Implement Promise.all From Scratch | Dataford Interview Questions

Manually implement Promise.all() from scratch without relying on built-in helpers.

For this coding exercise, the function receives a JSON-compatible list of already-settled values and must return a new list containing the same values in input order. Do not call built-in aggregation helpers such as all, map, or asyncio.gather.

Signature: promise_all(values)

The function must support an empty list, duplicate values, nested values, and falsy values without changing them.

Constraints

0 <= len(values) <= 10^4
Each value is a JSON-compatible scalar, list, or object
The input list must not be modified
The returned list must be a distinct list object
Results must preserve input order

Function Signature

def promise_all(values):

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