javascript - 是否可以在类中的 this.var 上设置 Object.defineProperty()

Question

所以我创建了一个具有以下构造函数和方法的 Complex 类

class Komplex {
  constructor(real, imag) {
    if (real === undefined && imag === undefined) {
      real = 0
      imag = 0
      this.real = real
      this.imag = imag
    } else if (imag === undefined) {
      this.real = real
      this.imag = 0
    } else if (typeof real === "number" && typeof imag === "number") {
      this.real = real
      this.imag = imag
    } else {
      real = 0
      imag = 0
      this.real = real
      this.imag = imag
    }
  }
}

所以我的问题是如何使用 Object.defineProperty() 使“this.real”和“this.imag”不可写； ？

Answer 1

将 Object.defineProperties(一次定义多个属性)与 this 一起使用。 writable 属性定义目标对象中定义的属性是否只可读，默认为false

另请参阅 MDN 上的文档:

writable

true if and only if the value associated with the property may be changed with an assignment operator.

Defaults to false.

class Komplex {
  constructor(real, imag) {
    if (real === undefined && imag === undefined) {
      real = 0
      imag = 0
    } else if (imag === undefined) {
      imag = 0
    } else if (typeof real !== "number" || typeof imag !== "number") {
      real = 0
      imag = 0
    }

    Object.defineProperties(this, {
      real: {
        value: real
      },
      imag: {
        value: imag
      }
    });
  }
}


(function() {
  'use strict';

  let val = new Komplex(1, 2);
  val.real = 5;
})();