避免在间隔开始时执行setInterval（）

Question

I've noticed that the setInterval() function actually runs (as in, takes in the values) at the beginning of the interval, then waits and returns the result at the end of the interval. If the values change mid-interval, it's still going to execute as it would have had in the beginning. This is causing unwanted behavior in my slider. Is there a way to force setInterval() to do both at the very end of the interval? Preferably without jQuery.

EDIT: While I was converting my code to post here, the issue resolved itself. Turns out it had little to do with my question. I'm sorry, I'll be sure to post code next time. THANK YOU FOR THE ANSWERS! :) Hopefully they help someone in the future, as I couldn't find a question like this anyway.

Answer 1

Yes. Use setTimeout recursively, which is generally better idea.

 function doSomething() { setTimeout(function () { console.log('something') doSomething() }, 2000) } console.log('start') doSomething() 

Answer 2

You should post some of your code. I'm not totally sure if this is your problem, but if you look at this:

setInterval(() => {
  var message = 'ok';
  console.log(message);
}, 1000);

message = 'not ok';

The 'message' variable defined inside of setInterval is scoped to the function being passed into setInterval. So when I attempt to change the variable outside of that scope, it won't work. I'm actually accidentally creating a new variable on the window object.

However, if I do this:

var message = 'ok';

setInterval(() => {
  console.log(message);
}, 1000);

message = 'not ok';

The 'message' variable is successfully changed and setInterval will call the variable with that change.

Answer 3

You can bind the variables you need on the window object.

window.myVariable = 'Important String';

setInterval(function() {
  doSomethingWith(window.myVariable);
}, 2000);

// Variable is changed
window.myVariable = 'Less Important String';