i tried to use flatten on the data retrieved from the database
but recieved this error

Unhandled rejection RangeError: Maximum call stack size exceeded
at new Boolean (native)
at Boolean.toString (native)
at /opt/lampp/htdocs/node-fropper/node_modules/flat/index.js:17:44
at Array.forEach (native)
at step (/opt/lampp/htdocs/node-fropper/node_modules/flat/index.js:14:25)
at /opt/lampp/htdocs/node-fropper/node_modules/flat/index.js:34:16
at Array.forEach (native)
at step (/opt/lampp/htdocs/node-fropper/node_modules/flat/index.js:14:25)
at /opt/lampp/htdocs/node-fropper/node_modules/flat/index.js:34:16
at Array.forEach (native)
at step (/opt/lampp/htdocs/node-fropper/node_modules/flat/index.js:14:25)
at /opt/lampp/htdocs/node-fropper/node_modules/flat/index.js:34:16
at Array.forEach (native)
at step (/opt/lampp/htdocs/node-fropper/node_modules/flat/index.js:14:25)
at /opt/lampp/htdocs/node-fropper/node_modules/flat/index.js:34:16
at Array.forEach (native)

9ff2125

Because I still have to use flat.flatten

I'm using this library in an F# project (transpiles to JS through using Fable). So unfortunately I have no JS repro (I'm not a JS dev).

unflatten is mostly working fine, but it seems to enter into infinite recursion on some objects. This happens even when there is seemingly nothing to unflatten.

I have an array of key-value pairs (React props) that I'm converting into an object, and then I'm using unflatten on this object.

This works fine for some prop arrays, such as this:

However, for others, such as this, it enters into an infinite recursion:

As you can see, in both cases, the original prop list (and thus the object) does not contain keys with the delimiter, and there are no sub-objects to recurse into (unless it does something with the function), so AFAIK unflatten shouldn't modify anything.

I have tried safe without any effect.

The weird thing is, the stack trace seems to come from the flatten function, which I do not call:

Hi,

I love your module, I've found many usecases for it already but now I've stumbled up what looks like a bug.

When I try to run this code:

lowerEnv =
  travis          : "true",
  travis_build_dir: "/home/travis/build/kvz/environmental",

nested = unflatten lowerEnv,
  object   : true
  delimiter: "_"

I get the following trace:

  5) Environmental config should be able handle travis environment:
     TypeError: Cannot set property 'dir' of undefined
    at /Users/kevin/workspace/environmental/node_modules/flat/index.js:83:21
    at Array.forEach (native)
    at unflatten (/Users/kevin/workspace/environmental/node_modules/flat/index.js:61:23)
    at Function.Environmental.config (/Users/kevin/workspace/environmental/src/environmental.coffee:29:14)
    at Context.<anonymous> (/Users/kevin/workspace/environmental/test/test-environmental.coffee:40:49)
    at Test.Runnable.run (/Users/kevin/workspace/environmental/node_modules/mocha/lib/runnable.js:196:15)
    at Runner.runTest (/Users/kevin/workspace/environmental/node_modules/mocha/lib/runner.js:374:10)
    at /Users/kevin/workspace/environmental/node_modules/mocha/lib/runner.js:452:12
    at next (/Users/kevin/workspace/environmental/node_modules/mocha/lib/runner.js:299:14)
    at /Users/kevin/workspace/environmental/node_modules/mocha/lib/runner.js:309:7
    at next (/Users/kevin/workspace/environmental/node_modules/mocha/lib/runner.js:247:23)
    at Object._onImmediate (/Users/kevin/workspace/environmental/node_modules/mocha/lib/runner.js:276:5)
    at processImmediate [as _immediateCallback] (timers.js:330:15)

My versions:

$ cat package.json |grep flat
    "flat": "1.2.1",
$ node --version
v0.10.22

Not sure if you're into coffeescript so I'll add the js snippet too:

var lowerEnv, nested;

lowerEnv = {
  travis: "true",
  travis_build_dir: "/home/travis/build/kvz/environmental"
};

nested = unflatten(lowerEnv, {
  object: true,
  delimiter: "_"
});

https://cdn.jsdelivr.net/npm/[email protected] can not be used without Node, because it contains at least require call, and using it in browser javascript console would be very convenient for debugging.

