MediaWiki:Gadget-SelectionCounter.js：修订间差异

/* MediaWiki Gadget: SelectionCounter */
( function () {
	'use strict';

	if ( window.SelectionCounterLoaded ) {
		return;
	}
	window.SelectionCounterLoaded = true;

	mw.loader.using( [ 'jquery', 'mediawiki.util' ] ).then( function () {
		var $counter;
		var rafId = 0;
		var hideTimer = 0;
		var lastRendered = '';
		var lastShownAt = 0;
		var selecting = false;
		var canSegment = typeof Intl !== 'undefined' && typeof Intl.Segmenter === 'function';
		var segmenter = canSegment ? new Intl.Segmenter( mw.config.get( 'wgUserLanguage' ) || 'zh-cn', {
			granularity: 'grapheme'
		} ) : null;

		function getMessage( count ) {
			var lang = ( mw.config.get( 'wgUserLanguage' ) || mw.config.get( 'wgContentLanguage' ) || 'zh-cn' ).toLowerCase();
			return lang.indexOf( 'en' ) === 0 ? 'Selected ' + count + ' chars' : '已选 ' + count + ' 字';
		}

		function getSelectionText() {
			var selection = window.getSelection && window.getSelection();
			if ( !selection || selection.rangeCount === 0 || selection.isCollapsed ) {
				return '';
			}
			return selection.toString();
		}

		function countText( text ) {
			var compact = text.replace( /\s+/g, '' );
			if ( !compact ) {
				return 0;
			}
			if ( segmenter ) {
				return Array.from( segmenter.segment( compact ) ).length;
			}
			return Array.from( compact ).length;
		}

		function hideCounter() {
			lastRendered = '';
			$counter.attr( 'hidden', 'hidden' ).text( '' );
		}

		function renderCounter( text ) {
			var count = countText( text );
			var rendered;

			if ( count < 1 ) {
				hideCounter();
				return;
			}

			rendered = getMessage( count );
			if ( rendered !== lastRendered ) {
				$counter.text( rendered );
				lastRendered = rendered;
			}
			lastShownAt = Date.now();
			$counter.removeAttr( 'hidden' );
		}

		function updateCounter() {
			var text;

			rafId = 0;
			text = getSelectionText();

			if ( text ) {
				renderCounter( text );
				return;
			}

			if ( !selecting && Date.now() - lastShownAt > 800 ) {
				hideCounter();
			}
		}

		function scheduleUpdate() {
			if ( rafId ) {
				return;
			}
			rafId = window.requestAnimationFrame( updateCounter );
		}

		function scheduleHide() {
			window.clearTimeout( hideTimer );
			hideTimer = window.setTimeout( scheduleUpdate, 900 );
		}

		$( function () {
			$counter = $( '#mw-selection-counter' );
			if ( !$counter.length ) {
				$counter = $( '<div>' )
					.attr( {
						id: 'mw-selection-counter',
						hidden: 'hidden',
						role: 'status',
						'aria-live': 'polite',
						'aria-atomic': 'true'
					} )
					.addClass( 'mw-selection-counter' )
					.appendTo( document.body );
			}

			document.addEventListener( 'selectionchange', scheduleUpdate, { passive: true } );
			document.addEventListener( 'pointerdown', function () {
				selecting = true;
				scheduleUpdate();
			}, true );
			document.addEventListener( 'pointermove', function () {
				if ( selecting ) {
					scheduleUpdate();
				}
			}, { passive: true, capture: true } );
			document.addEventListener( 'pointerup', function () {
				selecting = false;
				scheduleUpdate();
				scheduleHide();
			}, true );
			document.addEventListener( 'keyup', function ( event ) {
				if ( event.key === 'Escape' ) {
					hideCounter();
					return;
				}
				scheduleUpdate();
			} );
			window.addEventListener( 'blur', hideCounter );
		} );
	} );
}() );