Update solution.js

[pdwarkanath]

Using reduce rather than a loop

[ccarruitero]

Hi @pdwarkanath

Thanks for your PR.

Your changes are not passing the linter, because the semicolon.

Personally, I think the for loop could be more easy to understand for a beginner developer.

Maybe this could be added as an alternative solution in test folder. What do you think?

[pdwarkanath]

@ccarruitero Sure. Should I just add this as alternate_01.js file to the test folder?

[ccarruitero]

@pdwarkanath following the pattern used for other files there, the file should be named valid_02.js

Make sure run npm test in your local machine to ensure linter and tests are passing.