view release on metacpan or  search on metacpan

share/revealjs/js/controllers/fragments.js  view on Meta::CPAN

import { extend, queryAll } from '../utils/util.js'

/**
 * Handles sorting and navigation of slide fragments.
 * Fragments are elements within a slide that are
 * revealed/animated incrementally.
 */
export default class Fragments {

	constructor( Reveal ) {

		this.Reveal = Reveal;

	}

	/**
	 * Called when the reveal.js config is updated.
	 */
	configure( config, oldConfig ) {

		if( config.fragments === false ) {
			this.disable();
		}
		else if( oldConfig.fragments === false ) {
			this.enable();
		}

	}

	/**
	 * If fragments are disabled in the deck, they should all be
	 * visible rather than stepped through.
	 */
	disable() {

		queryAll( this.Reveal.getSlidesElement(), '.fragment' ).forEach( element => {
			element.classList.add( 'visible' );
			element.classList.remove( 'current-fragment' );
		} );

	}

	/**
	 * Reverse of #disable(). Only called if fragments have
	 * previously been disabled.
	 */
	enable() {

		queryAll( this.Reveal.getSlidesElement(), '.fragment' ).forEach( element => {
			element.classList.remove( 'visible' );
			element.classList.remove( 'current-fragment' );
		} );

	}

	/**
	 * Returns an object describing the available fragment
	 * directions.
	 *
	 * @return {{prev: boolean, next: boolean}}
	 */
	availableRoutes() {

		let currentSlide = this.Reveal.getCurrentSlide();
		if( currentSlide && this.Reveal.getConfig().fragments ) {
			let fragments = currentSlide.querySelectorAll( '.fragment:not(.disabled)' );
			let hiddenFragments = currentSlide.querySelectorAll( '.fragment:not(.disabled):not(.visible)' );

			return {
				prev: fragments.length - hiddenFragments.length > 0,
				next: !!hiddenFragments.length
			};
		}
		else {
			return { prev: false, next: false };
		}