29

Is it possible to stringify a JSON object to look like this, with arrays in one line - not indented

{
    "Repeat": {
        "Name": [["Top_level","All"],[[1,1]]],
        "Link": [["Top_level"],[[1,1]]]
    },
    "Delete": ["Confirm","Cancel"],
    "Move": ["Up","Down"],
    "Number": ["Ascending","Descending"]
}
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10 Answers 10

Reset to default
23

Try this:

var obj = {"Repeat": {"Name":[["Top_level","All"],[[1,1]]],"Link": [["Top_level"],[[1,1]]]},"Delete": ["Confirm","Cancel"],"Move": ["Up","Down"],"Number": ["Ascending","Descending"]};

JSON.stringify(obj,function(k,v){
   if(v instanceof Array)
      return JSON.stringify(v);
   return v;
},2);

Result:

"{
  "Repeat": {
    "Name": "[[\"Top_level\",\"All\"],[[1,1]]]",
    "Link": "[[\"Top_level\"],[[1,1]]]"
  },
  "Delete": "[\"Confirm\",\"Cancel\"]",
  "Move": "[\"Up\",\"Down\"]",
  "Number": "[\"Ascending\",\"Descending\"]"
}"
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7 Comments

Thanks that looks more like it should be. I will try it out in good time. What does k do?
k and v are the key/values for object that gets passed in to that function, in this case k doesn't do anything
The arrays come out as single strings; is there an equally smart way to return them to arrays? If so your answer definitely gets the tick
It prints out like this:` "images": "[\"2\",\"3\",\"4\",\"5\",\"6\",\"7\"]"`
This part gets a little tricky, what I did when I implemented it was to strip out the quotes and backslashes with regex. As for the arrays you can make a recursive method that loops through every time an array is detected and tack it on the end of output string. It can get a little messy from here.
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18

Taking the answers from ericbowden and bigp, I produced the below function which allows me to pretty print JSON while keeping an array on a single line and keeping the array in array form instead of converting it to a string.

function prettyPrintArray(json) {
  if (typeof json === 'string') {
    json = JSON.parse(json);
  }
  output = JSON.stringify(json, function(k,v) {
    if(v instanceof Array)
      return JSON.stringify(v);
    return v;
  }, 2).replace(/\\/g, '')
        .replace(/\"\[/g, '[')
        .replace(/\]\"/g,']')
        .replace(/\"\{/g, '{')
        .replace(/\}\"/g,'}');

  return output;
}
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2 Comments

Thanks for your answer - this works great. Here I have adapted your function to pass JSLint: const prettyPrintArray = obj => JSON.stringify( obj, (key, val) => (val instanceof Array) ? JSON.stringify(val) : val, 2).replace(/\\/g, '').replace(/\[/g, '[').replace(/\]/g,']').replace(/\{/g, '{').replace(/\}/g,'}');
If you have a string value that ends with a square or curly bracket this will not produce a valid JSON string as the replace calls at the bottom, will replace the string's closing quotation mark.
13

If you mean to display short arrays as single lines, consider using json-stringify-pretty-compact. It produces results looking as follows:

{
  "bool": true,
  "short array": [1, 2, 3],
  "long array": [
    {"x": 1, "y": 2},
    {"x": 2, "y": 1},
    {"x": 1, "y": 1},
    {"x": 2, "y": 2}
  ]
}
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1 Comment

This works pretty well once you get it going. It's an odd process though - or maybe I don't know what I'm doing... It installs easily with npm. After that, to get it working, your script tag needs to point to 'index.js' (There isn't a json-stringify-pretty-compact js file). Then you have to comment out the last line, like this: //module.exports = stringify. Then you can use it in place of JSON.stringify, like this: stringify(jSONObject, null, 2). Indeed it does make JSON look much better.
9

Another approach which I took:

obj => JSON.stringify(obj, (k,v) => Array.isArray(v) ? JSON.stringify(v) : v, 2)
.replace(/"\[[^"\]]*]"/g, r => JSON.stringify(JSON.parse(r)).substr(1).slice(0,-1))

*Array must not contain strings (notice the " in the not contains inside the regex), if you remove it it will catch key,values of: "[": "[1,2,3,4]",

