Node.js邮件内容构建优化咨询：替代硬编码实现方案

问题背景 #

我基于Node.js开发业务功能，需根据业务执行结果向支持团队及用户发送邮件，当前采用硬拼接HTML标签的方式构建邮件内容，代码如下：

let emailStartTags = "<html><body><p>Hi Team,</p><p>";
const emailEndTags = "</p><p>Thanks,<br>ABC Support</p></body></html>"  
const Subject = `DEV Order No 1234`
let emailContent="";
emailContent+=emailStartTags;
const s3FilesList = await this.getFilesFromS3Directory(directoryName)
emailContent+="<p>S3 files are ${s3FilesList}<p>"
emailContent+=emailEndTags

await this.sendEmail(emailContent,Subject,From,To);

请问是否有更优的邮件内容构建方式替代上述硬编码实现？比如使用带getter/setter的邮件类，若可行请提供参考方案。

方案一：模板引擎（推荐） #

硬拼接HTML的核心痛点是维护成本高、易出现标签语法错误，模板引擎能实现内容与结构分离，常用的有EJS、Handlebars等，以EJS为例：

1. 安装依赖

npm install ejs

2. 创建独立的邮件模板文件（如order-notification.ejs）

<html>
<body>
  <p>Hi Team,</p>
  <p>S3 files are <%= s3FilesList %></p>
  <p>Thanks,<br>ABC Support</p>
</body>
</html>

3. 在业务代码中渲染模板

const ejs = require('ejs');
const fs = require('fs').promises;

async function renderEmailTemplate(data) {
  const templateContent = await fs.readFile('./order-notification.ejs', 'utf8');
  return ejs.render(templateContent, data);
}

// 业务逻辑中调用
const subject = `DEV Order No 1234`;
const s3FilesList = await this.getFilesFromS3Directory(directoryName);
const emailContent = await renderEmailTemplate({ s3FilesList });

await this.sendEmail(emailContent, subject, From, To);

方案二：封装带getter/setter的邮件类 #

如果需要更强的封装性和数据校验能力，可以创建邮件构建类，把动态数据、模板结构统一管理：

class OrderEmailBuilder {
  constructor() {
    this._recipient = 'Team';
    this._s3Files = [];
    this._orderNumber = '';
  }

  // 收件人称呼的getter/setter
  set recipient(type) {
    if (typeof type === 'string' && type.trim()) {
      this._recipient = type.trim();
    } else {
      throw new Error('Recipient must be a valid string');
    }
  }
  get recipient() {
    return this._recipient;
  }

  // S3文件列表的getter/setter
  set s3Files(files) {
    if (Array.isArray(files)) {
      this._s3Files = files;
    } else {
      throw new Error('S3 files must be an array');
    }
  }
  get s3Files() {
    return this._s3Files;
  }

  // 订单号的getter/setter
  set orderNumber(num) {
    if (typeof num === 'string' && num.trim()) {
      this._orderNumber = num.trim();
    } else {
      throw new Error('Order number must be a valid string');
    }
  }
  get orderNumber() {
    return this._orderNumber;
  }

  // 自动生成邮件主题
  get subject() {
    return `DEV Order No ${this._orderNumber}`;
  }

  // 构建最终HTML内容
  buildHtmlContent() {
    const filesListHtml = this._s3Files.map(file => `<li>${file}</li>`).join('');
    return `
      <html>
      <body>
        <p>Hi ${this._recipient},</p>
        <p>S3 files are:</p>
        <ul>${filesListHtml}</ul>
        <p>Thanks,<br>ABC Support</p>
      </body>
      </html>
    `.trim();
  }
}

// 业务代码中使用
const emailBuilder = new OrderEmailBuilder();
emailBuilder.orderNumber = '1234';
emailBuilder.s3Files = await this.getFilesFromS3Directory(directoryName);

const emailContent = emailBuilder.buildHtmlContent();
const subject = emailBuilder.subject;

await this.sendEmail(emailContent, subject, From, To);

方案对比 #

• 模板引擎：适合内容复杂、需要频繁修改邮件结构的场景，非开发人员也能编辑模板，维护成本低；
• 邮件类：适合逻辑固定、对数据格式有严格要求的场景，封装性强，能统一控制数据校验和内容生成逻辑。

内容的提问来源于stack exchange，提问作者Pavan Kumar