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feat: add a function to throttle scrolling events #564

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feat: add a function to throttle scrolling events #564

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17 changes: 15 additions & 2 deletions src/remark/controllers/inputs/mouse.js
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Original file line number Diff line number Diff line change
Expand Up @@ -6,6 +6,17 @@ exports.unregister = function (events) {
removeMouseEventListeners(events);
};

function throttle(events, eventName) {
var timestamp = null;
return function() {
var now = Date.now();
if (timestamp === null || now - timestamp > 100) {
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@peterj peterj Jan 3, 2020

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What do you think about making this optional?

Right now you can enable/disable scrolling - would it make sense to add an option to throttle and the time value e.g.:

var slideshow = remark.create({
  navigation: {
      scrollThrottle: 100,  // default value would be 0 or the same behavior we have today.
  }
});

events.emit(eventName);
}
timestamp = now;
};
}

function addMouseEventListeners (events, options) {
if (options.click) {
events.on('click', function (event) {
Expand All @@ -27,13 +38,15 @@ function addMouseEventListeners (events, options) {
});
}

var throttledPrev = throttle(events, 'gotoPreviousSlide');
var throttledNext = throttle(events, 'gotoNextSlide');
if (options.scroll !== false) {
var scrollHandler = function (event) {
if (event.wheelDeltaY > 0 || event.detail < 0) {
events.emit('gotoPreviousSlide');
throttledPrev();
}
else if (event.wheelDeltaY < 0 || event.detail > 0) {
events.emit('gotoNextSlide');
throttledNext();
}
};

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