jfmt is my JSON formatter. There's a few things this does different than most JSON formatters I could find, which in my opinion makes the output much nicer.
Install with go install zgo.at/jfmt/cmd/jfmt@latest.
Or import zgo.at/jfmt to use in Go code.
It tries to be a little smarter about what should be on a single line. Things like this:
{
"nums": [
12,
4,
901,
12,
742,
],
"strings": [
"k",
"p",
"bas",
"pqz",
"q21",
],
"obj" {
"k": "v"
}
}
Are just silly, and splitting it out over many lines like that isn't helpful. So that becomes:
{
"nums": [12, 4, 901, 12, 742],
"strings": ["k", "p", "bas", "pqz", "q21"],
"obj" {"k": "v"}
}
It will still write to multiple lines if it's too long.
It will also align the keys; which I rather like.
Like many JSON formatting tools keys are sorted alphabetically, but it puts values that fit on a single line first, to avoid avoid things like this:
{
"additional": false,
"definitions": {
[.. very long object ..]
}
"title": "JSON schema for Python project metadata and configuration",
"type": "object",
}
I don't like these kind of "dangling primitives", so that that becomes:
{
"additional": false,
"title": "JSON schema for Python project metadata and configuration",
"type": "object",
"definitions": {
[.. very long object ..]
}
}
And things like this:
{
"arr5": [
[
[
[
[
{"type": "string", "value": "#"}
]
]
]
]
]
}
Can just be written on a single line, too:
{
"arr5": [[[[[{"type": "string", "value": "#"}]]]]],
}
There's a bunch of cases like this; in general it tries to be as concise as possible as long as it doesn't sacrifice readability.
The downside of this is that it's a bit slower and uses more memory. It's still plenty fast enough for almost all use cases; the largest file in schemastore.org (kubernetes-definitions.json, 17,500 lines/950K) takes about 120ms on my laptop (vs. 30ms with Go's default MarshalIndent). I spent almost zero effort optimising anything, so there's probably a lot to win here.