在我看来，联合类型在这种情况下是最好的选择:

interface Employee{
   id: number;
   name: string;
   salary: number | null;
}

// Both cases are valid
let employe1: Employee = { id: 1, name: 'John', salary: 100 };
let employe2: Employee = { id: 1, name: 'John', salary: null };

编辑:为了使其按预期工作，您应该在tsconfig中启用strictNullChecks。

type WithNullableFields<T, Fields> = {
  [K in keyof T]: K extends Fields 
    ? T[K] | null | undefined
    : T[K]
}

let employeeWithNullableSalary: WithNullableFields<Employee, "salary"> = {
  id: 1,
  name: "John",
  salary: null
}

或者你可以关闭strictNullChecks;)

反过来说:

type WithNonNullableFields<T, Fields> = {
  [K in keyof T]: K extends Fields
    ? NonNullable<T[K]>
    : T[K]
}

在我看来，联合类型在这种情况下是最好的选择:

interface Employee{
   id: number;
   name: string;
   salary: number | null;
}

// Both cases are valid
let employe1: Employee = { id: 1, name: 'John', salary: 100 };
let employe2: Employee = { id: 1, name: 'John', salary: null };

编辑:为了使其按预期工作，您应该在tsconfig中启用strictNullChecks。

为了更像c#，可以这样定义Nullable类型:

type Nullable<T> = T | null;

interface Employee{
   id: number;
   name: string;
   salary: Nullable<number>;
}

奖金:

为了使Nullable表现得像一个内置Typescript类型，在根源文件夹的global.d.ts定义文件中定义它。这个路径适合我:/src/global.d.ts

type MyProps = {
  workoutType: string | null;
};

就加个问号?到可选字段。

interface Employee{
   id: number;
   name: string;
   salary?: number;
}