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authorDavid Thompson <dthompson2@worcester.edu>2024-06-24 13:49:08 -0400
committerDavid Thompson <dthompson2@worcester.edu>2024-06-24 13:52:17 -0400
commitd283f7e661e14d6ae1881fe803e5b4f1ed0689ff (patch)
tree84d3811c6dcb7d7f02aecadad7b2dfacce83bd4f /2024-06-18-guix-social/reveal.js/js/controllers/location.js
parent3d9dcd3099fb252fa35697148fbbd541eb9eecc9 (diff)
Add 2024 Guix social talk.HEADmaster
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+/**
+ * Reads and writes the URL based on reveal.js' current state.
+ */
+export default class Location {
+
+ // The minimum number of milliseconds that must pass between
+ // calls to history.replaceState
+ MAX_REPLACE_STATE_FREQUENCY = 1000
+
+ constructor( Reveal ) {
+
+ this.Reveal = Reveal;
+
+ // Delays updates to the URL due to a Chrome thumbnailer bug
+ this.writeURLTimeout = 0;
+
+ this.replaceStateTimestamp = 0;
+
+ this.onWindowHashChange = this.onWindowHashChange.bind( this );
+
+ }
+
+ bind() {
+
+ window.addEventListener( 'hashchange', this.onWindowHashChange, false );
+
+ }
+
+ unbind() {
+
+ window.removeEventListener( 'hashchange', this.onWindowHashChange, false );
+
+ }
+
+ /**
+ * Returns the slide indices for the given hash link.
+ *
+ * @param {string} [hash] the hash string that we want to
+ * find the indices for
+ *
+ * @returns slide indices or null
+ */
+ getIndicesFromHash( hash=window.location.hash, options={} ) {
+
+ // Attempt to parse the hash as either an index or name
+ let name = hash.replace( /^#\/?/, '' );
+ let bits = name.split( '/' );
+
+ // If the first bit is not fully numeric and there is a name we
+ // can assume that this is a named link
+ if( !/^[0-9]*$/.test( bits[0] ) && name.length ) {
+ let slide;
+
+ let f;
+
+ // Parse named links with fragments (#/named-link/2)
+ if( /\/[-\d]+$/g.test( name ) ) {
+ f = parseInt( name.split( '/' ).pop(), 10 );
+ f = isNaN(f) ? undefined : f;
+ name = name.split( '/' ).shift();
+ }
+
+ // Ensure the named link is a valid HTML ID attribute
+ try {
+ slide = document
+ .getElementById( decodeURIComponent( name ) )
+ .closest('.slides section');
+ }
+ catch ( error ) { }
+
+ if( slide ) {
+ return { ...this.Reveal.getIndices( slide ), f };
+ }
+ }
+ else {
+ const config = this.Reveal.getConfig();
+ let hashIndexBase = config.hashOneBasedIndex || options.oneBasedIndex ? 1 : 0;
+
+ // Read the index components of the hash
+ let h = ( parseInt( bits[0], 10 ) - hashIndexBase ) || 0,
+ v = ( parseInt( bits[1], 10 ) - hashIndexBase ) || 0,
+ f;
+
+ if( config.fragmentInURL ) {
+ f = parseInt( bits[2], 10 );
+ if( isNaN( f ) ) {
+ f = undefined;
+ }
+ }
+
+ return { h, v, f };
+ }
+
+ // The hash couldn't be parsed or no matching named link was found
+ return null
+
+ }
+
+ /**
+ * Reads the current URL (hash) and navigates accordingly.
+ */
+ readURL() {
+
+ const currentIndices = this.Reveal.getIndices();
+ const newIndices = this.getIndicesFromHash();
+
+ if( newIndices ) {
+ if( ( newIndices.h !== currentIndices.h || newIndices.v !== currentIndices.v || newIndices.f !== undefined ) ) {
+ this.Reveal.slide( newIndices.h, newIndices.v, newIndices.f );
+ }
+ }
+ // If no new indices are available, we're trying to navigate to
+ // a slide hash that does not exist
+ else {
+ this.Reveal.slide( currentIndices.h || 0, currentIndices.v || 0 );
+ }
+
+ }
+
+ /**
+ * Updates the page URL (hash) to reflect the current
+ * state.
