suggest: separate files for different key instead of one single json-file

[fintechdata]

Dear author,

Here is a suggest: to separate files for different key instead of one single json-file, that would improve performance in production env very well.... is pull request welcomed?

[d3x0r]

Hello, I would consider it...
the cost of opening /tracking many files might be an issue... that, and the read side would slow, because basically every key it would have to see if it's already a file...
If the modification can be wrapped in an option the can be passed like 'file-pretty' do like 'file-auto-split:true/false'