Update 2020-03 - I worked out a more stable solution

const obj = {
  "first_name": "John",
  "last_name": "Smith",
  "age": 21,
  "hobbies": [ "programming", "workout", null, undefined, 24, "\"has double quotes\"" ],
  "nested": {
    "arr": [ "one", "two", "three" ],
  },
  "nested_arr": [
    "first as string",
    {
      "latin": [ "alpha", "beta", "[gamma]" ]
    },
    null
  ]
};

const stringify = (obj, indent = 2) => 
  JSON.stringify(obj, (key, value) => {
    if (Array.isArray(value) && !value.some(x => x && typeof x === 'object')) {
      return `\uE000${JSON.stringify(value.map(v => typeof v === 'string' ? v.replace(/"/g, '\uE001') : v))}\uE000`;
    }
    return value;
  }, indent).replace(/"\uE000([^\uE000]+)\uE000"/g, match => match.slice(2, -2).replace(/\\"/g, '"').replace(/\uE001/g, '\\\"'));

console.log(stringify(obj));

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3 Comments

Do you think it would get this result: www.glasier.hk - select JSON
For general purpose prettying I would suggest using a third party library as suggested by @Piotr Migdal
The substr method has since been deprecated. Instead one can use match.substring(2, match.length - 2).
8

Another modern answer for an old question: Take a look at FracturedJson. That link will take you to the web version, but it's available as a commandline app, and libraries for .NET and JS.

FracturedJson will inline arrays/objects as long as they're neither too long nor too complex. It can likewise split arrays into multiple lines with multiple items per line.

Here's an example using the default settings, but you can adjust them to whatever works best for your data.

{
    "SimpleItem": 77,
    "ComplexObject": {
        "Subthing1": {"X": 55, "Y": 19, "Z": -4},
        "Subthing2": { "Q": null, "W": [-2, -1, 0, 1] },
        "Distraction": [[], null, null]
    },
    "ShortArray": ["blue", "blue", "orange", "gray"],
    "LongArray": [
        2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 
        79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 
        163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 
        251, 257, 263, 269, 271, 277, 281, 283, 293
    ],
    "LongArray2": [
        [19, 2],
        [3, 8],
        [14, 0],
        [9, 9],
        [9, 9],
        [0, 3],
        [10, 1],
        [9, 1],
        [9, 2],
        [6, 13],
        [18, 5],
        [4, 11],
        [12, 2]
    ]
}

Disclosure: I'm the author of FracturedJson. It's open source under an MIT license.

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Comments

4

Try this:

JSON.stringify(obj,function(k,v){
   if(v instanceof Array)
      return JSON.stringify(v);
   return v;
},4)
.replace(/"\[/g, '[')
.replace(/\]"/g, ']')
.replace(/\\"/g, '"')
.replace(/""/g, '"');
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1 Comment

I tried but this does not work with multi level objects
2

Mind you this uses lodash to detect Arrays and Objects, here's another method that will keep the "leaf" objects compact on one line:

_.jsonPretty = function(obj, indent) {
    if(!indent) indent = 2;

    return JSON.stringify(obj, function(k,v) {
        //Check if this is a leaf-object with no child Arrays or Objects:
        for(var p in v) {
            if(_.isArray(v[p]) || _.isObject(v[p])) {
                return v;
            }
        }

        return JSON.stringify(v);

        //Cleanup the escaped strings mess the above generated:
    }, indent).replace(/\\/g, '')
        .replace(/\"\[/g, '[')
        .replace(/\]\"/g,']')
        .replace(/\"\{/g, '{')
        .replace(/\}\"/g,'}');
};

And just use it like this:

_.jsonPretty(yourObjectToStringify);

Here's an example before...

