JSFiddle - React, Tailwind, and code Playground

JavaScript

/**
 * Extend the Array object
 * @param candid The string to search for
 * @returns Returns the index of the first match or -1 if not found
*/
Array.prototype.searchFor = function(needle) {
    for (var i=0; i<this.length; i++)
        if (this[i].indexOf(needle) == 0)
            return i;
    return -1;
};



    someWebsites = ['somesite.com/subdir','someotherwebsite.com']
    function checkTabURL(url) {
        switch (someWebsites.searchFor(url)) {
            case 0:
                console.log('case 0');
                break;
            case 1:
                console.log('case 1');
                break;
            default:
                console.log('default');
                break;
        }
        
    } 

    checkTabURL('somesite.com');