No. 230 · Brutal · conditional types
Permutation
Implement `Permutation<T>` so it turns a union into the union of every tuple ordering of its members. `never` has exactly one permutation: the empty tuple.
Puzzle
permutation.tsStroke 1 of 5Not run yet
Replace ??? — your solution is checked against the cases below.
Checks
4Permutation<'a'>—→ ['a']Permutation<never>—→ []Permutation<'a' | 'b'>—→ ['a', 'b'] | ['b', 'a']Permutation<1 | 2>—→ [1, 2] | [2, 1]
How a check is judged Exact type equality, not assignability — an intersection is not the same as the flattened object.
How everyone did
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