Could you publish a migration guide explaining how to correctly upgrade flat from v4 into v5?

At https://github.com/hughsk/flat/releases I see only an announcement of 5.0.0 with no info about breaking changes but I'd like to ensure.

[wrong repo]

Using $ for example:

unflatten({
    'TRAVIS': 'true',
    'TRAVIS_DIR': '/home/travis/build/kvz/environmental'
}, { overwrite: true })

// TRAVIS: {
//     $: 'true',
//     DIR: '/home/travis/build/kvz/environmental'
// }

When I have an object like {'a.b.0001': 'test'} after unflatten it becomes {a: {b: {1: 'test'}}}.
And it should be {a: {b: {'0001': 'test'}}}
I believe this to be bug.

I have a use case where i always have to unflatten a json object and i dont know if that object is already unflattened. If there is a number for an object key unflatten method create and array which replaces the original object and the array length matches the number plus one. With the last element being the element originally stored by the key. This happens only for nest objects not root level.

example:

flat.unflatten({ testing: { 12: 12 }}) => { testing: [,,,,,,,,,,,,12]}

Hi!

Great work on flat. I do have a question though: would it be possible to unflatten something back into a 'real' array? E.g.

{ "a": ["foo", "bar"] }

Now becomes

{ "a.0": "foo", "a.1": "bar"}

And that is great! But when using unflatten to reverse this, we get:

{"a":{"0":"foo","1":"bar"}}

Would it be possible to unflatten back into arrays instead of regular objects when numeric keys are found in the object?

console.log(flat.flatten({
  has: {
    value : 'someValue'
  },
  empty : {
    value : {
      nested: { }
    }
  }
}));

will return

{ 'has.value': 'someValue' }

instead the expected:

{ 'has.value': 'someValue', 'empty.value.nested': { } }

Edit:

To elaborate. It might seem as objects imply nesting, but if we don't account for empty objects, flatteining then deflattening an object will not preserve the original object structure.

In this example, doing flat.unflatten(flat.flatten(o)) will not retain the 'empty.value.nested' tree.

Hi, @hughsk 👋

Just thinking it would be cool to be able to npx flat some.json

Hey everyone,

It appears that when using maxDepth, only the first key value is being properly flattened. You can easily see this behaviour if you update the customDepth test to:

flatten({
  hello: {
    world: {
      again: 'good morning'
    }
  },
  lorem: {
    ipsum: {
      dolor: 'good evening'
    }
  }
}, {
  maxDepth: 2
})

Instead of the expected result:

{
  'hello.world': {
    again: 'good morning'
  },
  'lorem.ipsum': {
    dolor: 'good evening'
  }
}

You instead receive:

{
  'hello.world': { 
    again: 'good morning'
  },
  lorem: {
    ipsum: {
      dolor: 'good evening'
    }
  }
}

The issue appears to be that the currentDepth variable is only incremented, and never reset or decremented.

I have created a pull request #47 to remedy the situation.

this is a bit surprising to me, but apperently the order in which object entries are created affect the output of unflatten
see here:
https://tonicdev.com/lipp/flat-issue

a solution seems to be to itereate through the object keys sorted by length.

Shouldn't there be a way to escape those keys that have the delimiter inside?

Paths in json-pointer format use ~0 and ~1, which can be done in a one-liner.

I'm doing a major rewrite using ES6 on this flat#dev branch

The current implementation was getting out of hand and full of "garbage" to make it very difficult to make sense of. Let me know if you want to help out in this effort.
I'm planning to use flat in my json-operator

Hi, first of all thanks a lot for making flat, it's exactly what I was looking for.

I think I might have found an issue. When being passed this object:

