React/D3, GitHub Chart, help to switch from CSV to JSON

Hello, anyone know D3 here? I want to try this chart , but can’t figure out how to switch from CSV to JSON.

I have this model:
{ { _id: someId, createdAt: 05/31/2016, numberOfWords: 0 < number < 1000}, ..., ... }

Should I change
> d3.csv
> d3.json?

Can I pass variable and not a file with data?

Also should I change code only inside d3.csv function or there are other places which are dependent from data?