stringify: Drop Array index, when possible

[kenperkins]

I noticed that the following happens on an array:

var qs = require('qs');

qs.stringify({ ids: [1,2,3,4,5,6] });

Output:

ids[0]=1&ids[1]=2&ids[2]=3&ids[3]=4&ids[4]=5&ids[5]=6

Is there any way to stringify without the index location? i.e.:

ids=1&ids=2&ids=3&ids=4&ids=5&ids=6

[kenperkins]

Running this command yields a different output than input:

qs.stringify(qs.parse('id=1&id=2'));

output:

'id[0]=1&id[1]=2'

[tj]

yeah +1 on fixing that, it should definitely not result in different output haha

[buschtoens]

This behaviour makes sense, as arrays can contain empty (undefined) slots.

var arr = [0, 1, 2, 3, 4, 5];
delete arr[3];
console.log(arr); // [0, 1, 2, undefined, 4, 5]

If we'd now blindly convert arrays we end up with arr=0&arr=1&arr=2&arr=4&arr=5, which has wrong indexing, as it translates back to [0, 1, 2, 4, 5]. The empty slot is missing.

However, you have a valid point. We should always try to produce the shortest possible but valid output we can.
So we can still implement this, if we check the arrays for consistency first.

[kenperkins]

The problem is both arr=0 and arr[0] may be valid output. The latter matters if order is critical.

This bug was to try and figure out how to accommodate both output formats.

[mxk1235]

we are currently blocked by this. can I get an update on a workaround?

more specifically, we would like to have

require('qs').stringify( { 'key[]' : [ 1, 2 ] } );
'key%5B%5D=1&key%5B%5D=2'

what's the correct way of doing it?

[kenperkins]

Thanks for refreshing this issue @mxk1235. The issue here is that currently qs.stringify is opinionated for how it serializes an array. And it shouldn't be. Perhaps the default should stay as is (to not break back-compat) but it should be perfectly allowable to serialized without index locations.

[mxk1235]

any idea on the timeframe for fixing this?

[myndzi]

I also have a need for repeating indexes due to the structure of an API I need to use. The 'request' module uses qs to create its query strings, so I tracked it back to here. Specifically, it would be extremely helpful to have the following be possible:

qs.stringify({ key: ['val1', 'val2', 'val3', ...] });

outputs:

key=val1&key=val2&key=val3...

[jkarttunen]

+1 for fixing this

[pietia]

We've managed to fix this issue by monkey patching Request:

var querystring = require('querystring');
request.Request.prototype.form = function (form) {
  if (form) {
    this.setHeader('content-type', 'application/x-www-form-urlencoded; charset=utf-8')
    this.body = querystring.stringify(form).toString('utf8');
    return this
  }
  // create form-data object
  this._form = new FormData();
  return this._form;
};

[rlidwka]

@jkarttunen , @pietia , this repository is moved to https://github.com/hapijs/qs . If you want this implemented, please ask there instead.

[kenperkins]

Uh. why do the deprecation this way instead of via github move repo?

[rlidwka]

No idea, you might find some answers here: #113