diff options
Diffstat (limited to 'wp-includes/js/wp-emoji-loader.js')
| -rw-r--r-- | wp-includes/js/wp-emoji-loader.js | 424 |
1 files changed, 424 insertions, 0 deletions
diff --git a/wp-includes/js/wp-emoji-loader.js b/wp-includes/js/wp-emoji-loader.js new file mode 100644 index 0000000..3d2a161 --- /dev/null +++ b/wp-includes/js/wp-emoji-loader.js @@ -0,0 +1,424 @@ +/** + * @output wp-includes/js/wp-emoji-loader.js + */ + +/** + * Emoji Settings as exported in PHP via _print_emoji_detection_script(). + * @typedef WPEmojiSettings + * @type {object} + * @property {?object} source + * @property {?string} source.concatemoji + * @property {?string} source.twemoji + * @property {?string} source.wpemoji + * @property {?boolean} DOMReady + * @property {?Function} readyCallback + */ + +/** + * Support tests. + * @typedef SupportTests + * @type {object} + * @property {?boolean} flag + * @property {?boolean} emoji + */ + +/** + * IIFE to detect emoji support and load Twemoji if needed. + * + * @param {Window} window + * @param {Document} document + * @param {WPEmojiSettings} settings + */ +( function wpEmojiLoader( window, document, settings ) { + if ( typeof Promise === 'undefined' ) { + return; + } + + var sessionStorageKey = 'wpEmojiSettingsSupports'; + var tests = [ 'flag', 'emoji' ]; + + /** + * Checks whether the browser supports offloading to a Worker. + * + * @since 6.3.0 + * + * @private + * + * @returns {boolean} + */ + function supportsWorkerOffloading() { + return ( + typeof Worker !== 'undefined' && + typeof OffscreenCanvas !== 'undefined' && + typeof URL !== 'undefined' && + URL.createObjectURL && + typeof Blob !== 'undefined' + ); + } + + /** + * @typedef SessionSupportTests + * @type {object} + * @property {number} timestamp + * @property {SupportTests} supportTests + */ + + /** + * Get support tests from session. + * + * @since 6.3.0 + * + * @private + * + * @returns {?SupportTests} Support tests, or null if not set or older than 1 week. + */ + function getSessionSupportTests() { + try { + /** @type {SessionSupportTests} */ + var item = JSON.parse( + sessionStorage.getItem( sessionStorageKey ) + ); + if ( + typeof item === 'object' && + typeof item.timestamp === 'number' && + new Date().valueOf() < item.timestamp + 604800 && // Note: Number is a week in seconds. + typeof item.supportTests === 'object' + ) { + return item.supportTests; + } + } catch ( e ) {} + return null; + } + + /** + * Persist the supports in session storage. + * + * @since 6.3.0 + * + * @private + * + * @param {SupportTests} supportTests Support tests. + */ + function setSessionSupportTests( supportTests ) { + try { + /** @type {SessionSupportTests} */ + var item = { + supportTests: supportTests, + timestamp: new Date().valueOf() + }; + + sessionStorage.setItem( + sessionStorageKey, + JSON.stringify( item ) + ); + } catch ( e ) {} + } + + /** + * Checks if two sets of Emoji characters render the same visually. + * + * This function may be serialized to run in a Worker. Therefore, it cannot refer to variables from the containing + * scope. Everything must be passed by parameters. + * + * @since 4.9.0 + * + * @private + * + * @param {CanvasRenderingContext2D} context 2D Context. + * @param {string} set1 Set of Emoji to test. + * @param {string} set2 Set of Emoji to test. + * + * @return {boolean} True if the two sets render the same. + */ + function emojiSetsRenderIdentically( context, set1, set2 ) { + // Cleanup from previous test. + context.clearRect( 0, 0, context.canvas.width, context.canvas.height ); + context.fillText( set1, 0, 0 ); + var rendered1 = new Uint32Array( + context.getImageData( + 0, + 0, + context.canvas.width, + context.canvas.height + ).data + ); + + // Cleanup from previous test. + context.clearRect( 0, 0, context.canvas.width, context.canvas.height ); + context.fillText( set2, 0, 0 ); + var rendered2 = new Uint32Array( + context.getImageData( + 0, + 0, + context.canvas.width, + context.canvas.height + ).data + ); + + return rendered1.every( function ( rendered2Data, index ) { + return rendered2Data === rendered2[ index ]; + } ); + } + + /** + * Determines if the browser properly renders Emoji that Twemoji can supplement. + * + * This