Develop Reference

Make JS function output while function running

Javascript code
function sleep(milliseconds) {
const date = Date.now();
let currentDate = null;
do {
currentDate = Date.now();
} while (currentDate - date < milliseconds);
}
window.CP.PenTimer.MAX_TIME_IN_LOOP_WO_EXIT = 1000000;
var money = 0
var i = 0
let dollars = document.getElementById("total")
let dollarclick = document.getElementById("click1")
let autoclick = document.getElementById("buyauto")
dollarclick.addEventListener("click", clicked)
autoclick.addEventListener("click", auto)
function clicked() {
money = money + 1
dollars.innerHTML = "$"+ money.toString()
}
function auto() {
autoclick.disabled = true
console.log("function skull")
while (i<10) {
money = money + 1
dollars.innerHTML = "$"+ money.toString()
sleep(1000)
console.log(money)
i++
}
}
How to make the function output while it is running, and not let it output after the function is already finished? Keep in mind I am making a cookie clicker type game, with the auto being able to be purchased only once. Can you help me resolve this problem? The game should be able to give the points every second, and not after the function has finished. Please help me, thank you!

You can do this in an asynchronous manner.
I have used a function (setTimeoutAsync from #3 here) that resolves a promise after a timeout, and an asynchronous recursive function (nClicks(n)) that uses await for the timeout before performing the action and awaits recursion n times before returning.
Then, the asynchronous event handler just needs to disable the button and wait for nClicks(10) to complete before doing other stuff like re-enabling the button. If you don't need to do other stuff afterwards you can omit the async declaration on the handler and just call nClicks(10) without await.
const setTimeoutAsync = function(timeout) {
return new Promise((resolve) => {
setTimeout(() => {
resolve()
}, timeout)
})
}
let money = 0
const dollars = document.getElementById('total')
const tick = () => {
dollars.innerHTML = `$${++money}`
console.log('tick', dollars.innerHTML)
}
const nClicks = async(n) => {
if (n) {
// wait one second
await setTimeoutAsync(1000)
// then incriment
tick()
// wait for recursion to complete
await nClicks(--n)
}
}
const dollarclick = document.getElementById('click1')
const autoclick = document.getElementById('buyauto')
dollarclick.addEventListener('click', tick)
autoclick.addEventListener('click', async() => {
autoclick.disabled = true
// wait for 10 cycles
await nClicks(10)
autoclick.disabled = false
})
const autoclickOnce = document.getElementById('buyautoOnce')
autoclickOnce.addEventListener('click', () => {
autoclickOnce.disabled = true
nClicks(10)
})
<h1 id="total">$0</h1>
<button id="click1">+1</button>
<button id="buyauto">Auto</button>
<button id="buyautoOnce">Auto Once</button>

Javascript : Call function and wait seconds then

I feel stupid because I do not find what I want to do...
It is in PURE Javascript.
I wan't to call a function, and stop it (or kill it, or whatever) next some seconds.
Here is my actual code :
function scrollThumbnails() {
const thumbnails = document.querySelectorAll('.thumbnail');
for (thumbnail of thumbnails) {
thumbnail.classList.add('active');
await verticalSlider(thumbnail);
resetSliderPosition(thumbnail);
thumbnail.classList.remove('active');
}
scrollThumbnails();
}
async function verticalSlider(element) {
const slider = element.querySelector('.vertical-carrousel');
const max = slider.offsetHeight - slider.parentElement.offsetHeight;
var toTop = 0;
while (toTop > -max) {
await new Promise((resolve) => setTimeout(resolve, 50));
toTop--;
slider.style.top = toTop + 'px';
}
await new Promise((resolve) => setTimeout(resolve, 1000));
}
function resetSliderPosition(element) {
const slider = element.querySelector('.vertical-carrousel');
slider.style.removeProperty('top');
}
So here, i want to call 'verticalSlider' in my loop, but if it is over than 45 seconds, I want to stop it and go on the next thumbnail.
Is it possible ? Do I miss something ?
Thanks by advanced :)

