javascript-callback/

[utterances-bot]

Everything About Callback Functions in JavaScript

The callback is a function being called by another function, either synchronously or asynchronously.

https://dmitripavlutin.com/javascript-callback/

[vijeysrc]

setTimeout(callback, 0) execute the callback asynchronously

[panzerdp]

setTimeout(callback, 0) execute the callback asynchronously

Exactly!

[srk1195]

setTimeout(cb,0) will be asynchronous, since the function fundamentally cannot behave differently upon different delays supplied.

[hopecookies]

love all the content! here's a small typo under section 4, the first sentence:

"The special keyword async placed before the function definition creates an asynchornous function:" misspelled asynchronous.

still, love all the content. keep them coming!

[baspinarenes]

Simple and clear explanation. Thanks!

[panzerdp]

Simple and clear explanation. Thanks!

Thanks @baspinarenes!

[SilverWings47]

Can you explain to me how does the arrow function ({ login }) => login work in " users.map(({ login }) => login);" Is login an object ?? Thank you.

[ghkerh]

Hello Dmitri! Excellent explanation of the "callback" question! But in the array.map function, is it possible to integrate an additional callback to intervene between each item of the array? If not, how should I proceed then? (Because map will not wait for my setTimeout and other braking attempts!)

[panzerdp]

Hello Dmitri! Excellent explanation of the "callback" question! But in the array.map function, is it possible to integrate an additional callback to intervene between each item of the array? If not, how should I proceed then? (Because map will not wait for my setTimeout and other braking attempts!)

Hi @ghkerh! Can you share some code?

[ghkerh]

Hi Dmitri! Thank you for your answer!!! I have on the screen 5 rows of 11 thumbnails each. By 'callback' I treat each row separately to get special effects (by changing the CSS class of each thumbnail). But all the thumbnails of the same row change at the same time. Impossible to process them one by one...

Code (original function called: runThumbs): function runThumbs() { if ((document.getElementById('size').value === '1') && (vG.anim)) { let classMP, u = 0; vG.nroRow = 0; moveThumbs(animeThumbs); } }

function isEven(n) { n = Number(n); return n === 0 || !!(n && !(n % 2)); }

function moveThumbs(fct) { let classMP; if (isEven(vG.nroRow)) classMP = 'thumbEffectM'; else classMP = 'thumbEffectP'; vG.classMP = classMP; if (vG.nroRow < 5) { fct(); vG.nroRow++; setTimeout(function() {moveThumbs(fct);}, 150); // This works perfectly for the rows! } else return; }

function animeThumbs() { function fctCB(idTh) { document.getElementById(idTh).classList.add(classMP); } function fcuCB(idTh) { document.getElementById(idTh).classList.remove(classMP); } let classMP = vG.classMP; let varR = 'rowmult' + vG.nroRow.toString(); const row = document.getElementById(varR); if (row) { // 1. let thumbs = []; for (let i = 0; i < row.children.length; i++) {thumbs.push(document.getElementById(row.id).children[i].id);} thumbs.map(fctCB); // Here I would like clearly distinguish the movement of each thumbnail on a row. // 2. setTimeout(function() {thumbs.map(fcuCB);}, 1000); // ...and here } }

Le mer. 5 janv. 2022 à 18:09, Dmitri Pavlutin @.***> a écrit :

Hello Dmitri! Excellent explanation of the "callback" question! But in the array.map function, is it possible to integrate an additional callback to intervene between each item of the array? If not, how should I proceed then? (Because map will not wait for my setTimeout and other braking attempts!)

Hi @ghkerh https://github.com/ghkerh! Can you share some code?

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[RostoRM]

"The synchronous callbacks are executed at the same time as the higher-order function that uses the callback."

setTimeout( () => console.log('This is callback'), 0);

I thought this was synchronous callbacks...as it's execute at the same time as the higher-order function... Can anyone explain why is this asynchronously?

I think this was asynchronously callback like this:

setTimeout( () => console.log('This is callback'), 3000);

[AdeetyAraJsaH]

users.map(({ login }) => login) I couldn't get this , can you explain inside code of map function?