{ filename: '/Users/kevin/metriks/rrds/nslookup/kvz-imac-home-4.local-nslookup.rrd',
     rrd_version: '0003',
     step: 300,
     last_update: 1392592863,
     header_size: 1832,
     'ds.8_8_8_8.index': 0,
     'ds.8_8_8_8.type': 'GAUGE',
     'ds.8_8_8_8.minimal_heartbeat': 600,
     'ds.8_8_8_8.min': 'NaN',
     'ds.8_8_8_8.max': 'NaN',
     'ds.8_8_8_8.last_ds': '19',
     'ds.8_8_8_8.value': 209,
     'ds.8_8_8_8.unknown_sec': 52,
     'ds.8_8_4_4.index': 1,
     'ds.8_8_4_4.type': 'GAUGE',
     'ds.8_8_4_4.minimal_heartbeat': 600,
     'ds.8_8_4_4.min': 'NaN',
     'ds.8_8_4_4.max': 'NaN',
     'ds.8_8_4_4.last_ds': '20',
     'ds.8_8_4_4.value': 220,
     'ds.8_8_4_4.unknown_sec': 52,
     'ds.4_2_2_2.index': 2,
     'ds.4_2_2_2.type': 'GAUGE',
     'ds.4_2_2_2.minimal_heartbeat': 600,
     'ds.4_2_2_2.min': 'NaN',
     'ds.4_2_2_2.max': 'NaN',
     'ds.4_2_2_2.last_ds': '122',
     'ds.4_2_2_2.value': 1342,
     'ds.4_2_2_2.unknown_sec': 52,
     'ds.208_67_222_222.index': 3,
     'ds.208_67_222_222.type': 'GAUGE',
     'ds.208_67_222_222.minimal_heartbeat': 600,
     'ds.208_67_222_222.min': 'NaN',
     'ds.208_67_222_222.max': 'NaN',
     'ds.208_67_222_222.last_ds': '18',
     'ds.208_67_222_222.value': 198,
     'ds.208_67_222_222.unknown_sec': 52,
     'ds.172_16_0_23.index': 4,
     'ds.172_16_0_23.type': 'GAUGE',
     'ds.172_16_0_23.minimal_heartbeat': 600,
     'ds.172_16_0_23.min': 'NaN',
     'ds.172_16_0_23.max': 'NaN',
     'ds.172_16_0_23.last_ds': '-1',
     'ds.172_16_0_23.value': -11,
     'ds.172_16_0_23.unknown_sec': 52,
     'rra.0.cf': 'AVERAGE',
     'rra.0.rows': 300,
     'rra.0.cur_row': 215,
     'rra.0.pdp_per_row': 1,
     'rra.0.xff': 0.5,
     'rra.0.cdp_prep.0.value': 'NaN',
     'rra.0.cdp_prep.0.unknown_datapoints': 0,
     'rra.0.cdp_prep.1.value': 'NaN',
     'rra.0.cdp_prep.1.unknown_datapoints': 0,
     'rra.0.cdp_prep.2.value': 'NaN',
     'rra.0.cdp_prep.2.unknown_datapoints': 0,
     'rra.0.cdp_prep.3.value': 'NaN',
     'rra.0.cdp_prep.3.unknown_datapoints': 0,
     'rra.0.cdp_prep.4.value': 'NaN',
     'rra.0.cdp_prep.4.unknown_datapoints': 0,
     '': '' }

The resulting unflattened structure looks like this:

{ filename: '/Users/kevin/metriks/rrds/nslookup/kvz-imac-home-4.local-nslookup.rrd',
     rrd_version: '0003',
     step: 300,
     last_update: 1392592863,
     header_size: 1832,
     ds:
      [ ,
        ,
        ,
        ,
        [Object],
        ,
        ,
        ,
        [Object],
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        [Object],
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        ,
        [Object] ],
     rra: [ [Object] ],
     '': '' }

My guess is that flat too eagerly tries to look for numbers in keys as it wants to forge arrays for those.

Let me know if I'm overlooking something.

Best,
Kevin

IMHO, {object: true} should be the default. I spent some time trying to figure out why I had an array containing 8004 * null... I way simply flattening an object containing this key: messages.upsells.errors.8005

Thanks for the good work!

I'm using flat module for preparing object to store data in Redis DB. (Redis doesn't allow array and nested object )
Now, the Issue is Flat doesn't do anything to blank array.
E.g.

{
    a: [],
    a1: {
        a11: 1
    }
    b: 'test',
    c: 12
}
is flatten to 
{
    a: [],
    a1.a11: 1,
    b: "test",
    c: 12,
}

this gives me error on Redis. Can Flat module help me with this?

Hey @hughsk

We are using your flat module at Echo. Thanks a lot for the amazing work!

