如何在NestJS(TypeScript)中使用pdfmake库生成PDF？

由于pdfmake官方文档对NestJS环境下的实现说明不完善，这里分享一套在Node 20环境下验证有效的实现方法：

安装依赖 #

首先执行以下命令安装所需包：

npm install pdfmake --save
npm install @types/pdfmake --save-dev

实现代码 #

在NestJS的Service中编写如下代码：

import { Injectable } from '@nestjs/common';
import pdfFonts from 'pdfmake/build/vfs_fonts';
import * as fs from 'fs';
import pdfMake from 'pdfmake/build/pdfmake';
import { TDocumentDefinitions } from 'pdfmake/interfaces';

@Injectable()
export class AppService {
  constructor() {
    // 注册pdfmake所需的字体文件
    (pdfMake as any).vfs = pdfFonts.pdfMake.vfs;
  }

  generatePdf() {
    // 定义PDF文档内容结构
    const dd: TDocumentDefinitions = {
      content: [
        'First paragraph',
        'Another paragraph, this time a little bit longer to make sure, this line will be divided into at least two lines',
        {
          text: 'This paragraph will have a bigger font',
          fontSize: 15,
          color: 'blue',
        },
        {
          columns: [
            {
              text: 'This is a column',
            },
            {
              text: 'Another column',
            },
          ],
        },
        { text: 'Tables', style: 'header' },
        'Official documentation is in progress, this document is just a glimpse of what is possible with pdfmake and its layout engine.',
        {
          text: 'A simple table (no headers, no width specified, no spans, no styling)',
          style: 'subheader',
        },
        'The following table has nothing more than a body array',
        {
          style: 'tableExample',
          table: {
            body: [
              ['Column 1', 'Column 2', 'Column 3'],
              ['One value goes here', 'Another one here', 'OK?'],
            ],
          },
        },
      ],
    };

    // 创建PDF实例并生成文件
    const pdfDoc = pdfMake.createPdf(dd);
    pdfDoc.getBuffer((buffer) => {
      // 确保pdf目录存在，避免写入失败
      if (!fs.existsSync('pdf')) {
        fs.mkdirSync('pdf');
      }
      fs.writeFileSync('pdf/output.pdf', buffer);
      console.log('PDF saved successfully');
    });

    return 'PDF generated successfully!';
  }
}

关键说明 #

• 构造函数中注册字体文件是必要操作，否则会出现字体加载失败的问题
• 示例中通过getBuffer获取PDF的Buffer数据并写入本地文件，你也可以直接将Buffer返回给前端作为下载响应
• pdfmake支持文本、表格、多列布局等多种自定义配置，是一款功能强大的后端PDF生成工具

内容的提问来源于stack exchange，提问作者Jeferson Narvaez