Usage
nebula.throttle(callback, cooldown, uniqueId)
Parameters
callback
(Required) (Function) The function to run after the wait period
Default: None
cooldown
(Required) (Integer) How long (in milliseconds) between callback calls
Default: 1000
uniqueID
(Optional) (String) A unique ID to separate different Debounce function calls
Default: "No Unique ID"
Examples
Remember that the scope of "this" changes inside of the throttle function!
jQuery('#s').keyup(function(){
var oThis = jQuery(this); //Store "this" in an object to pass into the throttle
nebula.throttle(function(){
//jQuery(this) now refers to the throttle function- not the input!
var inputValue = oThis.val();
}, 1500, 'user typing in search');
});
Throttle a function and then run it once again at the end (regardless of when it happens in relation to the cooldown)
jQuery(window).on('resize', function(){
nebula.throttle(function(){
doTheThing(); //This happens every 500ms while the window is resizing (but probably not at the very end)
}, 500, 'user resizing window');
nebula.debounce(function(){
doTheThing(); //This happens only once after the event ends
}, 500, 'user resizing window');
});
Additional Notes
Very similar to debounce but where debounce happens only once at the end (or the beginning), throttle happens multiple times but limited to a set amount of time in between.
Remember: there is no guarantee that an event will trigger at the end! If the action being throttled stops half-way into the cooldown, it will not trigger again! For example, when throttling a window resize in 1 second intervals to detect media queries, you could end up with an incorrect detection if the user quickly changes their screen size in less than 1 second (or if it ends in-between the 1-second cooldown after going beyond the media query threshold).
If you need an event to happen at the end, you’ll need to use debounce. This can be done in addition to throttling, though!
Source File
Located in /assets/js/modules/utilities.js on line 483.
No Hooks
This function does not have any filters or actions available. Request one?nebula.throttle = function(callback, cooldown = 1000, uniqueID = 'No Unique ID'){
if ( !callback ){
nebula.help('nebula.throttle() requires a callback function.', '/functions/throttle/');
return false;
}
if ( typeof nebula.throttleTimers === 'undefined' ){
nebula.throttleTimers = {};
}
let context = this;
let args = arguments;
let later = function(){
if ( typeof nebula.throttleTimers[uniqueID] === 'undefined' ){ //If we're not waiting
window.requestAnimationFrame(function(){
callback.apply(context, args); //Execute callback function
nebula.throttleTimers[uniqueID] = 'waiting'; //Prevent future invocations
//After the cooldown period, allow future invocations
setTimeout(function(){
nebula.throttleTimers[uniqueID] = undefined; //Allow future invocations (undefined means it is not waiting)
}, cooldown);
});
}
};
return later();
};
Override
To override or disable this JavaScript function, simply redeclare it with the exact same function name. Remember: Some functionality is conditionally loaded via dynamic imports, so if your function is not overriding properly, try listening for a DOM event (described below).
For non-module import functions:
nebula.throttle = function(callback, cooldown, uniqueID){
//Write your own code here, leave it blank, or return false.
}
For dynamically imported module function overrides:
jQuery(window).on('load', function(){
nebula.throttle = function(callback, cooldown, uniqueID){
//Write your own code here, leave it blank, or return false.
}
});
Custom Nebula DOM events do also exist, so you could also try the following if the Window Load listener does not work:
jQuery(document).on('nebula_module_loaded', function(module){
//Note that the module variable is also available to know which module specifically was imported
if ( typeof nebula.throttle === 'function' ){
nebula.throttle = function(callback, cooldown, uniqueID){
//Write your own code here, leave it blank, or return false.
}
}
});