12
rant1ng
2y

I need to delay execution of code in a for loop, how do I do that?

PHP: Sleep(3000)

Javascript:
const waitFor = (ms) => new Promise(r => setTimeout(r, ms))
const asyncForEach = (array, callback) => {
for (let index = 0; index < array.length; index++) {
await callback(array[index], index, array)
}
}

const start = async () => {
await asyncForEach([1, 2, 3], async (num) => {
await waitFor(50)
console.log(num)
})
console.log('Done')
}

start()

Fuck you Javascript

Comments
  • 11
    Learn more fuck less.
  • 16
    Maybe it's hard because you shouldn't be doing it.
  • 15
    I'm amazed how you don't even need to write a for loop in php to get a for loop.

    Also, any reason you need to wait for 50 minutes?
  • 8
    Aint it just setTimeout(420) ?
  • 9
    @ganjaman setTimeout(callback, ms);

    The reason why there's a callback is because it needs to be non-blocking. A sleep function like in PHP wouldn't work since it would result in the event loop being blocked, which would mean you wouldn't be able to use the page at all since the event loop also draws the content and stuff.

    Also made a codepen https://codepen.io/anon/pen/xyXyYW

    (Also the fact that the callback is in the beginning is dumb as hell)
  • 8
    Your examples are very lopsided.
  • 7
    Hmmm blocking wait in single-threaded JavaScript - what could possibly go wrong?!
  • 4
    A bit cherry picking there buddy
  • 1
    @inaba oh yeah, i just put an empty log in the callback. Man i havent used js in like a year
  • 1
    I found that on github in my lazy, I'm tired of working today way that I attempted to solve this problem

    Was kind of similar to a lot of other examples that I didn't feel like trying to understand.

    I get it, Javascript is a delicate, asynch flower.
    k. I'll tackle this in the morning.

    I still hate it.

    sue me.
  • 1
    You don't need the asyncForEach thing, you can just use a for loop:

    for (const num of [1,2,3]) {

    }

    or, if you prefer, Promise.all + map:

    await Promise.all([1,2,3].map(num => {

    }))
  • 1
    @Fast-Nop that's not a blocking wait, it yields to the event loop
  • 1
    @rant1ng or you could just admit your first post was dumb lmao
  • 1
    @inaba hey!

    fine.

    solved it by using current time

    so there

    eat it, Javascript
  • 1
    @inaba PHP doesn't have an event loop. Sleeping just pauses execution.
  • 1
    @ganjaman 420 msecs is a bit fast for rolling one up though... Or do I just suck at rolling?
  • 1
    @tbodt the OP wanted to have something like Sleep(3000) in JavaScript, which would be a blocking wait. That was my question what could possibly go wrong with such an approach, and that's why the waiting isn't done like that in JS. Of course, asynchronous wait is a bit more code than Sleep(3000). For good reason.
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