How to avoid VsCode Prettier to break chain functions in new lines.?

Note that in Prettier v2.0.4 this issue is fixed. Now, as long as your line of code is within the length specified in your config or the default 80, it will be left in one line. Otherwise, it will be wrapped to multiple lines.

I had to upgrade my prettier in order for these changes to be put into affect.

$ yarn upgrade -g prettier --latest

[EDIT] In Prettier v2.0.4 this issue is fixed. Update to latest version

This is an issue in prettier. The PR's to add this feature has not yet been merged from what i understand.

Currently to get what you want, what i can suggest is to ignore the next node in the abstract syntax tree from formatting using the // prettier-ignore comments.

// prettier-ignore  
let m = moment().startOf("day").subtract(30, "days");   

There are variations of these ignore statements, like one could ignore within a ranger or one could even ignore a particular file too. Do check out the official prettier documentations to know more of it's implementation.