193 lines
No EOL
3.8 KiB
JavaScript
193 lines
No EOL
3.8 KiB
JavaScript
import { loadScript } from '../utils/loader.js'
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/**
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* Manages loading and registering of reveal.js plugins.
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*/
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export default class Plugins {
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constructor() {
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// Flags our current state (idle -> loading -> loaded)
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this.state = 'idle';
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// An id:instance map of currently registed plugins
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this.registeredPlugins = {};
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this.asyncDependencies = [];
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}
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/**
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* Loads the dependencies of reveal.js. Dependencies are
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* defined via the configuration option 'dependencies'
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* and will be loaded prior to starting/binding reveal.js.
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* Some dependencies may have an 'async' flag, if so they
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* will load after reveal.js has been started up.
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*/
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load( dependencies ) {
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this.state = 'loading';
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return new Promise( resolve => {
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let scripts = [],
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scriptsToLoad = 0;
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dependencies.forEach( s => {
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// Load if there's no condition or the condition is truthy
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if( !s.condition || s.condition() ) {
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if( s.async ) {
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this.asyncDependencies.push( s );
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}
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else {
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scripts.push( s );
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}
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}
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} );
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if( scripts.length ) {
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scriptsToLoad = scripts.length;
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// Load synchronous scripts
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scripts.forEach( s => {
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loadScript( s.src, () => {
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if( typeof s.callback === 'function' ) s.callback();
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if( --scriptsToLoad === 0 ) {
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this.initPlugins().then( resolve );
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}
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} );
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} );
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}
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else {
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this.initPlugins().then( resolve );
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}
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} );
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}
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/**
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* Initializes our plugins and waits for them to be ready
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* before proceeding.
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*/
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initPlugins() {
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return new Promise( resolve => {
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let pluginsToInitialize = Object.keys( this.registeredPlugins ).length;
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// If there are no plugins, skip this step
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if( pluginsToInitialize === 0 ) {
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this.loadAsync().then( resolve );
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}
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// ... otherwise initialize plugins
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else {
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let afterPlugInitialized = () => {
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if( --pluginsToInitialize === 0 ) {
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this.loadAsync().then( resolve );
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}
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};
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for( let i in this.registeredPlugins ) {
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let plugin = this.registeredPlugins[i];
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// If the plugin has an 'init' method, invoke it
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if( typeof plugin.init === 'function' ) {
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let callback = plugin.init();
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// If the plugin returned a Promise, wait for it
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if( callback && typeof callback.then === 'function' ) {
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callback.then( afterPlugInitialized );
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}
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else {
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afterPlugInitialized();
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}
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}
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else {
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afterPlugInitialized();
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}
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}
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}
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} )
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}
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/**
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* Loads all async reveal.js dependencies.
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*/
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loadAsync() {
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this.state = 'loaded';
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if( this.asyncDependencies.length ) {
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this.asyncDependencies.forEach( s => {
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loadScript( s.src, s.callback );
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} );
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}
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return Promise.resolve();
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}
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/**
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* Registers a new plugin with this reveal.js instance.
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*
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* reveal.js waits for all regisered plugins to initialize
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* before considering itself ready, as long as the plugin
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* is registered before calling `Reveal.initialize()`.
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*/
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registerPlugin( id, plugin ) {
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if( this.registeredPlugins[id] === undefined ) {
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this.registeredPlugins[id] = plugin;
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// If a plugin is registered after reveal.js is loaded,
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// initialize it right away
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if( this.state === 'loaded' && typeof plugin.init === 'function' ) {
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plugin.init();
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}
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}
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else {
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console.warn( 'reveal.js: "'+ id +'" plugin has already been registered' );
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}
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}
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/**
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* Checks if a specific plugin has been registered.
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*
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* @param {String} id Unique plugin identifier
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*/
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hasPlugin( id ) {
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return !!this.registeredPlugins[id];
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}
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/**
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* Returns the specific plugin instance, if a plugin
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* with the given ID has been registered.
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*
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* @param {String} id Unique plugin identifier
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*/
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getPlugin( id ) {
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return this.registeredPlugins[id];
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}
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getRegisteredPlugins() {
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return this.registeredPlugins;
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}
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} |