{
  "type": "light-item",
  "name": "Waiting",
  "ringSeqLooping": true,
  "ringSeqHoldLast": false,
  "ringSteps": [
    {
      "type": "light-step",
      "time": 1,
      "audioClipName": "Off",
      "audioVolume": 1,
      "lights": [
        {
          "state": "FadeOn",
          "color": "#fff"
        },
        {
          "state": "Off",
          "color": "#fff"
        },
        {
          "state": "Off",
          "color": "#fff"
        },
        {
          "state": "Off",
          "color": "#fff"
        },
        {
          "state": "Off",
          "color": "#fff"
        },
        {
          "state": "Off",
          "color": "#fff"
        },
        {
          "state": "Off",
          "color": "#fff"
        },
        {
          "state": "Off",
          "color": "#fff"
        }
      ]
    },
    {
      "type": "light-step",
      "time": "0.5",
      "audioClipName": "Off",
      "audioVolume": 1,
      "lights": [
        {
          "state": "FadeOff",
          "color": "#fff"
        },
        {
          "state": "Off",
          "color": "#fff"
        },
        {
          "state": "Off",
          "color": "#fff"
        },
        {
          "state": "Off",
          "color": "#fff"
        },
        {
          "state": "Off",
          "color": "#fff"
        },
        {
          "state": "Off",
          "color": "#fff"
        },
        {
          "state": "Off",
          "color": "#fff"
        },
        {
          "state": "Off",
          "color": "#fff"
        }
      ]
    }
  ],
  "stripSeqLooping": true,
  "stripSeqHoldLast": false,
  "stripSteps": [
    {
      "type": "light-step",
      "time": "2",
      "audioClipName": "Off",
      "audioVolume": 1,
      "lights": [
        {
          "state": "Off",
          "color": "#fff"
        },
        {
          "state": "Off",
          "color": "#fff"
        },
        {
          "state": "Off",
          "color": "#fff"
        },
        {
          "state": "FadeOn",
          "color": "#fff"
        },
        {
          "state": "FadeOn",
          "color": "#fff"
        },
        {
          "state": "Off",
          "color": "#fff"
        },
        {
          "state": "Off",
          "color": "#fff"
        },
        {
          "state": "Off",
          "color": "#fff"
        }
      ]
    },
    {
      "type": "light-step",
      "time": "2",
      "audioClipName": "Off",
      "audioVolume": 1,
      "lights": [
        {
          "state": "Off",
          "color": "#fff"
        },
        {
          "state": "Off",
          "color": "#fff"
        },
        {
          "state": "Off",
          "color": "#fff"
        },
        {
          "state": "FadeOff",
          "color": "#fff"
        },
        {
          "state": "FadeOff",
          "color": "#fff"
        },
        {
          "state": "Off",
          "color": "#fff"
        },
        {
          "state": "Off",
          "color": "#fff"
        },
        {
          "state": "Off",
          "color": "#fff"
        }
      ]
    }
  ]
}

... and after:

{
  "type": "light-item",
  "name": "Waiting",
  "ringSeqLooping": "true",
  "ringSeqHoldLast": "false",
  "ringSteps": [
    {
      "type": "light-step",
      "time": "1",
      "audioClipName": "Off",
      "audioVolume": "1",
      "lights": [
        {"state":"FadeOn","color":"#fff"},
        {"state":"Off","color":"#fff"},
        {"state":"Off","color":"#fff"},
        {"state":"Off","color":"#fff"},
        {"state":"Off","color":"#fff"},
        {"state":"Off","color":"#fff"},
        {"state":"Off","color":"#fff"},
        {"state":"Off","color":"#fff"}
      ]
    },
    {
      "type": "light-step",
      "time": "0.5",
      "audioClipName": "Off",
      "audioVolume": "1",
      "lights": [
        {"state":"FadeOff","color":"#fff"},
        {"state":"Off","color":"#fff"},
        {"state":"Off","color":"#fff"},
        {"state":"Off","color":"#fff"},
        {"state":"Off","color":"#fff"},
        {"state":"Off","color":"#fff"},
        {"state":"Off","color":"#fff"},
        {"state":"Off","color":"#fff"}
      ]
    }
  ],
  "stripSeqLooping": "true",
  "stripSeqHoldLast": "false",
  "stripSteps": [
    {
      "type": "light-step",
      "time": "2",
      "audioClipName": "Off",
      "audioVolume": "1",
      "lights": [
        {"state":"Off","color":"#fff"},
        {"state":"Off","color":"#fff"},
        {"state":"Off","color":"#fff"},
        {"state":"FadeOn","color":"#fff"},
        {"state":"FadeOn","color":"#fff"},
        {"state":"Off","color":"#fff"},
        {"state":"Off","color":"#fff"},
        {"state":"Off","color":"#fff"}
      ]
    },
    {
      "type": "light-step",
      "time": "2",
      "audioClipName": "Off",
      "audioVolume": "1",
      "lights": [
        {"state":"Off","color":"#fff"},
        {"state":"Off","color":"#fff"},
        {"state":"Off","color":"#fff"},
        {"state":"FadeOff","color":"#fff"},
        {"state":"FadeOff","color":"#fff"},
        {"state":"Off","color":"#fff"},
        {"state":"Off","color":"#fff"},
        {"state":"Off","color":"#fff"}
      ]
    }
  ]
}
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1 Comment

Ugh... I did notice some flaws just now (with booleans & numbers in particular) where it puts double-quotes around it. I guess it's up to you to decide if it's safe to do more global replacements across the entire JSON string to remove those edge cases.
1

