Need to make this non repeating random feed

JavaScript
1

Here is the code I have to select a random news feed. What I want is to modify this to pick a random feed, but if the feed picked is the current feed to pick again.

<script>
var feeds = [
'http%3A%2F%2Ffeeds.skynews.com%2Ffeeds%2Frss%2Fus.xml',
'http%3A%2F%2Ffeeds.bbci.co.uk%2Fnews%2Fworld%2Frss.xml',
'https%3A%2F%2Fwww.nytimes.com%2Fsvc%2Fcollections%2Fv1%2Fpublish%2Fhttps%3A%2F%2Fwww.nytimes.com%2Fsection%2Fus%2Frss.xml',
'https%3A%2F%2Fwww.yahoo.com%2Fnews%2Frss',
'http%3A%2F%2Ffeeds.reuters.com%2FReuters%2FdomesticNews',
'http%3A%2F%2Ffeeds.washingtonpost.com%2Frss%2Frss_blogpost'
];

function randomFeed(feeds) {
   return feeds[Math.floor(Math.random() * feeds.length)];

}

var feed = randomFeed(feeds);

var link = "<script language='JavaScript' src='http://feedroll.com/rssviewer/feed2js.php?src=" + feed + "&chan=title&num=4&desc=1&targ=y&utf=y&html=y' charset='UTF-8' type='text/javascript'><\/script>";

</script>
2

I’m sure it could be done more succinctly, but maybe this?

const randomFeed = (function(){
    let prevIndex = null

    return function randomfeed(feeds){
        const newIndex = Math.floor(Math.random() * feeds.length)
        if (newIndex === prevIndex) return randomfeed(feeds)
        prevIndex = newIndex
        return feeds[newIndex] 
    }
}())

for (let i = 0; i < 100; i++) {
  console.log(randomFeed(feeds))  
}
1 Like
3

You could do it with a recursive call but you’ll need to pass the current feed to the call

(excuse the code since it’s been a while since I’ve done JS)

function randomFeed(feeds, currentFeed) {
   var newFeed = feeds[Math.floor(Math.random() * feeds.length)];
   return (currentFeed == newFeed ? randomFeed(feeds, currentFeed) : newFeed);
}

Or (thinking cap on…), you could filter out the current feed first which would take out the recursion and ensure only one call.

function randomFeed(feeds, currentFeed) {
   var filteredFeeds = feeds.filter(feed => feed != currentFeed);
   return filteredFeeds[Math.floor(Math.random() * filteredFeeds.length)];
}

words.filter(word => word != thisWord);
1 Like
4

How would I pass the current feed to the call?

5

I was going based off this. You must know it’s the current feed somehow since you’re asking how to not return it…

6

The only way I know what the current feed is, is what is showing on the page. How would I store that info in a javascript variable or some kind of marker that I can look at the next time the news is refreshed to see if the random pick is the same feed as what is currently displayed?

7

Starting with the flawed logic path.

<script>
var feeds = [
'http%3A%2F%2Ffeeds.skynews.com%2Ffeeds%2Frss%2Fus.xml',
'http%3A%2F%2Ffeeds.bbci.co.uk%2Fnews%2Fworld%2Frss.xml',
'https%3A%2F%2Fwww.nytimes.com%2Fsvc%2Fcollections%2Fv1%2Fpublish%2Fhttps%3A%2F%2Fwww.nytimes.com%2Fsection%2Fus%2Frss.xml',
'https%3A%2F%2Fwww.yahoo.com%2Fnews%2Frss',
'http%3A%2F%2Ffeeds.reuters.com%2FReuters%2FdomesticNews',
'http%3A%2F%2Ffeeds.washingtonpost.com%2Frss%2Frss_blogpost'
];

function randomFeed() {
   while((ret = Math.floor(Math.random() * feeds.length)) == feed) {}
   return ret;
}

var feed = randomFeed(feeds);

var link = "<script language='JavaScript' src='http://feedroll.com/rssviewer/feed2js.php?src=" + feeds[feed] + "&chan=title&num=4&desc=1&targ=y&utf=y&html=y' charset='UTF-8' type='text/javascript'><\/script>";

</script>

(You will probably need to instantiate feed before calling it, though)

1 Like
8

After some more research using Google, here is what I came up with. It seems to work.

<script>

var feeds = [
'http%3A%2F%2Ffeeds.skynews.com%2Ffeeds%2Frss%2Fus.xml',
'http%3A%2F%2Ffeeds.bbci.co.uk%2Fnews%2Fworld%2Frss.xml',
'https%3A%2F%2Fwww.nytimes.com%2Fsvc%2Fcollections%2Fv1%2Fpublish%2Fhttps%3A%2F%2Fwww.nytimes.com%2Fsection%2Fus%2Frss.xml',
'https%3A%2F%2Fwww.yahoo.com%2Fnews%2Frss',
'http%3A%2F%2Ffeeds.reuters.com%2FReuters%2FdomesticNews',
'http%3A%2F%2Ffeeds.washingtonpost.com%2Frss%2Frss_blogpost'
];

function randomFeed(feeds) {
   return feeds[Math.floor(Math.random() * feeds.length)];

}

var vOneLS = localStorage.getItem("vOneLocalStorage");

var feed = randomFeed(feeds);
var currentFeed = feed;

if (vOneLS == currentFeed) {
var feed = randomFeed(feeds);
}

localStorage.setItem("vOneLocalStorage", currentFeed);

var link = "<script language='JavaScript' src='http://feedroll.com/rssviewer/feed2js.php?src=" + feed + "&chan=title&num=4&desc=1&targ=y&utf=y&html=y' charset='UTF-8' type='text/javascript'><\/script>";

</script>
9

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