flatten nested object properties for json array data preview display

[AiaRup]

Hello,
I tried to view a JSON in the data-preview but it appears as [object object].

The raw data looks like this (mongo document):

When I preview only one document it looks like this as a preview:

When I want to look at several documents in a JSON file I see the [object object]:

I don't know if it is a bug or I need to configure something?
Thank a lot!

[RandomFractals]

@AiaRup your first example is just a json config that is converted to flat properties list per this note in docs: https://github.com/RandomFractals/vscode-data-preview#data-preview--files-loading-details

Your 2nd example is most likely a json array. However, that json document has nested object properties for the _id and group properties & data preview doesn't try to expend them.

Perhaps, it could be improved for the latter use case.

Current json array display works best with json docs that contain flat objects, such as in this example: https://github.com/RandomFractals/vscode-data-preview/blob/master/data/json/cars.json

[RandomFractals]

the only sensible solution for this use case I can propose and try to implement is flattening those objects, so that your json array grid will have the following headers:

_id.$oid, resource, actions, group.$oid

this is due to the fact that json can be hierarchical, but we are displaying that data in a grid of rows and columns, which is a flat 2 dimensional format :(

[AiaRup]

the only sensible solution for this use case I can propose and try to implement is flattening those objects, so that your json array grid will have the following headers:

_id.$oid, resource, actions, group.$oid

this is due to the fact that json can be hierarchical, but we are displaying that data in a grid of rows and columns, which is a flat 2 dimensional format :(

It seems perfect, thanks a lot for all your hard work!

[RandomFractals]

btw, data preview also supports .jsonl format, if you just want to create a single json doc using cat Unix command and then preview that json data dump :)

see issue #159 for more info

[RandomFractals]

I am only bringing up jsonl since that and csv/tsv data formats will be the first to get data streaming implemented in the next v. update this month most likely.

With data streaming you'll be able to view hundreds of thousands of data rows. More info here: #167

So, if you script your mongo db data dump that way, you'll be good to go and see more data loaded faster in the next data preview ext. update.

[RandomFractals]

@AiaRup btw, I also have mongoDB data connector penciled in for the data preview wish/todo list, but I don't think I'll get to it this year: #26

Thumb it up & if I see more devs interested in that feature, I might move it up the implementation list :)

[AiaRup]

I am only bringing up jsonl since that and csv/tsv data formats will be the first to get data streaming implemented in the next v. update this month most likely.

With data streaming you'll be able to view hundreds of thousands of data rows. More info here: #167

So, if you script your mongo db data dump that way, you'll be good to go and see more data loaded faster in the next data preview ext. update.

I will check it out, thank you so much!

[RandomFractals]

might try using json-2-csv for this prior to passing nested json objects to the grid view display which is tabular ...

https://github.com/mrodrig/json-2-csv

[RandomFractals]

actually, might try this json-spread lib instead: https://github.com/gone369/json-spread

or: https://github.com/hughsk/flat

[RandomFractals]

probably the best we can do to flatten json arrays with nested objects for now: