打字稿類如何指定該元素可以是可選的

Question

假設有這個接口：Employee.model.ts：

interface EmployeeInterface{
    name: string;
    salary?: number;
    date: Date;
}

我知道我該怎么做：

export class Employee implements EmployeeInterface{
    public name: string;
    public salary: number;
    public date: Date;
}

我的問題是我如何在構造函數中指定薪水參數可以或不可以？

Answer 1

您可以將字段定義為參數構造函數（通過向參數添加可見性修飾符）並將適當的字段和參數標記為可選（但您需要將其放在參數列表的末尾）：

interface ObjectToSellInterface{
  name: string;
  salary?: number;
  date: Date;
}
export class ObjectToSell implements ObjectToSellInterface{
  public constructor(
    public name: string,
    public date: Date, 
    public salary?: number){ }
}

上面的代碼等價於：

export class ObjectToSell implements ObjectToSellInterface{

  public name: string;
  public date: Date;
  public salary?: number;

  public constructor(
    name: string,
    date: Date, 
    salary?: number){ 
      this.date = date;
      this.name = name;
      this.salary = salary;
    }
}