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Editing: wp-emoji-loader.js
/** * @output wp-includes/js/wp-emoji-loader.js */ /* eslint-env es6 */ // Note: This is loaded as a script module, so there is no need for an IIFE to prevent pollution of the global scope. /** * 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 */ const settings = /** @type {WPEmojiSettings} */ ( JSON.parse( document.getElementById( 'wp-emoji-settings' ).textContent ) ); // For compatibility with other scripts that read from this global, in particular wp-includes/js/wp-emoji.js (source file: js/_enqueues/wp/emoji.js). window._wpemojiSettings = settings; /** * Support tests. * @typedef SupportTests * @type {object} * @property {?boolean} flag * @property {?boolean} emoji */ const sessionStorageKey = 'wpEmojiSettingsSupports'; const 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} */ const 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} */ const 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 is used to determine if the browser is rendering an emoji with multiple data points * correctly. set1 is the emoji in the correct form, using a zero-width joiner. set2 is the emoji * in the incorrect form, using a zero-width space. If the two sets render the same, then the browser * does not support the emoji correctly. * * 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 ); const 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 ); const rendered2 = new Uint32Array( context.getImageData( 0, 0, context.canvas.width, context.canvas.height ).data ); return rendered1.every( ( rendered2Data, index ) => { return rendered2Data === rendered2[ index ]; } ); } /** * Checks if the center point of a single emoji is empty. * * This is used to determine if the browser is rendering an emoji with a single data point * correctly. The center point of an incorrectly rendered emoji will be empty. A correctly * rendered emoji will have a non-zero value at the center point. * * 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 6.8.2 * * @private * * @param {CanvasRenderingContext2D} context 2D Context. * @param {string} emoji Emoji to test. * * @return {boolean} True if the center point is empty. */ function emojiRendersEmptyCenterPoint( context, emoji ) { // Cleanup from previous test. context.clearRect( 0, 0, context.canvas.width, context.canvas.height ); context.fillText( emoji, 0, 0 ); // Test if the center point (16, 16) is empty (0,0,0,0). const centerPoint = context.getImageData(16, 16, 1, 1); for ( let i = 0; i < centerPoint.data.length; i++ ) { if ( centerPoint.data[ i ] !== 0 ) { // Stop checking the moment it's known not to be empty. return false; } } return true; } /** * 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. * @param {Function} emojiRendersEmptyCenterPoint Reference to emojiRendersEmptyCenterPoint function, needed due to minification. * * @return {boolean} True if the browser can render emoji, false if it cannot. */ function browserSupportsEmoji( context, type, emojiSetsRenderIdentically, emojiRendersEmptyCenterPoint ) { let 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 Sark 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 ([C] + [Q]). */ isIdentical = emojiSetsRenderIdentically( context, '\uD83C\uDDE8\uD83C\uDDF6', // as the sequence of two code points '\uD83C\uDDE8\u200B\uD83C\uDDF6' // 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': /* * Is there a large, hairy, humanoid mythical creature living in the browser? * * To test for Emoji 17.0 support, try to render a new emoji: Hairy Creature. * * The hairy creature emoji is a single code point emoji. Testing for browser * support required testing the center point of the emoji to see if it is empty. * * 0xD83E 0x1FAC8 (\uD83E\u1FAC8) == 馃珗 Hairy creature. * * When updating this test, please ensure that the emoji is either a single code point * or switch to using the emojiSetsRenderIdentically function and testing with a zero-width * joiner vs a zero-width space. */ const notSupported = emojiRendersEmptyCenterPoint( context, '\uD83E\u1FAC8' ); return ! notSupported; } 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. * @param {Function} emojiRendersEmptyCenterPoint Reference to emojiRendersEmptyCenterPoint function, needed due to minification. * * @return {SupportTests} Support tests. */ function testEmojiSupports( tests, browserSupportsEmoji, emojiSetsRenderIdentically, emojiRendersEmptyCenterPoint ) { let canvas; if ( typeof WorkerGlobalScope !== 'undefined' && self instanceof WorkerGlobalScope ) { canvas = new OffscreenCanvas( 300, 150 ); // Dimensions are default for HTMLCanvasElement. } else { canvas = document.createElement( 'canvas' ); } const 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'; const supports = {}; tests.forEach( ( test ) => { supports[ test ] = browserSupportsEmoji( context, test, emojiSetsRenderIdentically, emojiRendersEmptyCenterPoint ); } ); 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 ) { const script = document.createElement( 'script' ); script.src = src; script.defer = true; document.head.appendChild( script ); } settings.supports = { everything: true, everythingExceptFlag: true }; // Obtain the emoji support from the browser, asynchronously when possible. new Promise( ( resolve ) => { let supportTests = getSessionSupportTests(); if ( supportTests ) { resolve( supportTests ); return; } if ( supportsWorkerOffloading() ) { try { // Note that the functions are being passed as arguments due to minification. const workerScript = 'postMessage(' + testEmojiSupports.toString() + '(' + [ JSON.stringify( tests ), browserSupportsEmoji.toString(), emojiSetsRenderIdentically.toString(), emojiRendersEmptyCenterPoint.toString() ].join( ',' ) + '));'; const blob = new Blob( [ workerScript ], { type: 'text/javascript' } ); const worker = new Worker( URL.createObjectURL( blob ), { name: 'wpTestEmojiSupports' } ); worker.onmessage = ( event ) => { supportTests = event.data; setSessionSupportTests( supportTests ); worker.terminate(); resolve( supportTests ); }; return; } catch ( e ) {} } supportTests = testEmojiSupports( tests, browserSupportsEmoji, emojiSetsRenderIdentically, emojiRendersEmptyCenterPoint ); setSessionSupportTests( supportTests ); resolve( supportTests ); } ) // Once the browser emoji support has been obtained from the session, finalize the settings. .then( ( supportTests ) => { /* * Tests the browser support for flag emojis and other emojis, and adjusts the * support settings accordingly. */ for ( const 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; // When the browser can not render everything we need to load a polyfill. if ( ! settings.supports.everything ) { const src = settings.source || {}; if ( src.concatemoji ) { addScript( src.concatemoji ); } else if ( src.wpemoji && src.twemoji ) { addScript( src.twemoji ); addScript( src.wpemoji ); } } } );
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