Type Alias Merge<A, B, Options>

Merge<A, B, Options>: Or<IsAny<A>, IsAny<B>, any, Or<IsNever<A>, IsNever<B>, never, IsDisjoint<A, B> extends true
    ? A & B
    : [keyof A, keyof B] extends [infer KA extends KeyTypes, infer KB extends KeyTypes]
        ? IsLiteral<KA> extends true
            ? IsLiteral<KB> extends true
                ? [OptionalKeys<A>, OptionalKeys<B>] extends [infer PKA extends KeyTypes, infer PKB extends KeyTypes]
                    ? (IsNotNever<(...), (...)> extends infer R extends (...)
                        ? {
                            [k in (...)]?: (...)
                        }
                        : unknown) & (IsNotNever<(...), (...)> extends infer R extends (...)
                        ? {
                            [k in (...)]: (...)
                        }
                        : unknown) & (IsNotNever<(...), (...)> extends infer R extends (...)
                        ? {
                            [k in (...)]: (...)
                        }
                        : unknown) & (IsNotNever<(...), (...)> extends infer R extends (...)
                        ? {
                            [k in (...)]: (...)
                        }
                        : unknown)
                    : never
                : (IsNotNever<Exclude<(...), (...)>, {
                        selection: ...;
                    }> extends infer R extends KeyTypes
                    ? {
                        [k in R]: (...)[(...)]
                    }
                    : unknown) & (IsNotNever<Exclude<(...), (...)>, {
                        selection: ...;
                    }> extends infer R extends KeyTypes
                    ? {
                        [k in R]: (...)[(...)]
                    }
                    : unknown) & (IsNotNever<(...) & (...), {
                        selection: ...;
                    }> extends infer R extends KeyTypes
                    ? {
                        [k in R]: (...) | (...)
                    }
                    : unknown)
            : IsLiteral<KB> extends true
                ? {
                    [k in Exclude<KA, KB>]: A[k]
                } & {
                    [k in keyof B]: B[k]
                }
                : (IsNotNever<Exclude<(...), (...)>, {
                        selection: ...;
                    }> extends infer R extends KeyTypes
                    ? {
                        [k in R]: (...)[(...)]
                    }
                    : unknown) & (IsNotNever<Exclude<(...), (...)>, {
                        selection: ...;
                    }> extends infer R extends KeyTypes
                    ? {
                        [k in R]: (...)[(...)]
                    }
                    : unknown) & (IsNotNever<(...) & (...), {
                        selection: ...;
                    }> extends infer R extends KeyTypes
                    ? {
                        [k in R]: (...) | (...)
                    }
                    : unknown)
        : never>>

⚗️ transform 🔢 customizable

Merges type A and type B.

This type performs the same operations as { ...a, ...b } but at the type level.

It handles cases like A or B are Record, joining between required and optional props, etc.

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