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: 10234	/local1/tlutelli/issta_data/temp/all_js/javascript/2007_temp/2007/10234/1da2447043e17fc11a2a1986efb527260cbcad89/nsLoginManager.js/clean/toolkit/components/passwordmgr/src/nsLoginManager.js