Implement auto-animate id and restart

js/controllers/autoanimate.js

@@ -27,8 +27,16 @@ export default class AutoAnimate {
 		// Clean up after prior animations
 		this.reset();
 
-		// Ensure that both slides are auto-animate targets
-		if( fromSlide.hasAttribute( 'data-auto-animate' ) && toSlide.hasAttribute( 'data-auto-animate' ) ) {
+		let allSlides = this.Reveal.getSlides();
+		let toSlideIndex = allSlides.indexOf( toSlide );
+		let fromSlideIndex = allSlides.indexOf( fromSlide );
+
+		// Ensure that both slides are auto-animate targets with the same data-auto-animate-id value
+		// (including null if absent on both) and that data-auto-animate-restart isn't set on the
+		// physically latter slide (independent of slide direction)
+		if( fromSlide.hasAttribute( 'data-auto-animate' ) && toSlide.hasAttribute( 'data-auto-animate' )
+				&& fromSlide.getAttribute( 'data-auto-animate-id' ) === toSlide.getAttribute( 'data-auto-animate-id' ) 
+				&& !( toSlideIndex > fromSlideIndex ? toSlide : fromSlide ).hasAttribute( 'data-auto-animate-restart' ) ) {
 
 			// Create a new auto-animate sheet
 			this.autoAnimateStyleSheet = this.autoAnimateStyleSheet || createStyleSheet();
@@ -40,8 +48,7 @@ export default class AutoAnimate {
 			toSlide.dataset.autoAnimate = 'pending';
 
 			// Flag the navigation direction, needed for fragment buildup
-			let allSlides = this.Reveal.getSlides();
-			animationOptions.slideDirection = allSlides.indexOf( toSlide ) > allSlides.indexOf( fromSlide ) ? 'forward' : 'backward';
+			animationOptions.slideDirection = toSlideIndex > fromSlideIndex ? 'forward' : 'backward';
 
 			// Inject our auto-animate styles for this transition
 			let css = this.getAutoAnimatableElements( fromSlide, toSlide ).map( elements => {

js/reveal.js

@@ -1251,7 +1251,10 @@ export default function( revealElement, options ) {
 			// Note 20-03-2020:
 			// This needs to happen before we update slide visibility,
 			// otherwise transitions will still run in Safari.
-			if( previousSlide.hasAttribute( 'data-auto-animate' ) && currentSlide.hasAttribute( 'data-auto-animate' ) ) {
+			if( previousSlide.hasAttribute( 'data-auto-animate' ) && currentSlide.hasAttribute( 'data-auto-animate' )
+					&& previousSlide.getAttribute( 'data-auto-animate-id' ) === currentSlide.getAttribute( 'data-auto-animate-id' )
+					&& !( ( indexh > indexhBefore || indexv > indexvBefore ) ? currentSlide : previousSlide ).hasAttribute( 'data-auto-animate-restart' ) ) {
+
 				autoAnimateTransition = true;
 				dom.slides.classList.add( 'disable-slide-transitions' );
 			}