Welcome to Code Forum!

Join a community that supports you and your coding journey from day one. We strive to be a friendly, supportive community that empowers everyone to be better developers. By registering with us, you'll be able to discuss, share and private message with other members of our community.

SignUp Now!
  • Guest, before posting your code please take these rules into consideration:
    • It is required to use our BBCode feature to display your code. While within the editor click < / > or >_ and place your code within the BB Code prompt. This helps others with finding a solution by making it easier to read and easier to copy.
    • You can also use markdown to share your code. When using markdown your code will be automatically converted to BBCode. For help with markdown check out the markdown guide.
    • Don't share a wall of code. All we want is the problem area, the code related to your issue.

    GIF shows where to locate </> in the thread and or post editor toolbar.
    To learn more about how to use our BBCode feature, review our "How to post your code into threads" here.

    Thank you, Code Forum.

JavaScript [JavaScript/Node.js] use class to define enum types

xkkui

New Coder
Hi! Every body, I found a lot of articles, how to define enum in JavaScript/Node.js.
Most of the answer that is usage closure function.
But I found the article that is usage class.
The following code:
JavaScript:
"use strict";

class GenderTypeEnum {
    static SECRECY = new GenderTypeEnum(0, "保密");
    static MALE = new GenderTypeEnum(1, "男");
    static FEMALE = new GenderTypeEnum(2, "女");

    constructor (code, name) {
        this.code = code;
        this.name = name;
    }
}

module.exports = GenderTypeEnum;

I try using the code. But I discover that static field or field of instance can be changed on outside of module.
e.g.:
Code:
const GenderTypeEnum = require("./GenderTypeEnum");
console.log(GenderTypeEnum.MALE.code); /// 1

GenderTypeEnum.MALE.code = 4;
console.log(GenderTypeEnum.MALE.code); /// 4

console.log(GenderTypeEnum.FEMALE); /// GenderTypeEnum { code: 2, name: '女' }

GenderTypeEnum.FEMALE = "female";
console.log(GenderTypeEnum.FEMALE); /// female

Refer: https://www.sohamkamani.com/javascript/enums/
 
Hi! Every body, I found a lot of articles, how to define enum in JavaScript/Node.js.
Most of the answer that is usage closure function.
But I found the article that is usage class.
The following code:
JavaScript:
"use strict";

class GenderTypeEnum {
    static SECRECY = new GenderTypeEnum(0, "保密");
    static MALE = new GenderTypeEnum(1, "男");
    static FEMALE = new GenderTypeEnum(2, "女");

    constructor (code, name) {
        this.code = code;
        this.name = name;
    }
}

module.exports = GenderTypeEnum;

I try using the code. But I discover that static field or field of instance can be changed on outside of module.
e.g.:
JavaScript:
const GenderTypeEnum = require("./GenderTypeEnum");
console.log(GenderTypeEnum.MALE.code); /// 1

GenderTypeEnum.MALE.code = 4;
console.log(GenderTypeEnum.MALE.code); /// 4

console.log(GenderTypeEnum.FEMALE); /// GenderTypeEnum { code: 2, name: '女' }

GenderTypeEnum.FEMALE = "female";
console.log(GenderTypeEnum.FEMALE); /// female

And then i modified, the following:
JavaScript:
"use strict";

class GenderTypeEnum {
    static SECRECY = new GenderTypeEnum(0, "保密");
    static MALE = new GenderTypeEnum(1, "男");
    static FEMALE = new GenderTypeEnum(2, "女");

    constructor (code, name) {
        this.code = code;
        this.name = name;

        Object.freeze(this); /// freeze object, fields of code and name is forbade changing
    }
}

/// freeze class, static field of GenderTypeEnum class is forbade changing
module.exports = Object.freeze(GenderTypeEnum);

Regardless of compatibility, Bewteen closure function and the above code which is better.

Please forgive me for my poor English.
Refer: https://www.sohamkamani.com/javascript/enums/
 

Buy us a coffee!

Buy me a coffee.
Back
Top Bottom