Omitting the parameter returns the current value (getter), whereas defining the parameter sets the value (setter) and returns the instance itself for easier chaining.
GreenSock Docs
Timeline
.repeatDelay()
Gets or sets the amount of time in seconds (or frames for frames-based timelines) between repeats.
Parameters
value: Number
(default = 0
) — Omitting the parameter returns the current value (getter), whereas defining the parameter sets the value (setter) and returns the instance itself for easier chaining.
Returns : *

Details
Gets or sets the number of times that the timeline should repeat after its first iteration.
For example, if repeat
is 2 and repeatDelay
is 1, the timeline will play initially, then wait for 1 second before it repeats, then play again, then wait 1 second again before doing its final repeat. You can set the initial repeatDelay
value via the vars
parameter, like:
var tl = gsap.timeline({repeat: 2, repeatDelay: 1});
This method serves as both a getter and setter. Omitting the parameter returns the current value (getter), whereas defining the parameter sets the value (setter) and returns the instance itself for easier chaining, like myTimeline.repeat(2).yoyo(true).play();
var repeat = myTimeline.repeatDelay(); //gets current repeat value
myTimeline.repeatDelay(2); //sets repeat to 2