[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

[ghost]

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."

[broofa]

'Worth noting that this is particularly frustrating when working with JSONC documents (JSON + comments). For example:

{
  // REFERENCE: https://www.npmjs.com/package/markdown-it
  "html": true, // Enable HTML tags in source

  // This is only for full CommonMark compatibility.
  "breaks": true, // Convert '\n' in paragraphs into <br>

  // Double + single quotes replacement pairs, when typographer enabled,
  // and smartquotes on. Could be either a String or an Array.
  "quotes": "“”‘’"
}

Turns into this when saved:

{
  // REFERENCE: https://www.npmjs.com/package/markdown-it
  "html": true, // Enable HTML tags in source
  // This is only for full CommonMark compatibility.
  "breaks": true, // Convert '\n' in paragraphs into <br>
  // Double + single quotes replacement pairs, when typographer enabled,
  // and smartquotes on. Could be either a String or an Array.
  "quotes": "“”‘’"
}

[bmitc]

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."

I found this issue due to all the warnings GitHub places for files without newlines at the end of files. I saw that the JSON formatter is removing the end of file newline. This should probably even be a separate setting, because I think I should be able to format a JSON, including removing whitespace or newlines or something, while still keeping the end of file newline to maintain compliance with tools that expect that, whatever they may be.

[aeschli]

@bmitc The JSON formatter observes the files.insertFinalNewline setting

[bmitc]

@aeschli Thank you for the heads up on that setting!

[aeschli]

Implemented by microsoft/node-jsonc-parser#66