jf

jf is a jo alternative, A small utility to safely format and print JSON objects in the commandline.

However, unlike jo, where you build the JSON object by nesting jo outputs, jf works similar to printf, i.e. it expects the template in YAML format as the first argument, and then the values for the placeholders as subsequent arguments.

Install

Cargo

As a CLI tool

cargo install jf

Or as a library:

cargo add jf

Nixpkgs

nix-env -f https://github.com/NixOS/nixpkgs/tarball/nixos-unstable -iA jf

Or download binary from the latest release.

Usage

jf TEMPLATE [VALUE]... [NAME=VALUE]...

Where TEMPLATE may contain the following placeholders:

• %q, %(NAME)q, %(NAME=DEFAULT)q for quoted and safely escaped JSON string.
• %s, %(NAME)s, %(NAME=DEFAULT)s for JSON values other than string.

And [VALUE]... [NAME=VALUE]... are the values for the placeholders.

• Use %s or %q syntax to declare positional placeholders.
• Use %(NAME)s or %(NAME)q syntax to declare named placeholders.
• Use %(NAME=DEFAULT)s or %(NAME=DEFAULT)q syntax to declare default values for named placeholders.
• Use %% to escape a literal % character.
• Pass values for positional placeholders in the same order as in the template.
• Pass values for named placeholders using NAME=VALUE syntax.
• Do not declare or pass positional placeholders or values after named ones.
• To get the jf version number, run jf %v.

Example:

jf "hello: %q" world
# jo hello=world
# {"hello":"world"}

jf "hello: {beautiful: %(what)q}" what=world
# jo hello=$(jo beautiful=world)
# {"hello":{"beautiful":"world"}}

jf "d: {m: %s, n: %s}" 10 20
# jo d[m]=10 d[n]=20
# {"d":{"m":10,"n":20}}

jf "{a: {b: %s, c: {d: %s, f: %s}, d: {e: [%s, %q]}}, b: {e: [%q]}}" 0 1 true 2 sam hi
# jo -d\|first_char_only a\|b=0 a\|c\|d=1 a\|d\|e[]=2 a\|d\|e[]=sam a\|c[f]@1 b\|e[]=hi
# {"a":{"b":0,"c":{"d":1,"f":true},"d":{"e":[2,"sam"]}},"b":{"e":["hi"]}}

Rust Library

let json = match jf::format(["%q", "JSON Formatted"].map(Into::into)) {
    Ok(value) => value,
    Err(jf::Error::Usage) => {
        bail!("usage: mytool: TEMPLATE [VALUE]... [NAME=VALUE]...")
    }
    Err(jf::Error::Jf(e)) => bail!("mytool: {e}"),
    Err(jf::Error::Json(e)) => bail!("mytool: json: {e}"),
    Err(jf::Error::Yaml(e)) => bail!("mytool: yaml: {e}"),
};

Packaging