Timeout with no delay causing the page to freeze

[ordo-n]

Issue summary

When the terminal buffer is full and I try to process a command a JQuery Terminal timer freezes the page for 1-2 seconds, or more.

Expected behavior

I believe that it should not freeze

Steps to reproduce

Fill the terminal buffer with lots of color
Hold ENTER down so it processes a couple of commands
You will notice this timeout has no delay so keeps firing constantly causing a freeze

Browser and OS

Edge, Chrome, Windows 11

Additional notes

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[ordo-n]

These timers are causing havoc

Heres the next one that freezes for 6 seconds

[ordo-n]

[jcubic]

The code should probably use stopTime and oneTime (from jQuery timers) instead of setTimeout.

[ordo-n]

The code should probably use stopTime and oneTime (from jQuery timers) instead of setTimeout.

Yeah. That would be preferable. What about the fix for the handler function, that's part of the jquery terminal timer and that means that all timers are susceptible to this performance issue?

[jcubic]

I would rather not modify the handler since this is 3rd party library jQuery Timers that is included jQuery Terminal.

Can you explain a bit more what issue you have with this library?

[jcubic]

I've replaced the one setTimeout with jQuery Timers and also found similar code in resize, so I've cleared the timer there as well.

[ordo-n]

I would rather not modify the handler since this is 3rd party library jQuery Timers that is included jQuery Terminal.

Can you explain a bit more what issue you have with this library?

I’m using outputLimit: 750. If I press ENTER 100 or more times, each press only processes an empty command and reprints the full color prompt. However, by this point, pressing ENTER causes the page to freeze for 1–6 seconds.

The freeze correlates with timers firing. The UI locks while queued timers execute, and input becomes unresponsive until they finish. This suggests the issue is timer-related work being triggered on each ENTER, not the output buffer being full or exceeded.

In short:

Empty ENTER presses are triggering expensive timer callbacks

Those timers block the main thread

Once this threshold is crossed, each subsequent ENTER causes a noticeable stall

[jcubic]

I don't think that this is caused by timers. It takes almost no time to execute them.

I think that if you put a lot of colors into the prompt you hit the problem of DOM nodes on the page, which slow down the page.

this is my code:

const term = $('body').terminal({}, {
    outputLimit: 750,
    prompt: '[[;red;]>][[;green;]>][[;lightblue;]>][[;yellow;]>] '
});

And I didn't even hit 750 lines. Also note that the buffer has no limits, and it's flushed after every echo that has no flush: false, so after every enter.

[jcubic]

This is my code:

https://codepen.io/jcubic/pen/azZoYKa?editors=0010

and I can't reproduce the issue. Can you create a reproduction? You can use CodePen template:

https://codepen.io/pen?template=EaYWYMp

[ordo-n]

My prompts have a bit more color than that

[ordo-n]

im using jquery 3.7.1

[jcubic]

Hm, I still get the timer in a fraction of millisecond, even if I hold the enter.

Maybe this is the issue with our computers. I have a gaming laptop.