Problem Statement/Rationale

Importing from JSON file a document that looks something like this:

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

will result in the property foo being converted to the array during the import

Steps to Reproduce

Create a json file with documents that have mixed number-like and string keys

Expected Results

Document is uploaded, all values are present in the imported documents, objects are still objects

Actual Results

If a document has mixed keys, it will be converted to an array and all string keys will be lost

Additional Notes

Here's the root cause: https://github.com/mongodb-js/compass/blob/0c6483f7aaea2d9e00a6d09520428111fc808b09/packages/compass-import-export/src/utils/import-apply-types-and-projection.js#L66

If this set encounters a path that ends in a number-like key, it will create an array, if not, it will create an object. If an object has mixed keys, first one will always be a number-like one in this part of the code