Which required fields are missing

mediumvalidationPython

A form submission arrives as a bag of strings and the server checks it before touching the database.

A field is missing when its key is absent, or its value is empty or only whitespace.
Report them in the order the requirements were given, not the order the payload happens to be in.
Nothing required means nothing missing.

missing_fields(payload: map<string, string>, required: list<string>) → list<string>

Where you start

def missing_fields(payload: dict[str, str], required: list[str]) -> list[str]:

Call	Result
`missing_fields({"name": "Ada", "email": ""}, ["name", "email", "phone"])`	`["email", "phone"]`
`missing_fields({"name": " "}, ["name"])`	`["name"]`
`missing_fields({"name": "Ada"}, ["name"])`	`[]`
`missing_fields({}, [])`	`[]`

Walk the requirements, not the payload — that is what fixes the output order.

Reference solution in Python

def missing_fields(payload: dict[str, str], required: list[str]) -> list[str]:
    return [k for k in required if not payload.get(k, '').strip()]