vanilla-lazyload/src/lazyload.reveal.js

A fast, lightweight script to load images as they enter the viewport. SEO friendly, it supports responsive images (both srcset + sizes and picture) and progressive JPEG

import { setSources } from "./lazyload.setSources";
import { getWasProcessedData, setWasProcessedData } from "./lazyload.data";
import { addOneShotEventListeners } from "./lazyload.event";
import { addClass } from "./lazyload.class";
import { callbackIfSet } from "./lazyload.callback";

const managedTags = ["IMG", "IFRAME", "VIDEO"];

export function revealElement(element, instance, force) {
	var settings = instance._settings;
	if (!force && getWasProcessedData(element)) {
		return; // element has already been processed and force wasn't true
	}
	callbackIfSet(settings.callback_enter, element);
	if (managedTags.indexOf(element.tagName) > -1) {
		addOneShotEventListeners(element, instance);
		addClass(element, settings.class_loading);
	}
	setSources(element, instance);
	setWasProcessedData(element);
	callbackIfSet(settings.callback_set, element);
}