[Compound] Colons with numeric labels in wrong order

[DrizzleatDusk]

Describe the bug

I find a disarrangement of the columns when I want to display a structured numpy array.

To Reproduce

The bug can be reproduced by the following python code.

# create a structured array.
dtype = np.dtype(
    {"names": ['1', '0', '2'], "formats": [np.float64, np.float64, np.float64]}
)
data = np.array([(1.0, 2.0, 3.0), (4.0, 5.0, 6.0)], dtype=dtype)

# save.
file = h5py.File("./test.h5", 'w')
file.create_dataset("a", data=data, dtype=dtype)
file.close()

Expected behaviour

We can read from the file as follows:

file = h5py.File("./test.h5", 'r')
print(file["a"]["0"])     #[2. 5.]
print(file["a"]["1"])     #[1. 4.]
print(file["a"]["2"])     #[3. 6.]
file.close()

Screenshots

There is no problem using non numeric string. But in the above example, it seems that the columns are rearranged according to the values of the array index, which I think is a confusing behavior.

Context

I run the above example in the vscode plugin. (h5web.vscode-h5web v0.1.7)

[loichuder]

Thanks for the report, there is indeed something fishy there.

I changed slightly the formats to have different dtypes for each field

dtype = np.dtype(
    {"names": ["1", "0", "2"], "formats": [np.float64, np.int32, np.uint8]}
)

and it seems that these are parsed properly by h5wasm but the order changed:

  "type": {
    "class": "Compound",
    "fields": {
      "0": {
        "class": "Integer",
        "endianness": "little-endian",
        "size": 32
      },
      "1": {
        "class": "Float",
        "endianness": "little-endian",
        "size": 64
      },
      "2": {
        "class": "Integer (unsigned)",
        "endianness": "little-endian",
        "size": 8
      }
    }
  },

I wonder if this is the cause of the incorrect display by H5Web.

Interestingly, using names that cannot be converted to numbers gives the expected result:

dtype = np.dtype(
    {"names": ["1ff", "0ff", "2ff"], "formats": [np.float64, np.int32, np.uint8]}
)

Fields were not reordered in this case which may be linked:

  "type": {
    "class": "Compound",
    "fields": {
      "1ff": {
        "class": "Float",
        "endianness": "little-endian",
        "size": 64
      },
      "0ff": {
        "class": "Integer",
        "endianness": "little-endian",
        "size": 32
      },
      "2ff": {
        "class": "Integer (unsigned)",
        "endianness": "little-endian",
        "size": 8
      }
    }
  },