I got a bit inspired today to try to make the flatten function as a one-liner. Have a look below:

const flatten = (c, d = '.') => {
  const r = {};
  (function f(o, p) {
      Object.keys(o).forEach(k => (o[k] && typeof o[k] === 'object' ? f(o[k], p ? `${p}${d}${k}` : k) : (r[p ? `${p}${d}${k}` : k] = o[k])));
  }(c));
  return r;
};

Tests:

  it('flatten', () => {
    let $in = { a: 1, b: { c: 2, d: 2, e: { f: 3, g: 3, h: 3, j: { k: { l: true } } } } };
    let $out = { a: 1, 'b.c': 2, 'b.d': 2, 'b.e.f': 3, 'b.e.g': 3, 'b.e.h': 3, 'b.e.j.k.l': true };
    expect(flatten($in)).to.deep.equal($out);

    $in = ['a', { b: 1 }, { c: 2, d: 2 }];
    $out = { 0: 'a', '1.b': 1, '2.c': 2, '2.d': 2 };
    expect(flatten($in)).to.deep.equal($out);

    $in = { a: { b: 1, c: 1 } };
    $out = { 'a/b': 1, 'a/c': 1 };
    expect(flatten($in, '/')).to.deep.equal($out);

    $in = { x: 1, y: null, z: undefined };
    $out = { x: 1, y: null, z: undefined };
    expect(flatten($in)).to.deep.equal($out);
  });

Original code here https://github.com/RomansBermans/transformer

const test = flatten(12345);
console.log(test);

On React Native > iOS, this returns {}. But on React Native > Android, this errors with:

TypeError: Requested keys of a value that is not an object.

Now flatjs suggests, that it uses in nodejs. But would be pretty if you check AMD and browser too.

It may just be me doing something stupid however I'm converting the following:

{ app_preferences: { test: 1 }, settings: { network: { appnetwork: { device: '/dev/eth1' }, devnetwork: { device: '/dev/eth0' } } } }

The object flatten is producing is this:

{"0":123,"1":10,"2":32,"3":110,"4":100,"5":109,"6":95,"7":112,"8":114,"9":101,"10":102,"11":101,"12":114,"13":101,"14":110,"15":99,"16":101,"17":115,"18":58,"19":32,"20":123,"21":10,"22":32,"23":32,"24":32,"25":116,"26":101,"27":115,"28":116,"29":58,"30":32,"31":49,"32":10,"33":32,"34":125,"35":44,"36":10,"37":32,"38":115,"39":101,"40":116,"41":116,"42":105,"43":110,"44":103,"45":115,"46":58,"47":32,"48":123,"49":10,"50":32,"51":32,"52":32,"53":110,"54":101,"55":116,"56":119,"57":111,"58":114,"59":107,"60":58,"61":32,"62":123,"63":10,"64":32,"65":32,"66":32,"67":32,"68":32,"69":110,"70":100,"71":109,"72":110,"73":101,"74":116,"75":119,"76":111,"77":114,"78":107,"79":58,"80":32,"81":123,"82":10,"83":32,"84":32,"85":32,"86":32,"87":32,"88":32,"89":32,"90":100,"91":101,"92":118,"93":105,"94":99,"95":101,"96":58,"97":32,"98":39,"99":47,"100":100,"101":101,"102":118,"103":47,"104":101,"105":116,"106":104,"107":49,"108":39,"109":10,"110":32,"111":32,"112":32,"113":32,"114":32,"115":125,"116":44,"117":10,"118":32,"119":32,"120":32,"121":32,"122":32,"123":111,"124":116,"125":97,"126":110,"127":101,"128":116,"129":119,"130":111,"131":114,"132":107,"133":58,"134":32,"135":123,"136":10,"137":32,"138":32,"139":32,"140":32,"141":32,"142":32,"143":32,"144":100,"145":101,"146":118,"147":105,"148":99,"149":101,"150":58,"151":32,"152":39,"153":47,"154":100,"155":101,"156":118,"157":47,"158":101,"159":116,"160":104,"161":48,"162":39,"163":10,"164":32,"165":32,"166":32,"167":32,"168":32,"169":125,"170":10,"171":32,"172":32,"173":32,"174":125,"175":10,"176":32,"177":125,"178":10,"179":125,"180":10,"181":10}

Code being used:

`
const fs = require('fs');

var flatten = require('flat');

var loadconfig = fs.readFileSync('config.json');

var config_params = flatten(loadconfig);

console.log("%j", config_params);

`

How to exclude unflattening the values of the key?

