repo_description: Promise based HTTP client for the browser and node.js
repo_topics: hacktoberfest http-client javascript nodejs promise
code: 'use strict';
  
  /**
   * Determines whether the specified URL is absolute
   *
   * @param {string} url The URL to test
   *
   * @returns {boolean} True if the specified URL is absolute, otherwise false
   */
  export default function isAbsoluteURL(url) {
    // A URL is considered absolute if it begins with "<scheme>://" or "//" (protocol-relative URL).
    // RFC 3986 defines scheme name as a sequence of characters beginning with a letter and followed
    // by any combination of letters, digits, plus, period, or hyphen.
    if (typeof url !== 'string') {
      return false;
    }
  
    return /^([a-z][a-z\d+\-.]*:)?\/\//i.test(url);
  }
  