Here is a solution I worked out which may be useful as a basis for doing something similar:

function labTab(ind){
    var tab,com,a;
    tab = "\t";
    com = [];
    for(a = 0; a < ind; a+=1){
        com.push(tab)
    }
    return com.join("");
}

function nsetEntry(tab,o,obj){
    return tab + '"'+ o + '":' + JSON.stringify(obj[o]);
}

function nsetObject(tab,o,obj,arr,ind){
    var start;
    start = tab + '"'+ o + '":{'; 
    return [start,nsetConstructor(obj[o],arr,ind)].join("\n") + "\n" + tab +"}"; 
}

function nsetConstructor(obj,arr,ind){
    var narr,tab,o,entry;
    narr = [];
    ind += 1;
    tab = labTab(ind);
    for(o in obj){
        if(obj[o].constructor === Object){
            entry = nsetObject(tab,o,obj,arr,ind);
            narr.push(entry); 
        }
        else{
            entry = nsetEntry(tab,o,obj);
            narr.push(entry);
        }
    }
    return narr.join(",\n");
}

function nsetLevels(obj,arr,ind){
    var o,start,tab;
    tab = labTab(ind);
    for(o in obj){
        if(obj[o].constructor === Object){
            entry = nsetObject(tab,o,obj,arr,ind);
            arr.push(entry); 
        }
        else{
            entry = nsetEntry(tab,o,obj);   
            arr.push(entry);
        }
    }
        return arr.join(",\n");
}

function nsetSave(){
    var json,o,ind,tab,obj,start,head,tail;
    json = [];
    for(o in nset){
        ind = 1;
        tab = labTab(ind);
        start = tab + '"'+ o + '":{';
        ind = 2;
        tab = labTab(ind);
        obj = nset[o];
        json.push([start,nsetLevels(obj,[],ind)].join("\n"))
    }
    head = "{\n";
    tail = "\n\t}\n}"
    FW.Write([head,json.join("\n\t},\n"),tail].join(""),"xset.json")
}

I could not figure out how to do replace as some members go down five levels,so I recreated the whole thing. The solution is not so hot but I got what I wanted to achieve - sample below:

    "Key":{
        "Label":{
            "Change":["Input"],
            "Repeat":{
                "Name":[["Top_level","All"],[[1,1]]],
                "Link":[["Top_level"],[[1,1]]]
            },
            "Delete":["Confirm","Cancel"],
            "Move":["Up","Down"],
            "Number":["Ascending","Descending"]
        },
        "Class":{
            "Change":["Input"]
        },
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Comments

1

I use JSON format for my app's configuration files. They are quite dissimilar and big enough, so different formatting rules are required to make them look better and readable. Unfortunately, provided answers are not flexible enough so I've made my own implementation called perfect-json to beautify JSON.

Consider that you want to format object in the question like this:

{
  "Repeat": {
    "Name": [
      ["Top_level", "All"],
      [[1, 1]]
    ],
    "Link": [
      ["Top_level"],
      [[1, 1]]
    ]
  },
  "Delete": ["Confirm", "Cancel"],
  "Move": ["Up", "Down"],
  "Number": [
    "Ascending",
    "Descending"
  ]
}

With perfect-json it can be achieved:

import perfectJson from 'perfect-json';

const obj = {
  Repeat: {
    Name: [['Top_level', 'All'], [[1, 1]]],
    Link: [['Top_level'], [[1, 1]]]
  },
  Delete: ['Confirm', 'Cancel'],
  Move: ['Up', 'Down'],
  Number: ['Ascending', 'Descending']
};

console.log(perfectJson(obj, {
  singleLine: ({ key, path, depth }) => {
    if (['Delete', 'Move'].includes(key)) {
      return true;
    }
    if (depth >= 3 && ['Name', 'Link'].includes(path[1])) {
      return true;
    }
    return false;
  }
}));

It's also easy to place each array on a single line as asked in the question:

console.log(perfectJson(obj, {
  indent: 4,
  singleLine: ({ value }) => Array.isArray(value)
}));
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1 Comment

Just in time for the question's tenth anniversary. Give me time to absorb it; I am sure it deserves an upvote.
1

I use prettier.

First install it:

npm i prettier

Then use it:

const prettier = require("prettier")

const obj = {"Repeat": {"Name":[["Top_level","All"],[[1,1]]],"Link": [["Top_level"],[[1,1]]]},"Delete": ["Confirm","Cancel"],"Move": ["Up","Down"],"Number": ["Ascending","Descending"]};

const json = prettier.format(JSON.stringify(obj), { parser: "json" });
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