---
robots: noindex, nofollow
tags: refactoring
---

# Remove Setting Method

> 練習用的 [REPL](https://repl.it/@yaosiang/RemoveSettingMethod)

class Person {
    get name()    {return this._name;}
    set name(arg) {this._name = arg;} // setter
    get id()      {return this._id;}
    set id(arg)   {this._id = arg;}   // setter
}

呼叫端可以會直接指定 ID。

const martin = new Person();
martin.name = "martin";
martin.id = "1234"; // 使用了 setter

但 ID 應該在物件建立後，就不允許修改。

class Person {
    constructor(id) {
        this.id = id;
    }
    get name()    {return this._name;}
    set name(arg) {this._name = arg;}
    get id()    {return this._id;}
    set id(arg) {this._id = arg;}
}

當可以使用建構子來傳遞 ID 後。

const martin = new Person("1234");
martin.name = "martin";
martin.id = "1234";

ID 的 setter 就可以刪除了。

class Person {
    constructor(id) {
        this.id = id;
    }
    get name()    {return this._name;}
    set name(arg) {this._name = arg;}
    get id()    {return this._id;}
    // set id(arg) {this._id = arg;}    // 移除 setter
}