This is simple example without async and await with manual timeout counter implementation.
// Function, which accepts time out value in seconds (counting from 0)
const myFunct = (timeOutSec) => {
// Get current time
const ct = Date.now();
// Set counter for example function logic
let secCounter = ct - 1000;
// Start eternal loop
while(true) {
// Get in loop time
const ilt = Date.now();
// Compare current time and in loop time
// If current time + timeout sec < in loop time, break it
if(ct + timeOutSec * 1000 < ilt) break;
// Here do main function logic in loop
// for example, console log each second
if(ilt - secCounter > 1000) {
console.log(`time ${ilt}`);
secCounter += 1000;
}
}
}
// Test running function for 4 sec
myFunct(3);
console.log(`Completed at ${Date.now()}`);
Or similar with promises
// Async timeout function
const timeout = (ms) => new Promise(resolve => setTimeout(resolve, ms));
// Promise function which accepts timout value in seconds (counting from 0)
const myPFunct = (timeOutSec) => {
return new Promise(async (resolve, reject) => {
// Current time
const ct = Date.now();
// start eternal loop
while(true) {
// In loop time
const ilt = Date.now();
// Check in-loop time, current time and timeout
if(ct + timeOutSec * 1000 < ilt) {
resolve(`completed at ${ilt}`);
break;
}
// Do something
console.log(`time: ${ilt}`);
// Wait 1 sec
await timeout(1000);
}
});
}
// Test async function
const test = async () => {
// Run myPFunct for 4 sec
const result = await myPFunct(3);
console.log(`Test function result: ${result}`);
}
// Run test function
test();

Thanks to #tarkh solution.
If someone try to do an horizontal slider like me, or something with loop, I have to modify the code (because with the source solution, the resolve goes up to all the async methods).
Here is the final solution (I have to name the loop to break it and resolve the current promise - there are maybe simplest solution ?) :
window.onload = function () {
scrollThumbnails();
}
const scrollThumbnails = async () => {
const thumbnails = document.querySelectorAll('.thumbnail');
for (thumbnail of thumbnails) {
thumbnail.classList.add('active');
await verticalSliderWithTimeout(thumbnail, 45000);
thumbnail.classList.remove('active');
}
scrollThumbnails();
}
const timeout = (ms) => new Promise(resolve => setTimeout(resolve, ms));
const verticalSliderWithTimeout = (element, timeoutDelay) => {
return new Promise(async (resolve, reject) => {
const currentTime = Date.now();
const slider = element.querySelector('.vertical-carrousel');
const max = slider.offsetHeight - slider.parentElement.offsetHeight;
var toTop = 0;
slider.style.top = toTop + 'px';
sliderLoop: while (toTop > -max) {
const inLoopTime = Date.now();
if(currentTime + timeoutDelay < inLoopTime) {
break sliderLoop;
}
await timeout(50);
toTop--;
slider.style.top = toTop + 'px';
}
resolve();
});
}
HTML code if needed (Handlebars) :
<div class="thumbnail">
<div class="photos-slider">
<div id="vertical-carrousel" class="vertical-carrousel">
{{#each this.photos}}
<img src="/image/{{../this.agency.product_type}}/{{../this.agency.id}}/{{../this.reference}}/{{urlencode this}}"
onerror="{{this}}" />
{{/each}}
</div>
</div>
</div>

I encountered the problem that the execution result of javascript is not as expected

Code is as follows：
/**
* this is calculate Timer
* #param delay Timing steps
* #returns object Provide calling interface
*/
function countTime(delay = 20) {
let millseconds = 0,
seconds = 0,
timer = null;
// calculate
function calculate() {
millseconds += delay;
if (millseconds === 1000) {
seconds += 1;
millseconds = 0;
}
}
// start the calculate
function start() {
timer = setInterval(calculate, delay);
}
// end the calculate
function end() {
clearInterval(timer);
timer = null;
}
return {
start,
end,
seconds
};
}
const obj = countTime();
obj.start();
// Wait for a while to execute
obj.end();
// execute output
console.log(obj.seconds); // always output 0
Has anyone encountered a similar issue?
I really want to know what mechanism is causing javascript, Or is there something missing in my own writing?

There are 2 problems with the code. First one is that when your function gets executed it returns object with "seconds" property. Unfortunately, that property is not being calculated each time you check against it. So basically it's a stale value. To fix that you can create a new function in your code `getSeconds:
function countTime(delay = 20) {
function getSeconds() {
return seconds;
}
...
return {
start,
end,
getSeconds
}
Another issue is that you are not waiting enough time before checking for the seconds. So you should have something like that:
const obj = countTime();
obj.start();
setTimeout(() => {
obj.end();
console.log(obj.getSeconds());
}, 3000)

How to return a Promise with setInterval()

