Fx – Terminal JSON Viewer




it is written in Go. What does it have to do with npx/npm at all? Did I miss something about these tools?


Where do you see npm/npx mentioned?


The project supports JS scripts as arguments to process the data:


It's hard to tell from the docs if there is any JS involved if you just pipe JSON data to fx. I would hope not, since it mentions being written in Go for performance.


This is what I was wondering as well. Is there an interpreter built into the go binary? or is it using my node install under the hood?

Edit: Answered my own question. I installed it into a podman container with nothing else in it, and it printed this when trying to execute js:

    Node.js or Deno is required to run fx with reducers.

strace (on Linux) would have told you that without needing to user podman


at https://fx.wtf/getting-started it says:

$ cat file.json | npx fx .field


It seems it would work since they release an npm package too: https://www.npmjs.com/package/fx

A bit surprising, I wonder if they implemented it in JS too, or somehow managed to distribute their Go program on npm.

Edit: They indeed have a separate non-interactive version in JS: https://github.com/antonmedv/fx/tree/master/npm


Looks great!

What is the website https://fx.wtf/ built-in?




It is nice for PCs, but requiring Node.js limits its use on servers.


Pretty cool! I actually wrote something VERY similar a couple of years ago: sless[1]. It's a tool for viewing json-based structured logs. Just like your tool, you can explore into a json object. The difference is, it expects the input to have many json objects, newline separated, and it shows few keys as a preview of the object, to make looking for something in the log easier. It's not quite complete but basic browsing works. It was mainly written to learn more about Urwid[2], a library similar to Curses.

1: https://github.com/dpedu2/sless

2: https://urwid.org/


Hey HN friends!

I've taken `fx` back to the drawing board and completely rewritten it from the ground up. Excited to share what's new:

1. *Going Big*: `fx` now gracefully handles even the most massive JSON files.

2. *A New TUI Look*: Dive deep into your data with a revamped terminal interface—now with themes!

3. *Swift Navigation with Dig Fuzzy Search*: Feeling lost in JSON? Just type `.` and navigate with ease.

4. *Powerful Regex Search*: Scan across your entire JSON content with precision.

5. *Elegant Long String Wraps*: No more cut-offs. Your strings wrap beautifully now.

6. *All Things JSON*: Added love for comments, trailing commas, and JSON streams.

Pouring my heart and soul into this rewrite has been a journey to make `fx` faster and more powerful. If you find value in what I've crafted and want to support its future, consider sponsoring on GitHub.

Would love to hear your thoughts and feedback!


wow nice, I'll give this a try.

I've always used jq for viewing json, but it's the wrong tool for my use. I basically want to explore json interactively, not parse it specifically. So the workflow is to keep "jq"ing it, and modifying my jq query until I find what I'm looking for.

Your tool looks like it allows interactive exploration.


You may be interested in an interactive jq tool like jiq or others: https://github.com/fiatjaf/awesome-jq (do a ctrl-f for "interactive" on this page).


That page doesn't include jless[1], which seems very similar to fx and will give you a jq selector for whatever node you're on

1: https://jless.io/


This thread is a gem after gem, thank you!


What can you do with the JSON in the TUI? Anything besides looking at it? (https://fx.wtf/getting-started#json-processing but from the TUI?)

Built something similar, but with love for all things CUE (also works for JSON/Yaml) (https://youtu.be/XNBqBWO4y08)

Yours looks to have a better object navigation, I might have to be inspired by it!

How do you like Bubbletea? We went with tcell/tview (fork) for more control of the UI & event handling



Is there a commonly-used grammar for "json with comments and trailing commas" or does everyone just try to copy the jsonc from vscode?


It's basically https://json5.org/

CUE will happily take your JSON with comments and extra commas, or no commas too (lists still need them), most keys can be unquoted, and it's just a one-liner to get valid json or yaml from it


Jsonnet does too I believe. I wanted to like Cue but it only works with Go and it doesn't actually let you link the schemas you write from the "document" files, which means no automatic schema checking and no IDE support. Giving up two huge benefits of having a schema in the first place.


Some feedback:

- Some indication of how far down you've scrolled would be useful for "situational awareness". Perhaps a percentage number in the status bar (like emacs/vim?)

- I miss not having the Home/End keys bound to the goto top/bottom actions

- The cursor behavior when pressing PageDn/PageUp throws me off.

Emacs when pressing PageDn: Cursor ends up at the top of the window.

Vim: Cursor stays at the current position.

notepad.exe: Cursor ends up in the middle of the window.

Fx: Cursor ends up at the bottom of the window.

- The . navigation is very neat with the tab completion. Probably stupid observation: If you remove the alphabet key shortcuts you wouldn't need the (non-discoverable) dot. :)


how do you use the Built-in Functions? i tried them but it gives me error every time


I am probably missing something but is interactive mode not a flag? Is it just what happens with a longer JSON automatically?


The other day, I found myself in need of visualising a tree of paths, like this:

I ended up converting it to a JSON with a one-off Python script, and then using fx for the viewing. It worked very well! Thank you for the tool!

(Incidentally, I’ve been writing my own viewer [0] to satisfy my original need more straightforwardly, but that’s still in very early stages.)

[0]: https://github.com/nathell/treeviewer


As in filesystem paths? Are you aware of `tree`?



Not necessarily filesystem paths (in my case, the paths correspond to RocksDB keys). And I’d like to be able to fold/unfold subtrees, search within node names, and call arbitrary commands for a given path in the tree, from within a TUI. So no, `tree` won’t cut it.


amazing! Does someone know something like this for yaml? (does not have to be cli)


Very cool. Not a huuge deal, but for open source software, I don't totally appreciate the http call to a bitly tracker in the install script...


