Harden nested array transform
Hard JavaScript arena: map, filter, reduce, grouping, and immutable updates
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Missing prerequisites: javascript-easy-array-transform
Analytics events need to be grouped into a compact dashboard model. You are working inside a modern JavaScript application, and the arena only clears when the result is safe, deterministic, and explainable.
Learn to apply map, filter, reduce, grouping, and immutable updates in a modern JavaScript application while explaining the invariant, safety constraints, and hidden edge cases.
- Demonstrates map, filter, reduce, grouping, and immutable updates
- Handles the visible sample and hidden edge cases
- Keeps output deterministic and explainable
- Avoids unsafe dynamic execution
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