How to trim all spaces except those within quotes for large JSON file

Question

I am currently working on a large JSON file, and wish to shorten it by deleting all extra spaces, tabs, returns, etc. that are not within quotes. The file is some 100,000 lines of code and hard for my other scripts to use it quickly. The file originally looks like:

{
  "path": "/math/", 
  "id": "math", 
  "title": "Math Title",       
  "icon_url": "/images/power-mode/badges/circles-40x40.png",   
  "contains": [
    "Topic", 
    "Video", 
   "Exercise"
  ], 
  "children": [], 
  "parent_id": "root",
  "ancestor_ids": [
    "root"
  ], 
  "description": "null", 
  "kind": "Topic", 
  "h_position": -10,
  "v_position": 6, 
  "slug": "math"
}

and I wish for it to look like this after deleting unnecessary spaces, tabs,returns, etc:

{"path":"/math/","id":"math","title":"Math Title","icon_url":"/images/power-mode/badges/circles-40x40.png",     
"contains":["Topic","Video","Exercise"],"children":[],"parent_id":"root","ancestor_ids":["root"],   
"description": "null","kind":"Topic","h_position":-10,"v_position":6,"slug":"math"}

Basically every space should be deleted except for those within quotes.

Answer 1

You can use jq's -c or --compact-output option:

jq -c '' < your-file.json

Demo:

$ echo '
> {
>   "a": "b"
> }' | jq -c ''
{"a":"b"}

Answer 2

You could read the json into code and then output it to file specifying a compact format, your spaces within quotes will be preserved in the strings.

In python you could use the native json libraries

import json
json.loads(your filestream)
json.dumps(your output stream) // the native output of json.dumps is compact

Details in the python docs https://docs.python.org/2/library/json.html

But you should be able to do the same technique in any language that handles json.