1'use strict'; 2module.exports = function (url) { 3 if (typeof url !== 'string') { 4 throw new TypeError('Expected a string, got ' + typeof url); 5 } 6 7 url = url.trim(); 8 9 if (/^\.*\/|^(?!localhost)\w+:/.test(url)) { 10 return url; 11 } 12 13 return url.replace(/^(?!(?:\w+:)?\/\/)/, 'http://'); 14}; 15