rem: var usernames = logins.map(function (l) l.username); 
add: var found = logins.some(function(l) { foundLogin = l; return (l.username == username); }); 
context:                 var usernames = logins.map(function (l) l.username);
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2007_temp/2007/9421/1370011fe124b98b5ba251bdaedb21896d72ef9c/nsLoginManager.js/clean/toolkit/components/passwordmgr/src/nsLoginManager.js