Pretty-print your JSON in Ruby with more power than is provided by JSON.pretty_generate. In particular, like Ruby's pp (pretty print), NeatJSON will keep objects on one line if they fit, but break them over multiple lines if needed.

Here's an excerpt (from a much larger JSON):

{
  "navigation.createroute.poi":[
    {"text":"Lay in a course to the Hilton","params":{"poi":"Hilton"}},
    {"text":"Take me to the airport","params":{"poi":"airport"}},
    {"text":"Let's go to IHOP","params":{"poi":"IHOP"}},
    {"text":"Show me how to get to The Med","params":{"poi":"The Med"}},
    {"text":"Create a route to Arby's","params":{"poi":"Arby's"}},
    {
      "text":"Go to the Hilton by the Airport",
      "params":{"poi":"Hilton","location":"Airport"}
    },
    {
      "text":"Take me to the Fry's in Fresno",
      "params":{"poi":"Fry's","location":"Fresno"}
    }
  ],
  "navigation.eta":[
    {"text":"When will we get there?"},
    {"text":"When will I arrive?"},
    {"text":"What time will I get to the destination?"},
    {"text":"What time will I reach the destination?"},
    {"text":"What time will it be when I arrive?"}
  ]
}

gem install neatjson

require 'neatjson'

o = { b:42.005, a:[42,17], longer:true, str:"yes
please" }

puts JSON.neat_generate(o)
#=> {"b":42.005,"a":[42,17],"longer":true,"str":"yes\nplease"}

puts JSON.neat_generate(o,sort:true)
#=> {"a":[42,17],"b":42.005,"longer":true,"str":"yes\nplease"}

puts JSON.neat_generate(o,sort:true,padding:1,after_comma:1)
#=> { "a":[ 42, 17 ], "b":42.005, "longer":true, "str":"yes\nplease" }

puts JSON.neat_generate(o,sort:true,wrap:40)
#=> {
#=>   "a":[42,17],
#=>   "b":42.005,
#=>   "longer":true,
#=>   "str":"yes\nplease"
#=> }

puts JSON.neat_generate(o,sort:true,wrap:40,decimals:2)
#=> {
#=>   "a":[42,17],
#=>   "b":42.01,
#=>   "longer":true,
#=>   "str":"yes\nplease"
#=> }

puts JSON.neat_generate(o,sort:->(k){ k.length },wrap:40,aligned:true)
#=> {
#=>   "a"     :[42,17],
#=>   "b"     :42.005,
#=>   "str"   :"yes\nplease",
#=>   "longer":true
#=> }

puts JSON.neat_generate(o,sort:true,wrap:40,aligned:true,around_colon:1)
#=> {
#=>   "a"      : [42,17],
#=>   "b"      : 42.005,
#=>   "longer" : true,
#=>   "str"    : "yes\nplease"
#=> }

puts JSON.neat_generate(o,sort:true,wrap:40,aligned:true,around_colon:1,short:true)
#=> {"a"      : [42,17],
#=>  "b"      : 42.005,
#=>  "longer" : true,
#=>  "str"    : "yes\nplease"}

a = [1,2,[3,4,[5]]]
puts JSON.neat_generate(a)
#=> [1,2,[3,4,[5]]]

puts JSON.pretty_generate(a) # oof!
#=> [
#=>   1,
#=>   2,
#=>   [
#=>     3,
#=>     4,
#=>     [
#=>       5
#=>     ]
#=>   ]
#=> ]

puts JSON.neat_generate( a, wrap:true, short:true )
#=> [1,
#=>  2,
#=>  [3,
#=>   4,
#=>   [5]]]

You may pass any of the following option symbols to neat_generate:

• :wrap — The maximum line width before wrapping. Use false to never wrap, or true (or -1) to always wrap. Default: 80
• :indent — Whitespace used to indent each level when wrapping. Default: " " (two spaces)
• :indent_last — Indent the closing bracket/brace for arrays and objects? Default: false
• :short — Keep the output 'short' when wrapping? This puts opening brackets on the same line as the first value, and closing brackets on the same line as the last. Default: false
  • This causes the :indent and :indent_last options to be ignored, instead basing indentation on array and object padding.
• :sort — Sort the keys for objects to be in alphabetical order (true), or supply a lambda for customized sort order. Default: false
• :aligned — When wrapping objects, line up the colons (per object)? Default: false
• :decimals — Decimal precision to use for non-integer numbers; use false to keep float values precise. Default: false
• :array_padding — Number of spaces to put inside brackets for arrays. Default: 0
• :object_padding — Number of spaces to put inside braces for objects. Default: 0
• :padding — Shorthand to set both :array_padding and :object_padding. Default: 0
• :before_comma — Number of spaces to put before commas (for both arrays and objects). Default: 0
• :after_comma — Number of spaces to put after commas (for both arrays and objects). Default: 0
• :around_comma — Shorthand to set both :before_comma and :after_comma. Default: 0
• :before_colon_1 — Number of spaces before a colon when the object is on one line. Default: 0
• :after_colon_1 — Number of spaces after a colon when the object is on one line. Default: 0
• :before_colon_n — Number of spaces before a colon when the object is on multiple lines. Default: 0
• :after_colon_n — Number of spaces after a colon when the object is on multiple lines. Default: 0
• :before_colon — Shorthand to set both :before_colon_1 and :before_colon_n. Default: 0
• :after_colon — Shorthand to set both :after_colon_1 and :after_colon_n. Default: 0
• :around_colon — Shorthand to set both :before_colon and :after_colon. Default: 0

If you supply a lambda to the sort option, it will be passed three values:

• The string name of the object key.
• The associated value.
• The object being sorted.