I am trying to return a Promise object ever 1000ms, but i am not sure how to access the data returned in the Promise when it is inside a setInterval() callback.
EDIT
I appears i was not being very clear as to my intentions, so i will try and explain what it is i am trying to do. I making a count down where by the necessary calculations are are don every 1000ms based on specified end date.
Here is the code that provides the return value i would like returned as a Pormise value every 1000ms:
calculateTimeRemaining(endDate: string) {
const { secondsInDay, daysOfYear, secondsInHour, secondsInMinute } = this.unitsOfTime;
let distance: number =
(Date.parse(new Date(endDate).toString()) - Date.parse(new Date().toString())) / this.increment;
if (distance > 0) {
// Years left
if (distance >= daysOfYear * secondsInDay) {
// 365.25 * 24 * 60 * 60
this.timeRemaining.years = Math.floor(distance / (daysOfYear * secondsInDay));
distance -= this.timeRemaining.years * daysOfYear * secondsInDay;
}
// Days left
if (distance >= secondsInDay) {
// 24 * 60 * 60
this.timeRemaining.days = Math.floor(distance / secondsInDay);
distance -= this.timeRemaining.days * secondsInDay;
}
// Hours left
if (distance >= secondsInHour) {
// 60 * 60
this.timeRemaining.hours = Math.floor(distance / secondsInHour);
distance -= this.timeRemaining.hours * secondsInHour;
}
// Minutes left
if (distance >= secondsInMinute) {
// 60
this.timeRemaining.minutes = Math.floor(distance / secondsInMinute);
distance -= this.timeRemaining.minutes * secondsInMinute;
}
// Seconds left
this.timeRemaining.seconds = distance;
}
return this.timeRemaining;
}
Example:
const interval = window.setInterval(() => {
return new Promise((resolve, reject) => {
resolve('Hello');
});
}, 1000);
How to i access the Promise object with .then() afterwards?
Does not work:
interval.then((data) => console.log(data);

What you are looking for is an Observable, not a Promise. With promises, the callback you pass to then is executed at most once, so this:
interval.then((data) => console.log(data));
...will never print "Hello" more than once, even if you corrected the following mistakes in your code:
Whatever you return in a setInterval callback function is ignored.
setInterval does not return a promise, but an integer number, uniquely identifying the interval timer that was created.
On the other hand, an Observable can emit multiple events, contrary to a Promise.
There is an Observable proposal for EcmaScript, but you could create your own -- very simplified -- version of it:
class Observable {
constructor(exec) {
this.listeners = new Set;
exec({
next: (value) => this.listeners.forEach(({next}) => next && next(value)),
error: (err) => this.listeners.forEach(({error}) => error && error(err)),
complete: () => this.listeners.forEach(({complete}) => complete && complete())
});
}
subscribe(listeners) {
this.listeners.add(listeners);
return { unsubscribe: () => this.listeners.delete(listeners) }
}
}
// Create an Observable instead of a Promise;
const interval = new Observable(({next}) => {
setInterval(() => next("Hello"), 1000);
});
// Subscribe to that Observable
const subscription = interval.subscribe({ next: (data) => console.log(data) });
// Optionally use the returned subscription object to stop listening:
document.querySelector("button").addEventListener("click", subscription.unsubscribe);
<button>Stop listening</button>
Note that several JavaScript frameworks have an implementation of Observable.

Depending on what you're actually trying to do, an async iterable might do the job.
The difference is that an async iterable will only generate the next promise if you consume the last one. Intervals in JavaScript are tricky, even without promises. They try to run their callback at regular intervals, but the execution of any callback may be delayed if the interpreter is busy. That delay will not propagate, though. Also, short intervals will be throttled for background tabs.
Assuming your code is always waiting to consume the async iterable (e.g. in a for…of loop), you could do this:
function delay(t) {
return new Promise(resolve => setTimeout(resolve, t))
}
async function *interval(t) {
while(true) {
let now = Date.now()
yield "hello"
await delay(now - Date.now() + t)
}
}
for await(const greeting of interval(1000)) console.log(greeting)

For interval you can define the interval function like this
function interval() {
return new Promise(function(resolve, reject) {
setInterval(function() {
resolve('Hello');
}, 1000)
})
};
For interval you can use this:
way 1:
interval().then((x) => {
console.log(x);
})
way 2:
const intervalId = setInterval(() => {
interval().then((x) => {
console.log(x);
}, 1000)
})
This is just for stop the interval function after some time.
you must clear the interval if you does not need it more.
setTimeout(() => {
clearInterval(intervalId);
}, 10000);

