Type Advance types - array intersection

gistfile1.ts

// Construct a type that checks if 2 array are interscting

type ToUnion<T extends unknown[]> = T[number];

type IntersectionArrays<T extends any[], U extends any[]> =  T["length"] extends 0 ? true :
  { [K in ToUnion<T>]: K extends ToUnion<U> ? false : true }[ToUnion<T>] extends true ? true : never

// Will resolve true since no intersection found
type A = IntersectionArrays<[1], [2]>

// Will resolve never since both array have the item "1" inside
type B = IntersectionArrays<[1], [1]>

// You can also twick the type to aslo return the actual araay passed as a type

type IntersectionArrays<T extends any[], U extends any[]> =
  { [K in ToUnion<T>]: K extends ToUnion<U> ? false : true }[ToUnion<T>] extends true ? T extends (infer U)[] ? U[] : never : never

// will resolve to (1)[]
type A = IntersectionArrays<[1], [2]>