+ *
+ * @param {number} delay The time in ms to wait before
+ * writing the hash
+ */
+ writeURL( delay ) {
+
+ let config = this.Reveal.getConfig();
+ let currentSlide = this.Reveal.getCurrentSlide();
+
+ // Make sure there's never more than one timeout running
+ clearTimeout( this.writeURLTimeout );
+
+ // If a delay is specified, timeout this call
+ if( typeof delay === 'number' ) {
+ this.writeURLTimeout = setTimeout( this.writeURL, delay );
+ }
+ else if( currentSlide ) {
+
+ let hash = this.getHash();
+
+ // If we're configured to push to history OR the history
+ // API is not available.
+ if( config.history ) {
+ window.location.hash = hash;
+ }
+ // If we're configured to reflect the current slide in the
+ // URL without pushing to history.
+ else if( config.hash ) {
+ // If the hash is empty, don't add it to the URL
+ if( hash === '/' ) {
+ this.debouncedReplaceState( window.location.pathname + window.location.search );
+ }
+ else {
+ this.debouncedReplaceState( '#' + hash );
+ }
+ }
+ // UPDATE: The below nuking of all hash changes breaks
+ // anchors on pages where reveal.js is running. Removed
+ // in 4.0. Why was it here in the first place? ¯\_(ツ)_/¯
+ //
+ // If history and hash are both disabled, a hash may still
+ // be added to the URL by clicking on a href with a hash
+ // target. Counter this by always removing the hash.
+ // else {
+ // window.history.replaceState( null, null, window.location.pathname + window.location.search );
+ // }
+
+ }
+
+ }
+
+ replaceState( url ) {
+
+ window.history.replaceState( null, null, url );
+ this.replaceStateTimestamp = Date.now();
+
+ }
+
+ debouncedReplaceState( url ) {
+
+ clearTimeout( this.replaceStateTimeout );
+
+ if( Date.now() - this.replaceStateTimestamp > this.MAX_REPLACE_STATE_FREQUENCY ) {
+ this.replaceState( url );
+ }
+ else {
+ this.replaceStateTimeout = setTimeout( () => this.replaceState( url ), this.MAX_REPLACE_STATE_FREQUENCY );
+ }
+
+ }
+
+ /**
+ * Return a hash URL that will resolve to the given slide location.
+ *
+ * @param {HTMLElement} [slide=currentSlide] The slide to link to
+ */
+ getHash( slide ) {
+
+ let url = '/';
+
+ // Attempt to create a named link based on the slide's ID
+ let s = slide || this.Reveal.getCurrentSlide();
+ let id = s ? s.getAttribute( 'id' ) : null;
+ if( id ) {
+ id = encodeURIComponent( id );
+ }
+
+ let index = this.Reveal.getIndices( slide );
+ if( !this.Reveal.getConfig().fragmentInURL ) {
+ index.f = undefined;
+ }
+
+ // If the current slide has an ID, use that as a named link,
+ // but we don't support named links with a fragment index
+ if( typeof id === 'string' && id.length ) {
+ url = '/' + id;
+
+ // If there is also a fragment, append that at the end
+ // of the named link, like: #/named-link/2
+ if( index.f >= 0 ) url += '/' + index.f;
+ }
+ // Otherwise use the /h/v index
+ else {
+ let hashIndexBase = this.Reveal.getConfig().hashOneBasedIndex ? 1 : 0;
+ if( index.h > 0 || index.v > 0 || index.f >= 0 ) url += index.h + hashIndexBase;
+ if( index.v > 0 || index.f >= 0 ) url += '/' + (index.v + hashIndexBase );
+ if( index.f >= 0 ) url += '/' + index.f;
+ }
+
+ return url;
+
+ }
+
+ /**
+ * Handler for the window level 'hashchange' event.
+ *
+ * @param {object} [event]
+ */
+ onWindowHashChange( event ) {
+
+ this.readURL();
+
+ }
+
+} \ No newline at end of file