    'files.exclude': {
        default: { '**/.git': true, '**/.svn': true, '**/.hg': true, '**/CVS': true, '**/.DS_Store': true },
  }

Output:

  { files: {
     exclude: {
      "default": Object {
        "**/": Object {
          "DS_Store": true,
          "git": true,
          "hg": true,
          "svn": true,
        },
        "**/CVS": true,
      }
 }
} 

Expectation

{ files: { exclude: { default: { '**/.git': true, '**/.svn': true, '**/.hg': true, '**/CVS': true, '**/.DS_Store': true }}}}

<--- Last few GCs --->

[4742:0x110000000] 13658 ms: Mark-sweep 1388.1 (1425.4) -> 1387.6 (1425.4) MB, 94.9 / 0.0 ms (average mu = 0.144, current mu = 0.047) allocation failure GC in old space requested
[4742:0x110000000] 13907 ms: Mark-sweep 1387.6 (1425.4) -> 1387.6 (1425.9) MB, 233.0 / 0.0 ms (average mu = 0.095, current mu = 0.062) allocation failure GC in old space requested

<--- JS stacktrace --->

==== JS stack trace =========================================

0: ExitFrame [pc: 0x1fd429adbe3d]

Security context: 0x350268d1e6e9
1: step [0x350214a022c9] [/Volumes/Root/Users/Elvis/Desktop/buybuybuy/project/packages/LoginService/node_modules/flat/index.js:~14] [pc=0x1fd42a19fcef](this=0x35020a88d461 ,object=0x350214a18891 <JSArray[15]>,prev=0x3502c1782229 <Very long string[3614]>,currentDepth=400)
2: step [0x350214a022c9] [/Volumes/Root/Users/Elvis/Desktop/buy...

FATAL ERROR: Ineffective mark-compacts near heap limit Allocation failed - JavaScript heap out of memory
1: 0x10003cf99 node::Abort() [/usr/local/bin/node]
2: 0x10003d1a3 node::OnFatalError(char const*, char const*) [/usr/local/bin/node]
3: 0x1001b7835 v8::internal::V8::FatalProcessOutOfMemory(v8::internal::Isolate*, char const*, bool) [/usr/local/bin/node]
4: 0x100585682 v8::internal::Heap::FatalProcessOutOfMemory(char const*) [/usr/local/bin/node]
5: 0x100588155 v8::internal::Heap::CheckIneffectiveMarkCompact(unsigned long, double) [/usr/local/bin/node]
6: 0x100583fff v8::internal::Heap::PerformGarbageCollection(v8::internal::GarbageCollector, v8::GCCallbackFlags) [/usr/local/bin/node]
7: 0x1005821d4 v8::internal::Heap::CollectGarbage(v8::internal::AllocationSpace, v8::internal::GarbageCollectionReason, v8::GCCallbackFlags) [/usr/local/bin/node]
8: 0x10058ea6c v8::internal::Heap::AllocateRawWithLigthRetry(int, v8::internal::AllocationSpace, v8::internal::AllocationAlignment) [/usr/local/bin/node]
9: 0x10058eaef v8::internal::Heap::AllocateRawWithRetryOrFail(int, v8::internal::AllocationSpace, v8::internal::AllocationAlignment) [/usr/local/bin/node]
10: 0x100573d8e v8::internal::Handlev8::internal::String v8::internal::Factory::AllocateInternalizedStringImpl<true, v8::internal::Handlev8::internal::String >(v8::internal::Handlev8::internal::String, int, unsigned int) [/usr/local/bin/node]
11: 0x1006d7ae5 v8::internal::InternalizedStringKey::AsHandle(v8::internal::Isolate*) [/usr/local/bin/node]
12: 0x1006c0a90 v8::internal::StringTable::AddKeyNoResize(v8::internal::Isolate*, v8::internal::StringTableKey*) [/usr/local/bin/node]
13: 0x1006c0430 v8::internal::StringTable::LookupString(v8::internal::Isolate*, v8::internal::Handlev8::internal::String) [/usr/local/bin/node]
14: 0x100240d50 v8::internal::LookupIterator::LookupIterator(v8::internal::Handlev8::internal::Object, v8::internal::Handlev8::internal::Name, v8::internal::LookupIterator::Configuration) [/usr/local/bin/node]
15: 0x100675ce5 v8::internal::LookupIterator::PropertyOrElement(v8::internal::Isolate*, v8::internal::Handlev8::internal::Object, v8::internal::Handlev8::internal::Object, bool*, v8::internal::LookupIterator::Configuration) [/usr/local/bin/node]
16: 0x100803fd3 v8::internal::Runtime::SetObjectProperty(v8::internal::Isolate*, v8::internal::Handlev8::internal::Object, v8::internal::Handlev8::internal::Object, v8::internal::Handlev8::internal::Object, v8::internal::LanguageMode) [/usr/local/bin/node]
17: 0x100807863 v8::internal::Runtime_SetProperty(int, v8::internal::Object**, v8::internal::Isolate*) [/usr/local/bin/node]
18: 0x1fd429adbe3d
19: 0x1fd42a19fcef

