[BUG] npm converts tabs to spaces if used in package.json

[Newbytee]

What / Why

If one uses tabs to indent their package.json file, npm will overwrite these tabs with spaces. It does not warn you that you used tabs instead of spaces, and the documentation for package.json does not mention how it should be indented.

When

• When an npm command is issued that mutates package.json (for example, installing a package).

Where

• n/a

How

Current Behavior

• npm will replace tabs with spaces as it mutates package.json.

Steps to Reproduce

• Write a skeleton package.json using tabs for indentation
• Install a package
• Observe that the tabs have been replaced by spaces (1 space for each tab)

Expected Behavior

• npm sees that package.json is indented with tabs and continues to indent with tabs.

Who

• n/a

References

• n/a

[ljharb]

What version of npm are you using? In my experience this long-standing bug was fixed in npm 6.

[Newbytee]

Hmm, seems I can't reproduce it now. Maybe I forgot some space somewhere.

For the record, I'm using npm 6.14.4.