Question

I’m trying to extract a URL from an array using JS but my code doesn’t seem to be returning anything.

Would appreciate any help!

var pages = [
    "www.facebook.com|Facebook",
    "www.twitter.com|Twitter",
    "www.google.co.uk|Google"
    ];

function url1_m1(pages, pattern) {
    var URL = '' // variable ready to accept URL
    for (var i = 0; i < pages[i].length; i++) {
        // for each character in the chosen page
        if (pages[i].substr(i, 4) == "www.") {
            // check to see if a URL is there
            while (pages[i].substr(i, 1) != "|") {
                // if so then lets assemble the URL up to the colon
                URL = URL + pages[i].substr(i, 1);
                i++;
            }
        }
    }
    return (URL);
    // let the user know the result
}
alert(url1_m1(pages, "twitter")); // should return www.twitter.com

Answer 1

In your case you can use this:

var page = "www.facebook.com|Facebook";
alert(page.match(/^[^|]+/)[0]);

You can see this here

---

It’s just example of usage RegExp above. Full your code is:

var pages = [
  "www.facebook.com|Facebook",
  "www.twitter.com|Twitter",
  "www.google.co.uk|Google"
];

var parseUrl = function(url){
  return url.match(/^(www\.[^|]+)+/)[0];
};

var getUrl = function(param){
  param = param.toLowerCase();
  var page = _(pages).detect(function(page){ 
    return page.toLowerCase().search(param)+1 !== 0; 
  });
  return parseUrl(page);
};

alert(getUrl('twitter'));

You can test it here

In my code I have used Underscore library. You can replace it by standard for or while loops for find some array item.
And of course improve my code by some validations – for example, for undefined value, or if values in array are incorrect or something else.

Good luck!