How to generate minimum-size Javascript object?

Question

How can I create a minimum-sized Javascript serialization of a Javascript object? Essentially a JSON.stringify with all unnecessary quotes removed. (Only basic JSON data types need to be supported, not Dates etc.)

For example, the JSON:

{
  "pi": 3.14,
  "e!": 4.26
}

would become:

{pi:3.14,"e!":4.26}

Edit: The result is not valid JSON, but is valid Javascript.

This is not a proper JSON, since the quotes are *mandatory*. — VLAZ, Oct 01 '19 at 19:42
`all unnecessary quotes` The spec says those quotes are very necessary. You are producing invalid JSON. — , Oct 01 '19 at 19:43
Write you own `stringify` method using `Object.entries(obj)`. Still, this sounds like an XY problem, so why do you need this? And you should add your own attempt to the question. — , Oct 01 '19 at 19:44
The confusion on my end was caused by `a minimum-sized Javascript serialization`. Serialized JS is referred to as JSON. If you want to produce JS *code*, I'd amend that line accordingly. — , Oct 01 '19 at 19:46
Possible duplicate of [JSON.stringify without quotes on properties?](https://stackoverflow.com/questions/11233498/json-stringify-without-quotes-on-properties) — Taha Paksu, Oct 01 '19 at 19:49
@TahaPaksu not a (complete) dupe. It only covers removing quotes from keys but doesn't minimise the space needed, nor does it (necessarily) check if the unquoted key is syntactically correct. — VLAZ, Oct 01 '19 at 19:53
Yea you are right, but the answers given there with a slight modification leads to the answer. Modifying the regexes there to exclude non-alphanumeric characters, and removing the spaces between keys and values should be enough. Well, I might give an answer.. — Taha Paksu, Oct 01 '19 at 19:58
`.replace(/"(\w+)":/g,"$1:")` will kill quotes on valid keys. — dandavis, Oct 01 '19 at 20:09

Taha Paksu · Accepted Answer · 2019-10-01T21:06:50.713

1

Copied from https://stackoverflow.com/a/11233515/916000 and modified:

function stringify(obj_from_json) {
  if (typeof obj_from_json !== "object") {
    return JSON.stringify(obj_from_json);
  } else {
    if (Array.isArray(obj_from_json)) {
      // if the array contains an object
      var arr = [];
      for (var i = 0, len = obj_from_json.length; i < len; i++) {
        arr.push(stringify(obj_from_json[i]));
      }
      return "[" + arr.join(",") + "]";
    } else {
      var props = Object
        .keys(obj_from_json)
        .map(function(key) {
          return (new RegExp(/^[1-9a-zA-Z_$][a-zA-Z0-9_$.]*$/).test(key) ? key : "\"" + key + "\"") + ":" + stringify(obj_from_json[key]);
        }).join(",");
      return "{" + props + "}";
    }
  }
}


console.log(stringify({
  "pi": 3.14,
  "e!": 4.26
}));

console.log(stringify([{
  "adjacencies": [{
    "nodeTo": "graphnode2",
    "nodeFrom": "graphnode1",
    "data": {
      "$color": "#557EAA"
    }
  }],
  "data": {
    "$color": "#EBB056",
    "$type": "triangle",
    "$dim": 9
  },
  "id": "graphnode1",
  "name": "graphnode1"
}, {
  "adjacencies": [],
  "data": {
    "$color": "#EBB056",
    "$type": "triangle",
    "$dim": 9
  },
  "id": "graphnode2",
  "name": "graphnode2"
}]));

console.log(stringify({1: 2}));
console.log(stringify({"000": 42}));
console.log(stringify({1.26: 42}));

Edit: Added object array support. Edit: Fixed array conversion.

edited Oct 01 '19 at 21:06

answered Oct 01 '19 at 20:06

Taha Paksu

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Now try it with `{1: 2}` or `{"1": 2}` – zerkms Oct 01 '19 at 20:46
If they are valid objects, yes I will. – Taha Paksu Oct 01 '19 at 20:50
The expected result is `{1:2}`, your code produces `{"1":2}`. After you fix it - it would be possible to find another edge case. And so on, and so forth. – zerkms Oct 01 '19 at 20:50
@zerkms, yes, added three more characters. – Taha Paksu Oct 01 '19 at 20:52
Now try `{"000": 42}`, the expected result is `{"000":42}` – zerkms Oct 01 '19 at 20:53
:D let me ask, why not `{000:42}` ? – Taha Paksu Oct 01 '19 at 20:54
Because `{000:42}` is identical to `{"0":42}`, `000` numeric literal is collapsed to `0` then stringified. `const o = {000: 42}; console.log(o["0"]);` – zerkms Oct 01 '19 at 20:55
Yea, I was expecting that. Do we need to create the perfect regex for this question? I can continue. – Taha Paksu Oct 01 '19 at 20:57
"Do we need to create the perfect regex for this question? I can continue." --- So can I. My point here is that one could take a parser instead of making up a regex that would always fail to cover some cases. – zerkms Oct 01 '19 at 20:58
Yes, waiting for another edge case Ivan. – Taha Paksu Oct 01 '19 at 20:58
Easy: `{1.42: 42}` – zerkms Oct 01 '19 at 20:59
is this even valid? – Taha Paksu Oct 01 '19 at 21:00
Why wouldn't it – zerkms Oct 01 '19 at 21:00
Are floats allowed as an object key? Let me check that. Very interesting. – Taha Paksu Oct 01 '19 at 21:01
https://www.ecma-international.org/ecma-262/10.0/#sec-object-initializer – zerkms Oct 01 '19 at 21:03
Cool, now let's switch to unicode `{aॏ: 42}` (but there are cases even with numbers still) – zerkms Oct 01 '19 at 21:08
:D all property types are strings, yes. Will you write anything that you can convert to a string? One could take a parser instead of a regex, that would fail too? – Taha Paksu Oct 01 '19 at 21:09
":D all property types are strings, yes" --- not all of them should be enclosed in strings. `aॏ` should not. "that would fail too?" --- if it's standard compliant - nope, it'd be okay. – zerkms Oct 01 '19 at 21:10

How to generate minimum-size Javascript object?

1 Answers1