[json] formatter should keep empty lines

[donaldpipowitch]

• VSCode Version: 1.11.0-insider

Steps to Reproduce:

1. "json.format.enable": true
2. Place some new lines inside a JSON and press save. New lines are removed.

Use case:

In bigger JSON files - especially ones that allow commenting (e.g. JSON5 or .vscode/settings.json) - it is useful, if we could use new lines, but still benefit from formatting.

[francoisbeaussier]

👍

I ended up adding a bunch of empty comments here and there just to add some spacing

[OneOfOne]

Related #47361 and #37422.

[IanAshleyEckoh]

Agreed, the removing of blank lines is unhelpful. At least this could be a setting if there is support for removing the blank lines

Stumbled upon this as well, however, as I see it there are essentially two main issues here:

1. formatting removes final/trailing newline
2. formatting removes arbitrarily added empty lines within structures

Why I think these are 2 separate issues? Simply because JSON files are text files and as such, to ensure compatibility and portability, adding a final newline actually makes is a text file in the first place (a line needs to end with a newline, otherwise it's not really a line of text, just some data).

Now, there are a lot of discussions with pros and cons about this but that is not the issue. What the actual issue is is that if I originally created the JSON file with a trailing newline, I obviously want to have it there - for whatever reason. If my original file did not have one, I may not want it. This is an extremely simple case to handle and would solve almost all issue that got closed as duplicates of this issue.

Now, the second issue (which is the actual issue here) is much more complex to handle, since it involves the parsing context to recognize and handle it, which is completely different from just recognizing a trailing newline state and retain it (or have configuration to add/remove it).

[progonkpa]

Not ending a file with a new line is a quite big fail imo because,
"Many older tools misbehave if the last line of data in a text file is not terminated with a newline or carriage return / new line."