Your question is Efficient Nested JSON Parsing. Start with the requirements on the right.
Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.
Wissen Technology data pipelines receive JSON payloads with nested objects and arrays. Implement flatten_json to convert any JSON-compatible value into a dictionary mapping each leaf path to its value, without using recursive function calls.
Input is one JSON-compatible Python value: a dictionary, list, string, number, boolean, or None. Object keys contain only letters, digits, and underscores. Return a dictionary whose keys are paths and whose values are scalar JSON values. Use $ for the root, .key for object fields, and [index] for array elements. None, booleans, strings, and numbers are leaves. Empty dictionaries and lists are also emitted as values at their own paths.
The implementation must use an explicit stack so it remains safe for nesting depths that could exceed Python's recursion limit. The input must not be modified.
def flatten_json(data):