Jack

Jack is a JSON pretty-printer written in Janet.

Installation

Install Janet per instructions.

Install dependencies using jpm deps.

Build an executable binary by running jpm build. You can place this in your path, e.g. /usr/local/bin. Alternatively, if your $JANET_PATH is set right (should be the default) you can run jpm install to install the binary into your Janet bin directory.

Usage

Jack reads from stdin and outputs to stdout.

Example:

λ jack < test.json
{
  "rolodex": {},
  "address": {
    "state": "NY",
    "streetAddress": "212nd Street",
    "city": "New York",
    "postalCode": "10021-3100"
  },
  "children": [],
  "lastName": "Smith",
  "age": 27,
  "firstName": "John",
  "phoneNumbers": [
    {
      "number": "212555-1234",
      "type": "home"
    },
    {
      "number": "646555-4567",
      "type": "office"
    }
  ],
  "spouse": null,
  "isAlive": true
}

If you just run jack without any stdin, you will be prompted to enter valid JSON text. You can end your input with Ctrl-D. Press it 2x at the beginning of a line (you may press enter to get to the new line) or 3x in the middle of a line to end input.

Usage from within vim

This is really what it's made for: prettify JSON you copied into vim.

Let's make use of vim's excellent shelling out feature. Visually select a block of JSON and then execute:

!jack

This will replace your selection with the prettified version.