Validate Spotify Playlist HTTP and URI

script.js

/*
 * Script to validate Spotify playlist HTTP and URI's
 * Valid format: http://open.spotify.com/user/__username__/playlist/__playlistID__
 *               spotify:user:__username__:playlist:__playlistID__
 *
 * License: MIT
 */
 
function validateSpotifyPlaylistHTTPandURI(input) {
    isValid = false;        

    /*
     * VALIDATE SPOTIFY HTTP
     ***********************
     */
    if(input.indexOf('/')>-1) {
        // not a valid spotify URI - check if valid Spotify HTTP and convert

        parts = input.split('/');
        spotifyIndex = -1;

        for(b=0;b<parts.length;b++) {
            // check if the URL is to spotify
            if(parts[b].indexOf('spotify.com') >- 1) {
             spotifyIndex = b;
             break;
            }
        }

        if(spotifyIndex > -1) {
            if(parts.length > spotifyIndex + 4) {
                // the input is long enough to hold the additional parameters
                isValid = true;

                // make sure the structure of the url is correct
                // it is not possible to validate the username or playlist ID
                if( parts[spotifyIndex + 1] != 'user') isValid = false;
                if( parts[spotifyIndex + 3] != 'playlist') isValid = false;
            }            
        }
    }    
    
    /*
     * VALIDATE SPOTIFY URI
     **********************
     */        
    if(!isValid && input.indexOf(':')>-1) {

        parts = input.split(':');
        spotifyIndex = -1;

        for(b=0;b<parts.length;b++) {
            // check if the URL is to spotify
            if(parts[b].indexOf('spotify') >- 1) {
             spotifyIndex = b;
             break;
            }
        }

        if(spotifyIndex > -1) {
            if(parts.length > spotifyIndex + 4) {
                // the input is long enough to hold the additional parameters
                isValid = true;

                // make sure the structure of the url is correct
                // it is not possible to validate the username or playlist ID
                if( parts[spotifyIndex + 1] != 'user') isValid = false;
                if( parts[spotifyIndex + 3] != 'playlist') isValid = false;
            }            
        }
    }
    return isValid;        
}

https://open.spotify.com/playlist/37i9dQZF1DXcBWIGoYBM5M?si=cd98478d007c4ac9
it's a valid Spotify playlist but your script says it's not.