function may be serialized to run in a Worker. Therefore, it cannot refer to variables from the containing + * scope. Everything must be passed by parameters. + * + * @since 4.2.0 + * + * @private + * + * @param {CanvasRenderingContext2D} context 2D Context. + * @param {string} type Whether to test for support of "flag" or "emoji". + * @param {Function} emojiSetsRenderIdentically Reference to emojiSetsRenderIdentically function, needed due to minification. + * + * @return {boolean} True if the browser can render emoji, false if it cannot. + */ + function browserSupportsEmoji( context, type, emojiSetsRenderIdentically ) { + var isIdentical; + + switch ( type ) { + case 'flag': + /* + * Test for Transgender flag compatibility. Added in Unicode 13. + * + * To test for support, we try to render it, and compare the rendering to how it would look if + * the browser doesn't render it correctly (white flag emoji + transgender symbol). + */ + isIdentical = emojiSetsRenderIdentically( + context, + '\uD83C\uDFF3\uFE0F\u200D\u26A7\uFE0F', // as a zero-width joiner sequence + '\uD83C\uDFF3\uFE0F\u200B\u26A7\uFE0F' // separated by a zero-width space + ); + + if ( isIdentical ) { + return false; + } + + /* + * Test for UN flag compatibility. This is the least supported of the letter locale flags, + * so gives us an easy test for full support. + * + * To test for support, we try to render it, and compare the rendering to how it would look if + * the browser doesn't render it correctly ([U] + [N]). + */ + isIdentical = emojiSetsRenderIdentically( + context, + '\uD83C\uDDFA\uD83C\uDDF3', // as the sequence of two code points + '\uD83C\uDDFA\u200B\uD83C\uDDF3' // as the two code points separated by a zero-width space + ); + + if ( isIdentical ) { + return false; + } + + /* + * Test for English flag compatibility. England is a country in the United Kingdom, it + * does not have a two letter locale code but rather a five letter sub-division code. + * + * To test for support, we try to render it, and compare the rendering to how it would look if + * the browser doesn't render it correctly (black flag emoji + [G] + [B] + [E] + [N] + [G]). + */ + isIdentical = emojiSetsRenderIdentically( + context, + // as the flag sequence + '\uD83C\uDFF4\uDB40\uDC67\uDB40\uDC62\uDB40\uDC65\uDB40\uDC6E\uDB40\uDC67\uDB40\uDC7F', + // with each code point separated by a zero-width space + '\uD83C\uDFF4\u200B\uDB40\uDC67\u200B\uDB40\uDC62\u200B\uDB40\uDC65\u200B\uDB40\uDC6E\u200B\uDB40\uDC67\u200B\uDB40\uDC7F' + ); + + return ! isIdentical; + case 'emoji': + /* + * Why can't we be friends? Everyone can now shake hands in emoji, regardless of skin tone! + * + * To test for Emoji 14.0 support, try to render a new emoji: Handshake: Light Skin Tone, Dark Skin Tone. + * + * The Handshake: Light Skin Tone, Dark Skin Tone emoji is a ZWJ sequence combining 🫱 Rightwards Hand, + * 🏻 Light Skin Tone, a Zero Width Joiner, 🫲 Leftwards Hand, and 🏿 Dark Skin Tone. + * + * 0x1FAF1 == Rightwards Hand + * 0x1F3FB == Light Skin Tone + * 0x200D == Zero-Width Joiner (ZWJ) that links the code points for the new emoji or + * 0x200B == Zero-Width Space (ZWS) that is rendered for clients not supporting the new emoji. + * 0x1FAF2 == Leftwards Hand + * 0x1F3FF == Dark Skin Tone. + * + * When updating this test for future Emoji releases, ensure that individual emoji that make up the + * sequence come from older emoji standards. + */ + isIdentical = emojiSetsRenderIdentically( + context, + '\uD83E\uDEF1\uD83C\uDFFB\u200D\uD83E\uDEF2\uD83C\uDFFF', // as the zero-width joiner sequence + '\uD83E\uDEF1\uD83C\uDFFB\u200B\uD83E\uDEF2\uD83C\uDFFF' // separated by a zero-width space + ); + + return ! isIdentical; + } + + return false; + } + + /** + * Checks emoji support tests. + * + * This function may be serialized to run in a Worker. Therefore, it cannot refer to variables from the containing + * scope. Everything must be passed by parameters. + * + * @since 6.3.0 + * + * @private + * + * @param {string[]} tests Tests. + * @param {Function} browserSupportsEmoji Reference to browserSupportsEmoji function, needed due to minification. + * @param {Function} emojiSetsRenderIdentically Reference to emojiSetsRenderIdentically function, needed due to minification. + * + * @return {SupportTests} Support tests. + */ + function testEmojiSupports( tests, browserSupportsEmoji, emojiSetsRenderIdentically ) { + var canvas; + if ( + typeof WorkerGlobalScope !