1type Diff<T extends keyof any, U extends keyof any> = 2 ({ [P in T]: P } & { [P in U]: never } & { [x: string]: never })[T] 3type Omit<U, K extends keyof U> = Pick<U, Diff<keyof U, K>> 4type Omit1<U, K extends keyof U> = Pick<U, Diff<keyof U, K>>; 5// is in fact an equivalent of 6 7type Omit2<T, K extends keyof T> = {[P in Diff<keyof T, K>]: T[P]}; 8 9type O = Omit<{ a: number, b: string }, 'a'> 10export const o: O = { b: '' } 11