Floating-point strings have trailing zeroes removed.

[Shaptic]

It's debatable whether or not this is a bug, but I'd expect the input string and the output number to be the same:

echo '{ "number": "123.450" }' | jq '.number | tonumber'
123.45

Obviously, it's easy enough to work around this (using sed to remove quotes instead, or awk to print with trailing zeroes), but it requires a non-jq solution.

[pkoppstein]

@Shaptic - The problem you've noticed is just the tip of the iceberg (see e.g. https://github.com/stedolan/jq/wiki/FAQ#caveats and the currently open issues: #218 #369 #1120 #1357 #1545).

The idea of retaining and using the original representation when possible has been made, but as best I can tell, is unlikely to be incorporated into jq in the foreseeable future. More likely, perhaps, is better control of output formatting -- see #1363

In the meantime, please note that jq's string-handling capabilities can often be used to overcome jq's number-handling limitations, depending of course on the specific circumstances.

[PinkD]

I found this "feature" was fixed. Now I need to trim ending zeroes by my self.
https://github.com/jqlang/jq/wiki/FAQ#numbers