Just use:

    go install github.com/antonmedv/fx@latest

> Built using the Go programming language for efficient performance.

Do you mean to say "efficiency" or "performance"? I dont see both working like that


It's correct as it is. Performance can be good or bad. "...for efficiency" would be correct, but if they were to write only "...for performance" it would missing a qualifier.


Having used https://jqlang.github.io/jq/, wondering your pitch on advantages, alternative use cases for using fx?

[deleted by user]

jq is probably better if you don't have node or deno installed since fx can't do expressions without it


Not OP but

      echo '{"name": "world"}' | fx 'x => x.name' 'x => `Hello, ${x}!`'
Is immediately grokkable compared to jq's syntax.

I love jq, I think it's extremely powerful, but I have to load up the documentation in a side window every time I have use it.


Equivalent jq seems okay here:

    echo '{"name": "world"}' | jq '"Hello \(.name)"'

Yes and both can be expressed in js and jq. Poinjt is what JS is known by much more peopel. As fx uses Node or Deno we for example can use lodash in fx:

    fx '_.groupBy("commit.author.name")' '_.mapValues(size)'
       '_.toPairs' '_.sortBy(1)' '_.reverse' '_.take(10)' '_.fromPairs'
To do if in jq, it will take me much more time and extensive documentation reading.

What’s the original JSON? Happy to try and express this in jq


Looks like the GitHub API: https://docs.github.com/en/free-pro-team@latest/rest/commits...

I'm looking forward to your jq version. I love jq and use it all the time, but for anything of that complexity, I'd probably just use Python.


jq seems shorter but I don't see how it's more intuitive - ".name" is pretty basic jq syntax but how do I know \() is syntax for wrapping selectors within strings? I've used jq for many years and tbh I've never done string templating with it, so I would need to go digging in the docs.

You can argue that's the case for any language, but it's the fundamental reason DSLs rarely capture the mainstream for on-the-fly utilities. Leveraging existing knowledge of a more heavily used syntax really helps here. Look at awk for example - it's been around forever, and despite its power and ubiquity in OS installs, you'll still see sed in many many more bash scripts because it's leaning on widely used familiar syntax rather than a DSL.

That said - the fx example has "x => Hello, ${x}!" where I would expect "x => `Hello, ${x}!`", so that does indicate to me that fx has its own gotchas lurking - this example could just be contrived to look intuitive.


Maybe the person you replied to fixed a syntax error in an edit? The backticks are required, and are currently in their comment.


jq is YADSL though vs JS which is ubiquitous. Same reason most people can't use awk or sed.


As someone who doesn't use jq, a number of questions immediately jump out at me. Why is the input string double qouted ('"input"')? What does the backslash annotate? At first it looks like an escape similar to regex, but the other bracket doesn't have it so it must mean something else? Etc. Of course I could look the answers up, but the point is I can't tell without looking it up. While the code is short it feels similar to Awk, if you know it it's trivial, if you don't know it it's hard to be sure what it does without trying it out.


Happy jq user as well.

But is jq interactive?


ijq [1] is. I am using it almost every time I need to come up with a jq expression. However, it gets noticeably laggy with enormous JSONs.

[1]: https://sr.ht/~gpanders/ijq/


I know JavaScript, so I immediately know a lot of the `fx` syntax.

I always found the `jqc


I know JavaScript, so I immediately know a lot of the `fx` syntax.

I always found the `jq` syntax required many round-trips to the mail and more trial and error to get the syntax right.


Would've been awesome if results are displayed under the commands. For example, command

  echo '{"name": "hello"}\n{"name": "world"}' | fx '.name'
would output what? My guess is hello world but it might be hello\nworld.

FYI: .wtf top domain is blocked in HaGeZi's The World's Most Abused TLDs: https://raw.githubusercontent.com/hagezi/dns-blocklists/main...

Might wanna change to something else.


This is ridiculous. I will not change my domain because of someone’s blocklist.


could've used this a few years ago before jq became so second nature, cool


> In fx, arguments are treated as JavaScript functions. Input data is passed sequentially through each provided function.

> echo '{"name": "world"}' | fx 'x => x.name' 'x => `Hello, ${x}!`'

Wow, that is so nice. Having to memorize JQ syntax is such a pain.


This could be done with nushell.



Is the output ascii diagram only? Seems like a pretty different use case


No the output is a table object, you can apply other operations to it like sort, etc. the shell displays them in this ascii art way at the end but you can also write to files in various formats.


sure can do, if you already use that shell [1], but personally I like specific tools for specific jobs such as jq [2], fx, csvq [3] etc, there's value in decoupling shells from utils (modularity, speed, innovation etc).

[1] I don't but tempted to try, like its data-types concept

[2] https://jqlang.github.io/jq/

[3] https://github.com/mithrandie/csvq


Any comparison to jless?


fx looks to work from the command line (without viewing) to do more than just inspect, looks like you can do pretty much anything to it with a bit of JS, though not from the TUI afaict

There are many JSON viewers, I would think that inspecting with collapsable sections ought to be right in VS Code with LSP/treesitter, no extra tools needed.

What's more interesting to me is what can you do with the JSON in these tools, validate, filter, transform, chain...?


Need to have a bit more of a play with it but I really like it so far. I mainly see myself using it to pipe into (like from curl or the gh cli).

One thing that isn't clear to me is how to actually use the themes you can display with fx --themes.


Will update the docs. But it is easy:

    FX_THEME=2 fx data.json

This looks really nice.


I find `gron` to be very helpful for generating jq query strings