hi there,

I've come across what I believe is a bug. I start with an object that has an array of strings nested a couple levels from the top (the attachments array).

But, once I flatten the object and save it in MongoDB, the result is that the customers[0].names[0].attachments array has been coerced into an object for some reason:

BEFORE

{
  _id : 1234567890,
  customers : [
    {
      names : [
        {
          type : 'legal',
          value : 'John Smith',
          attachments : [
            'abcdefg-12345'
          ]
        }
      ]
    }
  ]
}

AFTER

{
  _id : 1234567890,
  customers : [
    {
      names : [
        {
          type : 'legal',
          value : 'John Smith',
          attachments : {
            "0" : 'abcdefg-12345'
          }
        }
      ]
    }
  ]
}

Is this the expected behaviour of flat?

Hello,

First thanks for such a great library!

I was wondering if there is a config that will allow me to flatten my JSON file starting at a specific depth instead of always flattening from the root to leaf.

Use case:

Input:

flatten(
  {
    "foo": {
      "bar": {
        "a": 1,
        "b": 2,
        "c": 3
      }
    },
    "amaze": {
      "muppet": "wow",
      "haw": "maw"
    }
  }
);

Output:

{
  "foo": {
    "bar.a": 1,
    "bar.b": 2,
    "bar.c": 3,
  },
  "amaze": {
    "muppet": "wow",
    "haw": "maw"
  }
}

Looking at the current options it seems like this would be the opposite of maxDepth. Maybe a minDepth option.

need to https://www.npmjs.com/package/destroy-circular or something

Hello, if I use this:

message = 20
try data = flatten JSON.parse(message)

on Node v0.10.26 returns "undefined"
on Node v4.4.1 returns "{}"

I'm looking for a way to preserve keys that have .s in to use the same syntax as lodash's set/get.

Ideally something like this:

// Input
{
  some: {
    'key.with.dots': value
  }
}

// Output
{
  some['key.with.dots']: value
}

The problem I've found with using the transformKey option is they still get the . joining them.

I have this:

const flatData = flatten(data, {
  transformKey: key => (key.includes('.') ? `['${key}']` : key),
});

But the output looks like this. (extra . after some)

{
  some.['key.with.dots']: value
}

I've worked around the issue for now by looping through the flattend data and doing a string replace on .[ with [.

const fixedData = Object.entries(flatData).reduce((acc, [key, value]) => {
  const newKey = key.includes('.[') ? key.replace('.[', '[') : key;
  acc[newKey] = value;
  return acc;
}, {});

Would be great if flat can be imported as ES modules.

Ref: jsverse/transloco#301

Proposal

Support passing (string, string) => string function as a delimiter option.

For example, for object:

{
  first: {
    second: "hello"
  }
}

and delimiter:

(left, right) => left + right.charAt(0).toUpperCase() + right.slice(1);

it will produce camel case names:

{
  firstSecond: "hello"
}

You really should add a changelog file or at least release notes on the releases tab in GitHub to communicate your changes to everyone.

This allows for dot notation after the flatten. Simple fix. Thanks for a great utility!

A single arrow function is breaking functionality in < IE11.

target = Object.keys(target).reduce((result, key) =>

I am using this module in the browser for a angular/typescript app.

