Nice good solution!

Hi, mattcree !
'bitshift left' is a good solution!
I'll keep it in my notes.

Thanks a lot.

can you please tell me how it will take only bcacb.as according to my code it will take character from end so "abcacba" it will take "a" from end and index wil be start from 0 and it is found at ""0"" index because index is search from 0th index. therefore substring will become "abcacba"....

You might want to add Test.assertEquals(longestPalindrome("abcacba"), 7) as a test case. I've seen a solution which effectively iterates the array, for each character looks up the next index of of that character and decides if it's a palindrome -- this case will fail that method because it will only consider bcacb as a palindrome, since a -> a would only get the first half of the palindrome in the string.

27 guys passed the Elixir kata. It's not a problem of the kata but a CW problem. './runners/elixir' is the CW program which runs Elixir.
My own solution has now the same problem...:-(
Report it as a bug at : https://www.codewars.com/topics/bug-reports.

module.js:457
throw err;
^

Error: Cannot find module './runners/elixir'
at Function.Module._resolveFilename (module.js:455:15)
at Function.Module._load (module.js:403:25)
at Module.require (module.js:483:17)
at require (internal/module.js:20:19)
at Object.module.exports.run (/runner/lib/runner.js:3:10)
at Object. (/runner/run-json.js:1:87)
at Module._compile (module.js:556:32)
at Object.Module._extensions..js (module.js:565:10)
at Module.load (module.js:473:32)
at tryModuleLoad (module.js:432:12)

This happens every time I want to submit or test my Elixir solution.