Question

我不知道如何在构造函数中使用 setter，我想在设置字段之前验证它们，并且我想通过构造函数来做到这一点，所以这就是我想要做的：

class Person {
  private _name: string;

  constructor(newName: string) {
    // this.name(..) gives error, This expression is not callable. Type 'String' has no call signatures.
    this._name = this.name(newName);
  }

  get name(): string {
    return this._name;
  }

  set name(newName: string) {
    if (newName.length > 2 && newName.length < 10) {
      this._name = newName;
    } else {
      throw new RangeError("Must be between 2 and 10 characters of length");
    }
  }
}

这样我就可以简单地做：

const George = new Person("George")

Answer 1

不应显式调用Setter（和getter）。当您为属性赋值时（即执行 this.name = value; 时），setter 会自动调用：

class Person {
  private _name = '';

  constructor(newName: string) {
    this.name = newName
  }

  get name(): string {
    return this._name;
  }

  set name(newName: string) {
    if (newName.length > 2 && newName.length < 10) {
      this._name = newName;
    } else {
      throw new RangeError("Must be between 2 and 10 characters of length");
    }
  }
}

console.log(new Person('George').name);

如何在构造函数中使用setter？

1 个答案: