I am using a solution at: https://www.cssscript.com/rss-feed-scroller-marquee/ in order to create a tickler for my web page. All fine, but for the fact the tickler just showed the texts of the rss feed but it was impossible to click them to get to article. So I tried to tamper with it constructing a proper url and trying to animate it. Yet the item seems well constructed, but when I animate it, nothing happens. This the code of the modified js class:
/*!
* RSS Marquee
*
* Licensed under MIT
* Copyright (c) 2020 [Samuel Carreira]
*/
class RSSMarquee {
/**
*
* @param {string[]} feedURLs Feed URLs
* @param {object} elementContainer the selector of the marquee container
* @param {number} options.speed duration in ms per character. Bigger values = slow speed
* @param {number} options.maxItems specify max number of titles to show (useful to debug)
* @param {object} options.hostnameSelector The selector of the element where you want to show the URL of the news feed source (usefull for copyright atttribution)
*/
constructor(feedURLs, elementContainer, options = { speed: 110, maxItems: null, hostnameSelector: null }) {
this._feedURLs = new Array();
if (Array.isArray(feedURLs)) {
this._feedURLs = feedURLs;
} else {
this._feedURLs[0] = feedURLs;
}
const URLvalidation = this._feedURLs.every(this.validateURL);
if (!URLvalidation) {
throw new TypeError('Invalid URL on list');
}
this._urlIndex = 0;
this._anim = null;
this._newsText = '';
this._lastTime = Date.now();
if (elementContainer === null) {
throw new TypeError('Invalid element selector');
}
this._elementContainer = elementContainer;
this.styleElementContainer();
this._options = {
speed: this.validateSpeed(options.speed),
maxItems: options.maxItems,
hostnameSelector: options.hostnameSelector,
// ...options
};
this.getRSS();
}
validateSpeed(speed) {
if (!Number(speed) || speed < 50 || speed > 300) {
return 110; // default safe value
} else {
return speed;
}
}
/**
* Set the animation speed
* @param {number} speed value between 50-300
*/
set setSpeed(speed) {
this._options.speed = this.validateSpeed(speed);
}
get getSpeed() {
return this._options.speed;
}
/**
* Validate URL (uses URL interface)
*
* @param {string} url Url to check
* @returns {boolean} true if valid
*/
validateURL(url) {
try {
const u = new URL(url);
return true;
} catch (e) {
return false;
}
}
/**
* Get Hostname from url string
*
* Sample: "http://www.dnoticias.pt/rss/desporto.xml"
* returns -> www.dnoticias.pt
*
* @param {string} url url string
* @returns {string} hostname
*/
getHostname(url) {
try {
const u = new URL(url);
return u.hostname;
} catch (e) {
return '';
}
}
getRSS() {
const url = this._feedURLs[this._urlIndex];
this.fetchRSS(url)
.then((xmlText) => {
this._newsText = this.parseXMLFeed(xmlText);
this.showMarquee(this._newsText);
this.showHostname(url);
})
.catch((err) => {
console.error(err);
this.handleErrors();
});
}
handleErrors() {
const diffTime = Date.now() - this._lastTime;
if (diffTime > 5000) {
console.log('Trying next feed URL...');
this.nextURL();
this._lastTime = Date.now();
} else {
if (this._newsText === '') {
console.log('delay...');
setTimeout(() => {
this.nextURL();
}, 5000);
} else {
console.log('show again cached saved news');
this.showMarquee(this._newsText);
}
}
}
nextURL() {
this.increaseIndex();
this.getRSS();
}
styleElementContainer() {
this._elementContainer.style.overflow = 'hidden';
this._elementContainer.style.whiteSpace = 'nowrap';
}
showHostname(url) {
if (!this._options.hostnameSelector) {
return;
}
this._options.hostnameSelector.innerText = this.getHostname(url);
}
showMarquee(aCollection) {
try {
const animKeyframes = [{
transform: 'translateX(0)'
},
{
transform: 'translateX(-100%)'
}
];
const animOptions = {
duration: 25000, // The number of milliseconds each iteration of the animation takes to complete. Defaults to 0. Although this is technically optional, keep in mind that your animation will not run if this value is 0.