I'm not sure if this will help but; Any function can be made into a promise and the alternative syntax [async keyword] might be useful for you in this case.
async function test() {
return "hello";
}
test().then( returned => console.log(returned)) // logs hello
setInterval() however does not return a return value rather it returns a "handle".
handle = window . setInterval( handler [, timeout [, arguments ] ] )
...
https://www.w3.org/TR/2011/WD-html5-author-20110705/spec.html#timers
You can, however, make promises from an setinterval ...
interval = window.setInterval(makepromise,1000)
async function makepromise() {
console.log("hello");
}
// or
interval = window.setInterval(async function () {console.log("hello");},1000)
But there is no place for a then then. We are back to callbacks, which we were trying to avoid! But there is functionality perhaps that we can use await within this function.
Better to make your calculateTimeRemaining to a promise And then you can use the then on the interval.
interval = window.setInterval(gameloop,1000);
function gameloop(endDate: string) {
calculateTimeRemaining(endDate: string).then(
//
// my then code goes here.
//
)
}
async calculateTimeRemaining(endDate: string) {
const { secondsInDay, daysOfYear, secondsInHour, secondsInMinute } = this.unitsOfTime;
let distance: number =
(Date.parse(new Date(endDate).toString()) - Date.parse(new Date().toString())) / this.increment;
if (distance > 0) {
// Years left
if (distance >= daysOfYear * secondsInDay) {
// 365.25 * 24 * 60 * 60
this.timeRemaining.years = Math.floor(distance / (daysOfYear * secondsInDay));
distance -= this.timeRemaining.years * daysOfYear * secondsInDay;
}
// Days left
if (distance >= secondsInDay) {
// 24 * 60 * 60
this.timeRemaining.days = Math.floor(distance / secondsInDay);
distance -= this.timeRemaining.days * secondsInDay;
}
// Hours left
if (distance >= secondsInHour) {
// 60 * 60
this.timeRemaining.hours = Math.floor(distance / secondsInHour);
distance -= this.timeRemaining.hours * secondsInHour;
}
// Minutes left
if (distance >= secondsInMinute) {
// 60
this.timeRemaining.minutes = Math.floor(distance / secondsInMinute);
distance -= this.timeRemaining.minutes * secondsInMinute;
}
// Seconds left
this.timeRemaining.seconds = distance;
}
return this.timeRemaining;
}
However, the value of promises is to avoid callback hell with an excessively complex call back scheme ... where the code is calling back, from call backs, from call backs, etc, etc, etc.
Promises do not operate in a 2nd operating system thread like a webworker. So unless you are attempting to clean up callbacks to make code readable or are actually waiting for something there is no benefit to make use of promises.
setInterval is a clean callback. The Gameloop example is not easier to read and understand because a promise was used. I would suggest in this case it is harder to read. at this point ... unless there are other awaits within the loop or a series of promises that do not need to run synchronously;

As already mentioned in the comments that you can not return promises on intervals, but you can keep them in a global object and use later,
const jobs = []
const interval = setInterval(() => {
if(jobs.length == 10) {
clearInterval(interval);
}
let job = Promise.resolve('new job created');
jobs.push(job);
console.log('job created')
}, 1000);
setTimeout(() => {
Promise.all(jobs).then(data => console.log(data))
}, 1000*15);

setInterval already return an integer which is useful to cancel this interval, using clearInterval.
const promise = new Promise((resolve, reject) => {
resolve('Hello');
});
Then use it like
promise.then((result) => {
console.log(result) // Says 'Hello' and will not resolve another value if we call it as it has already been resolved
})
Maybe this is what you tried to achieve.
If you want to call it with an interval of 1000 ms.
const getPromiseInstance = () => new Promise((resolve, reject) => {
resolve(Math.random());
});
setInterval(() => {
getPromiseInstance().then((result) => {
console.log(result)
})
}, 1000)
You should take a look to Observable, maybe it will fit your needs

How do I make a running total of a variable that changes in JavaScript due to live data?

I need to measure how long the following code calls the vibrate function in seconds and display the seconds which I have working. However, I don't know how to create a running total so that every time vibrate() is called, it both measures the length in seconds and then adds this to a running total.
function goodValue() {
startTime = new Date()
string1 = 'GOOD!!! :)'
displayValue('Angles', string1)
}
var startTime = {}
function badValue() {
var endTime = new Date()
vibrate1(1500)
string2 = 'BAD!!! :('
displayValue('Angles', string2)
var timeDiff = endTime - startTime //in ms
// strip the ms
timeDiff /= 1000
// get seconds
seconds = Math.round(timeDiff);
displayValue('TotalTime', + seconds);
}

