setTimeout导致未捕获的TypeError：number不是函数

Question

so I'm declaring blank variables outside of functions.

//To be Timeouts
var progressionTimer;
var nextTimer; 
var cycleTimer;

and then within functions

progressionTimer = setTimout(loadNextFunction, 2000);
progressionTimer();

nextTimer = setTimeout(loadOutsideFunction, 2000);
nextTimer();

//etc

however every time one of those declaration is called

nextTimer();

my console in chrome/firefox/etc fills with this

Uncaught TypeError: number is not a function

it functions absolutely as intended and clearTimeout works without issue, but the console error is just frustrating me, can anyone solve this without loosing the funcitonality and still having clearTimeout work?

Answer 1

setTimeout returns a handler, an ID that lets you reference the timeout so you can clear it with clearTimeout , which is a number.

It does not return a function that can be executed, and that is the problem, you're trying to execute the return value of setTimeout

nextTimer = setTimeout(loadOutsideFunction, 2000);
nextTimer(); // not a function, but a number referencing the timeout ?

clearTimeout(nextTimer); // works just fine