easing: 'linear', // The rate of the animation's change over time. Accepts the pre-defined values "linear", "ease", "ease-in", "ease-out", and "ease-in-out", or a custom "cubic-bezier" value like "cubic-bezier(0.42, 0, 0.58, 1)". Defaults to "linear".
iterations: 1, // The number of times the animation should repeat. Defaults to 1, and can also take a value of Infinity to make it repeat for as long as the element exists.
delay: 0, // The number of milliseconds to delay the start of the animation. Defaults to 0.
endDelay: 0 // The number of milliseconds to delay after the end of an animation. This is primarily of use when sequencing animations based on the end time of another animation. Defaults to 0.
};
animOptions.duration = aCollection.length * this._options.speed;
const elementChildNode = document.createElement('span');
elementChildNode.style.display = 'inline-block';
elementChildNode.style.paddingLeft = '100%';
//const textNode = document.createTextNode(text);
console.log(aCollection.lenght);
aCollection.forEach(function(item, index, array) {
elementChildNode.appendChild(item)
})
console.log("totale:");
console.log(elementChildNode);
//elementChildNode.appendChild(textNode);
//this._elementContainer.appendChild(elementChildNode);
this._anim = elementChildNode.animate(animKeyframes, animOptions);
console.log('start animation');
this._anim.onfinish = () => {
console.log('end');
while (this._elementContainer.firstChild) {
this._elementContainer.firstChild.remove();
}
delete this._anim.onfinish;
this.nextURL();
};
this._lastTime = Date.now();
} catch (err) {
console.error(err);
}
}
increaseIndex() {
this._urlIndex += 1;
if (this._urlIndex > this._feedURLs.length - 1) {
this._urlIndex = 0;
}
}
/**
* Fetch RSS
* @param {string} feedURL RSS XML url
*/
fetchRSS(feedURL) {
return new Promise((resolve, reject) => {
console.info(`Start fetching ${feedURL}...`);
fetch(feedURL, { mode: 'cors', redirect: 'follow' })
.then((response) => {
return response.text();
})
.then((xmlTxt) => {
return resolve(xmlTxt);
})
.catch(() => {
console.error('Error in fetching the RSS feed');
reject();
})
});
}
/**
* Parses RSS XML feed
*
* - Select title elementContainer
* - add dot separator between "headlines"
* - remove <![CDATA[ string
* - remove html tags
*
* @param {string} xmlText
* @returns {string} parsed feed
*/
parseXMLFeed(xmlText) {
try {
const parser = new DOMParser();
const doc = parser.parseFromString(xmlText, "text/xml");
let news = '';
let aCollection=[];
let totals = 0;
for (let item of doc.querySelectorAll('item')) {
let title = item.getElementsByTagName("title")[0].childNodes[0].nodeValue;
// let description = item.getElementsByTagName("description")[0].childNodes[0].nodeValue;
let link = item.getElementsByTagName("link")[0].childNodes[0].nodeValue;
if (title) {
if (news.length) {
news += '\xa0' + ' • ' + '\xa0';
}
title = this.remoteCData(title);
title = this.stripTags(title);
news += title;
var a = document.createElement('a');
var linkText = document.createTextNode(title);
a.appendChild(linkText);
a.title = title;
a.href = link;
aCollection.push(a);
totals += 1;
}
if (this._options.maxItems !== null && totals >= this._options.maxItems) {
console.info('Maximum items reached!');
break;
}
}
//console.log(aCollection);
//console.log(news);
console.info(`Parsed ${totals} title(s)`);
return aCollection;
} catch (err) {
console.error(err);
return ' ';
}
}
stripTags(textWithTags) {
return textWithTags.replace(/<(.|\n)*?>/g, '');
}
remoteCData(originalText) {
return originalText.replace("<![CDATA[", "").replace("]]>", "");
}
}
The non occurring animation is in function: showMarquee(aCollection). The original site shows how to test it.
Thanks,
the issue was due to commenting: this._elementContainer.appendChild(elementChildNode); moreover I had to tune speed by modifying:
animOptions.duration = aCollection.length * this._options.speed*10;
and finally to restore the dot to separate the items.