This should now work. It's assuming that you call goodAngle() when the app recognizes a good angle, and badAngle() when the app recognizes a bad angle.
var totalTime = 0
var startTime = false
function goodAngle() {
if (startAngle) {
timeDiff = (Date.now() - startTime) / 1000
console.log('timeDiff: %s seconds', timeDiff)
totalTime += timeDiff
console.log('total timeDiff: %s seconds', timeDiff)
string1 = 'GOOD!!! :)'
displayValue('Angles', string1)
displayValue('BadPostureTime', Math.round(timeDiff))
startTime = false // So it can't be called again unless there's a badAngle first
}
}
function badAngle() {
if (!startTime) {
// Only set startTime if there isn't a current timer running
startTime = Date.now()
vibrate1(1500)
string2 = 'BAD!!! :('
displayValue('Angles', string2)
}
}

Skip to the expanded code snippet for the answer to this question. The rest of the examples address measuring other related metrics.
Measuring Each Individual Time
If you want to measure a function's execution time, you can wrap it in another function that uses console.time() and console.timeEnd():
function measure (fn, label = fn.name) {
return function () {
try {
console.time(label)
return fn.apply(this, arguments)
} finally {
console.timeEnd(label)
}
}
}
function delay (ms) {
const now = Date.now()
while (Date.now() - now < ms) { }
}
// wrap the function that needs to be tested
const timedDelay = measure(delay)
timedDelay(100)
timedDelay(10)
This measure() function has a few nice features:
The original function's return value is always preserved
The original function's thrown error is always preserved
If the original function throws an error, the time taken is still logged
The optional label argument is used to label the time that appears in the console
The label defaults to the name of the original function
The original function receives the context and arguments exactly as they were passed
To measure asynchronous functions, you can use the following, which can handle concurrent calls by incrementing a number used within the label in addition to the features above:
function measureAsync (fn, name = fn.name) {
let index = 0
return async function () {
const label = `${name} (${++index})`
try {
console.time(label)
return await fn.apply(this, arguments)
} finally {
console.timeEnd(label)
}
}
}
function delay (ms) {
return new Promise(resolve => {
setTimeout(resolve, ms)
})
}
// wrap the async function that needs to be tested
const timedDelay = measureAsync(delay)
timedDelay(1000)
timedDelay(100)
timedDelay(500)
Measuring Total Time
Using the above two implementations, you can modify them with the Performance API to measure cumulative time instead:
Synchronous
function measureTotal (fn, label = fn.name) {
return Object.assign(function measured () {
try {
performance.mark(label)
return fn.apply(this, arguments)
} finally {
performance.measure(label, label)
const [{ duration }] = performance.getEntriesByName(label, 'measure')
const total = measured.total += duration
performance.clearMarks(label)
performance.clearMeasures(label)
console.log(`${label}: ${total.toFixed(3)}ms`)
}
}, {
total: 0
})
}
function delay (ms) {
const now = Date.now()
while (Date.now() - now < ms) { }
}
// wrap the function that needs to be tested
const timedDelay = measureTotal(delay)
timedDelay(100)
timedDelay(10)
timedDelay(50)
console.log('total:', timedDelay.total)
Asynchronous
function measureTotalAsync (fn, name = fn.name) {
let index = 0
return Object.assign(async function measured () {
const label = `${name} (${++index})`
try {
performance.mark(label)
return await fn.apply(this, arguments)
} finally {
performance.measure(label, label)
const [{ duration }] = performance.getEntriesByName(label, 'measure')
const total = measured.total += duration
performance.clearMarks(label)
performance.clearMeasures(label)
console.log(`${label}: ${total.toFixed(3)}ms`)
}
}, {
total: 0
})
}
function delay (ms) {
return new Promise(resolve => {
setTimeout(resolve, ms)
})
}
// wrap the async function that needs to be tested
const timedDelay = measureTotalAsync(delay)
Promise.all([
timedDelay(1000),
timedDelay(100),
timedDelay(500)
]).finally(() => {
console.log('total:', timedDelay.total)
})
References
performance.mark()
performance.measure()
performance.getEntriesByName()

It is hard to tell what your code is supposed to do but I would advise making
a function which would wrap around your vibrate1 implementation.
The measureTime function takes a function as an argument (in your case vibrate) and
returns a function which has a property totalTime that records the execution
time. Note that it uses performance.now() instead of a Date object. See
https://developer.mozilla.org/fr/docs/Web/API/Performance/now for reference.
function measureTime(fn) {
const returnedFn = function measuredFunction (arg) {
const start = performance.now();
fn(arg);
const end = performance.now();
returnedFn.totalTime = returnedFn.totalTime + ((end - start) / 1000);
};
returnedFn.totalTime = 0;
return returnedFn;
}
const measuredVibrate = measureTime(vibrate1);
displayValue(measuredVibrate.totalTime);