== 'undefined' && + self instanceof WorkerGlobalScope + ) { + canvas = new OffscreenCanvas( 300, 150 ); // Dimensions are default for HTMLCanvasElement. + } else { + canvas = document.createElement( 'canvas' ); + } + + var context = canvas.getContext( '2d', { willReadFrequently: true } ); + + /* + * Chrome on OS X added native emoji rendering in M41. Unfortunately, + * it doesn't work when the font is bolder than 500 weight. So, we + * check for bold rendering support to avoid invisible emoji in Chrome. + */ + context.textBaseline = 'top'; + context.font = '600 32px Arial'; + + var supports = {}; + tests.forEach( function ( test ) { + supports[ test ] = browserSupportsEmoji( context, test, emojiSetsRenderIdentically ); + } ); + return supports; + } + + /** + * Adds a script to the head of the document. + * + * @ignore + * + * @since 4.2.0 + * + * @param {string} src The url where the script is located. + * + * @return {void} + */ + function addScript( src ) { + var script = document.createElement( 'script' ); + script.src = src; + script.defer = true; + document.head.appendChild( script ); + } + + settings.supports = { + everything: true, + everythingExceptFlag: true + }; + + // Create a promise for DOMContentLoaded since the worker logic may finish after the event has fired. + var domReadyPromise = new Promise( function ( resolve ) { + document.addEventListener( 'DOMContentLoaded', resolve, { + once: true + } ); + } ); + + // Obtain the emoji support from the browser, asynchronously when possible. + new Promise( function ( resolve ) { + var supportTests = getSessionSupportTests(); + if ( supportTests ) { + resolve( supportTests ); + return; + } + + if ( supportsWorkerOffloading() ) { + try { + // Note that the functions are being passed as arguments due to minification. + var workerScript = + 'postMessage(' + + testEmojiSupports.toString() + + '(' + + [ + JSON.stringify( tests ), + browserSupportsEmoji.toString(), + emojiSetsRenderIdentically.toString() + ].join( ',' ) + + '));'; + var blob = new Blob( [ workerScript ], { + type: 'text/javascript' + } ); + var worker = new Worker( URL.createObjectURL( blob ), { name: 'wpTestEmojiSupports' } ); + worker.onmessage = function ( event ) { + supportTests = event.data; + setSessionSupportTests( supportTests ); + worker.terminate(); + resolve( supportTests ); + }; + return; + } catch ( e ) {} + } + + supportTests = testEmojiSupports( tests, browserSupportsEmoji, emojiSetsRenderIdentically ); + setSessionSupportTests( supportTests ); + resolve( supportTests ); + } ) + // Once the browser emoji support has been obtained from the session, finalize the settings. + .then( function ( supportTests ) { + /* + * Tests the browser support for flag emojis and other emojis, and adjusts the + * support settings accordingly. + */ + for ( var test in supportTests ) { + settings.supports[ test ] = supportTests[ test ]; + + settings.supports.everything = + settings.supports.everything && settings.supports[ test ]; + + if ( 'flag' !== test ) { + settings.supports.everythingExceptFlag = + settings.supports.everythingExceptFlag && + settings.supports[ test ]; + } + } + + settings.supports.everythingExceptFlag = + settings.supports.everythingExceptFlag && + ! settings.supports.flag; + + // Sets DOMReady to false and assigns a ready function to settings. + settings.DOMReady = false; + settings.readyCallback = function () { + settings.DOMReady = true; + }; + } ) + .then( function () { + return domReadyPromise; + } ) + .then( function () { + // When the browser can not render everything we need to load a polyfill. + if ( ! settings.supports.everything ) { + settings.readyCallback(); + + var src = settings.source || {}; + + if ( src.concatemoji ) { + addScript( src.concatemoji ); + } else if ( src.wpemoji && src.twemoji ) { + addScript( src.twemoji ); + addScript( src.wpemoji ); + } + } + } ); +} )( window, document, window._wpemojiSettings ); |