when changes to jquery html() have finished?

I'm using jQuery to change the HTML of a tag, and the new HTML can be a very long string.
$("#divToChange").html(newHTML);
I then want to select elements created in the new HTML, but if I put the code immediately following the above line it seems to create a race condition with a long string where the changes that html() is making may not necessarily be finished rendering. In that case, trying to select the new elements won't always work.
What I want to know is, is there an event fired or some other way of being notified when changes to html() have finished rendering ? I came across the jQuery watch plugin, which works alright as workaround but it's not ideal. Is there a better way ?

As a commenter already mentioned, JavaScript is single threaded, so you can't get race conditions.
What may trip you up however, is the fact that the UI will not update itself based on JavaScript, until a thread is finished. This means that the entire method must finish, including all code after you call html(...), before the browser will render the content.
If your code after calling html(...) relies on the layout of the page being recalculated before continuing, you can do something like this:
$("#divToChange").html(newHTML);
setTimeout(function() {
// Insert code to be executed AFTER
// the page renders the markup
// added using html(...) here
}, 1);
Using setTimeout(...) with a time of 1 in JavaScript defers execution until after the current JavaScript code in the calling function finishes and the browser has updated the UI. This may solve your problem, though it is difficult to tell unless you can provide a reproducible example of the error you're getting.

use .ready jQuery function
$("#divToChange").html(newHTML).ready(function () {
// run when page is rendered
});

It's 7 years latter and I just ran into a scenario exactly like the one #mikel described, where I couldn't avoid a "timer based solution". So, I'm just sharing the solution I developed, in case anyone out there is still having issues with this.
I hate having setTimeouts and setIntervals in my code. So, I created a small plugin that you can put where you think it's best. I used setInterval, but you can change it to setTimeout or another solution you have in mind. The idea is simply to create a promise and keep checking for the element. We resolve the promise once it is ready.
// jquery.ensure.js
$.ensure = function (selector) {
var promise = $.Deferred();
var interval = setInterval(function () {
if ($(selector)[0]) {
clearInterval(interval);
promise.resolve();
}
}, 1);
return promise;
};
// my-app.js
function runWhenMyElementExists () {
// run the code that depends on #my-element
}
$.ensure('#my-element')
.then(runWhenMyElementExists);