Press n or j to go to the next uncovered block, b, p or k for the previous block.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 | 1x 1x 2x 4x 5x 8x 8x 8x 8x 8x 8x 8x 8x 8x 5x 5x 5x 8x 2x 2x 8x 8x 8x 1x | var
util = require( '../util' ),
placeholderClass = 'lazy-image-placeholder';
/**
* @param {HTMLElement} root
* @return {HTMLElement[]}
*/
function queryPlaceholders( root ) {
return Array.prototype.slice.call(
root.getElementsByClassName( placeholderClass )
);
}
/**
* Load an image on demand
*
* @param {HTMLElement[]} placeholders a list of images that have not been loaded.
* @return {jQuery.Deferred}
*/
function loadImages( placeholders ) {
return util.Promise.all(
placeholders.map( ( placeholder ) => module.exports.loadImage( placeholder ).promise )
);
}
/**
* Load an image on demand
*
* @param {HTMLElement} placeholder
* @return {{promise: jQuery.Deferred<'load'|'error'>, image: HTMLImageElement}}
*/
function loadImage( placeholder ) {
var
deferred = util.Deferred(),
// data-width and height are attributes and do not specify dimension.
width = placeholder.dataset.width || '0',
height = placeholder.dataset.height || '0',
image = new Image( parseInt( width, 10 ), parseInt( height, 10 ) );
// eslint-disable-next-line mediawiki/class-doc
image.className = placeholder.dataset.class || '';
image.alt = placeholder.dataset.alt || '';
image.useMap = placeholder.dataset.usemap;
image.style.cssText = placeholder.style.cssText || '';
// When the image has loaded
image.addEventListener( 'load', () => {
// Swap the HTML inside the placeholder (to keep the layout and
// dimensions the same and not trigger layouts
image.classList.add( 'image-lazy-loaded' );
Iif ( placeholder.parentNode ) {
placeholder.parentNode.replaceChild( image, placeholder );
}
deferred.resolve( 'load' );
}, { once: true } );
image.addEventListener( 'error', () => {
// Swap the HTML and let the browser decide what to do with the broken image.
Iif ( placeholder.parentNode ) {
placeholder.parentNode.replaceChild( image, placeholder );
}
// Never reject. Quietly resolve so that Promise.all() awaits for all Deferreds to complete.
// Reevaluate using Deferred.reject in T136693.
deferred.resolve( 'error' );
}, { once: true } );
// Trigger image download after binding the load handler
image.src = placeholder.dataset.src || '';
image.srcset = placeholder.dataset.srcset || '';
return {
promise: deferred,
image
};
}
module.exports = {
placeholderClass,
queryPlaceholders,
loadImages,
loadImage,
test: {
placeholderClass
}
};
|