Hi, I have a unique use-case, I am currently building a dynamic table based on an object's keys. So this does not work correctly when the object has an array associated with it. Would it be possible to add an additional parameter to specify that arrays should be strings with the safe option associated?

for example:
`flatten({
title:'Hello world',
countries: ['ZAF','USA','GRL']
}, {
safe:true,
arraytostring:true
});

//output:
// {
// title:'Hello World',
// countries: '["ZAF","USA","GRL"]'
`

If you do not want to add this functionality to your repo, can I clone the project and add this for my specific use-case?

Issue:

Suppose I have the following object

{ "foo": { "bar": "hello-world" }, "data": {}, "tests": [] }

I would expect this object to be flattened if I need it for some sort of operation which does not support complex objects.
Perhaps it would be flattened in this way
{ "foo.bar": "hello-world", "data": "{}", "tests": "[]" }

Or, perhaps there is a better way to do this; but, what actually occurs is the following

{ "foo.bar": "hello-world", "data": {}, "tests": [] }

Where, in reality, this has not been flattened. There still exists nested objects, they are just empty.

What character sets are supported? Seems to abort with words like "apéritif"

This would complement maxDepth in a coherent way.

minDepth

Number of nested objects to skip before flattening others.

var flatten = require('flat')

flatten({
    key1: {
        keyA: 'valueI'
    },
    key2: {
        keyB: 'valueII'
    },
    key3: { a: { b: { c: 2 } } }
}, { minDepth: 1 })

// {
//   key1: { keyA: 'valueI' },
//   key2: { keyB: 'valueII' },
//   key3: { a: { 'b.c': 2 } }
// }

// ok
flat.unflatten({ 'a.b': 'c' }); // { a: { b: 'c' } }
// not ok
flat.unflatten({ a: null, 'a.b': 'c' }); // TypeError: Cannot set property 'b' of null

Probably, it happens because of 'object' === typeof null, but I didn't see the source

If possible, can you please add a LICENSE file, or place the BSD license in the README? Thank you!

const a = {
  __proto__: {
    fun: () => 'foo',
    __proto__: {
      fun: () => 'bar',
    },
  },
};

Should flatten to

const a = {
  '__proto__.fun': () => 'foo',
  '__proto__.__proto__.fun': () => 'bar',
};

We can have a flag like extraKeys: ['__proto__']

var flat = require("flat");

var data  = {
  "object": {"0": "a", "1": "b"}
};

console.log(flat.unflatten(flat.flatten(data)));

Outputs

{ object: [ 'a', 'b' ] }

Not sure how often people would use integers as object keys, but is a valid case nonetheless.

I realize that yes, you can pass {object:true} to unflatten, and it will not automatically assume it's an array, but then you get the opposite behavior. i.e. "Arrays turn into objects".

A more generic solution would be to use square brackets in the flattened format, where:

object[0], and object.0 imply different data structures.

var flat = require('flat')

var obj = [{a: 1}, {b: 2}]
var _obj = flat.flatten(obj)
console.log(_obj)// { '0.a': 1, '1.b': 2 }
console.log(flat.unflatten(_obj))// { '0': { a: 1 }, '1': { b: 2 } }

I want [{a: 1}, {b: 2}], but not { '0': { a: 1 }, '1': { b: 2 } }

I have tried the below code, where "c.d": 20 turns into "c: { d: 20 }". I have used {object:true} which also didnt help me.

var flatten = require('flat'),
unflatten = require('flat').unflatten;

var obj1 = flatten({a: 10, b: 15, "c.d": 20, e: 50})

var res = flatten(obj1)
console.log(res) //{ a: 10, b: 15, 'c.d': 20, e: 50 }
var fin = unflatten(res,{object: true});
console.log(fin) //{ a: 10, b: 15, c: { d: 20 }, e: 50 }

I'd like to have your formal consent to add this dependency to a project which is licensed under the MIT license.

Project:
expressive-middleware

License:
MIT License

Hello Community,

Have you thought about adding a function option that could act as a flat stop condition?

I'm having issues with flattening an ObjectId (from MongoDB). Currently Flat will split this in bsonType and id (with unknown chars).

If I could pass down a function to Flat that would receive the object to process and decide if it should be processed or continue it would be great no?

What do you think?

I'm available to create a PR if you feel that this is interesting.