For example:

# Ruby sorting examples
obj = {e:3, a:2, c:3, b:2, d:1, f:3}

JSON.neat_generate obj, sort:true                              # sort by key name
#=> {"a":2,"b":2,"c":3,"d":1,"e":3,"f":3}

JSON.neat_generate obj, sort:->(k){ k }                        # sort by key name (long way)
#=> {"a":2,"b":2,"c":3,"d":1,"e":3,"f":3}

JSON.neat_generate obj, sort:->(k,v){ [-v,k] }                 # sort by descending value, ascending key
#=> {"c":3,"e":3,"f":3,"a":2,"b":2,"d":1}

JSON.neat_generate obj, sort:->(k,v,h){ h.values.count(v) }    # sort by count of keys with same value
#=> {"d":1,"a":2,"b":2,"e":3,"c":3,"f":3}

// JavaScript sorting examples
var obj = {e:3, a:2, c:3, b:2, d:1, f:3};

neatJSON( obj, {sort:true} );                                              // sort by key name
// {"a":2,"b":2,"c":3,"d":1,"e":3,"f":3}

neatJSON( obj, { sort:function(k){ return k }} );                          // sort by key name (long way)
// {"a":2,"b":2,"c":3,"d":1,"e":3,"f":3}

neatJSON( obj, { sort:function(k,v){ return -v }} );                       // sort by descending value
// {"e":3,"c":3,"f":3,"a":2,"b":2,"d":1}

var countByValue = {};
for (var k in obj) countByValue[obj[k]] = (countByValue[obj[k]]||0) + 1;
neatJSON( obj, { sort:function(k,v,h){ return countByValue[v] } } );       // sort by count of same value
// {"d":1,"a":2,"b":2,"e":3,"c":3,"f":3}

Note that the JavaScript version of NeatJSON does not provide a mechanism for cascading sort in the same manner as Ruby.

NeatJSON is copyright ©2015–2016 by Gavin Kistner and is released under the MIT License. See the LICENSE.txt file for more details.

For bugs or feature requests please open issues on GitHub. For other communication you can email the author directly.

• Figure out the best way to play with custom objects that use to_json for their representation.
• Detect circular references.
• Possibly allow illegal JSON values like NaN or Infinity.
• Possibly allow "JSON5" output (legal identifiers unquoted, etc.)

• v0.8.1 - April 22nd, 2016

  • Make NeatJSON work with Opal (by removing all in-place string mutations)

• v0.8 - April 21st, 2016

  • Allow sort to take a lambda for customized sorting of object key/values.

• v0.7.2 - April 14th, 2016

  • Fix JavaScript library to support objects without an Object constructor (e.g. location).
  • Online HTML converter accepts arbitrary JavaScript values as input in addition to JSON.

• v0.7.1 - April 6th, 2016

  • Fix Ruby library to work around bug in Opal.

• v0.7 - March 26th, 2016

  • Add indentLast/indent_last feature.

• v0.6.2 - February 8th, 2016

  • Use memoization to avoid performance stalls when wrapping deeply-nested objects/arrays.
    Thanks @chroche

• v0.6.1 - October 12th, 2015

  • Fix handling of nested empty objects and arrays. (Would cause a runtime error in many cases.)
    • This change causes empty arrays in a tight wrapping scenario to appear on a single line where they would previously take up three lines.

• v0.6 - April 26th, 2015

  • Added before_colon_1 and before_colon_n to distinguish between single-line and multi-line objects.

• v0.5 - April 19th, 2015

  • Do not format integers (or floats that equal their integer) using decimals option.
  • Make neatJSON() JavaScript available to Node.js as well as web browsers.
  • Add (Node-based) testing for the JavaScript version.

• v0.4 - April 18th, 2015

  • Add JavaScript version with online runner.

• v0.3.2 - April 16th, 2015

  • Force YARD to use Markdown for documentation.

• v0.3.1 - April 16th, 2015

  • Remove some debugging code accidentally left in.

• v0.3 - April 16th, 2015

  • Fix another bug with short:true and wrapping array values inside objects.

• v0.2 - April 16th, 2015

  • Fix bug with short:true and wrapping values inside objects.

• v0.1 - April 15th, 2015

  • Initial release.