npm i html2canvas
npm i jspdf

import html2canvas from 'html2canvas';
import jsPDF from 'jspdf'
export const htmlToPDF = async (htmlId: string, title: string = "報(bào)表", bgColor = "#fff") => {
    let pdfDom: HTMLElement | null = document.getElementById(htmlId) as HTMLElement
    pdfDom.style.padding = '0 10px !important'
    const A4Width = 595.28;
    const A4Height = 841.89;
    let canvas = await html2canvas(pdfDom, {
        scale: 2,
        useCORS: true,
        backgroundColor: bgColor,
    });
    let pageHeight = (canvas.width / A4Width) * A4Height;
    let leftHeight = canvas.height;
    let position = 0;
    let imgWidth = A4Width;
    let imgHeight = (A4Width / canvas.width) * canvas.height;
    /*
     根據(jù)自身業(yè)務(wù)需求  是否在此處鍵入下方水印代碼
    */
    let pageData = canvas.toDataURL("image/jpeg", 1.0);
    let PDF = new jsPDF("p", 'pt', 'a4');
    if (leftHeight < pageHeight) {
        PDF.addImage(pageData, "JPEG", 0, 0, imgWidth, imgHeight);
    } else {
        while (leftHeight > 0) {
            PDF.addImage(pageData, "JPEG", 0, position, imgWidth, imgHeight);
            leftHeight -= pageHeight;
            position -= A4Height;
            if (leftHeight > 0) PDF.addPage();
        }
    }
    PDF.save(title + ".pdf");
}

const ctx: any = canvas.getContext('2d');
ctx.textAlign = 'center';
ctx.textBaseline = 'middle';
ctx.rotate((20 * Math.PI) / 180);
ctx.font = '20px Microsoft Yahei';
ctx.fillStyle = 'rgba(184, 184, 184, 0.8)';
for (let i = canvas.width * -1; i < canvas.width; i += 240) {
    for (let j = canvas.height * -1; j < canvas.height; j += 200) {
        // 填充文字，x 間距, y 間距
        ctx.fillText('水印名', i, j);
    }
}

import { htmlToPDF } from '@/utils/html2pdf'

<div id="test-id" style="padding: 20px 0;">
    <div style="background: #000;width: 100px;height: 100px;margin: auto;"></div>
    <p>test</p>
    <p>test</p>
    <p>test</p>
    <p>test</p>
    <p>test</p>
    <p>test</p>
    <p>test</p>
</div>
<button @click="() => htmlToPDF('test-id','test pdf')">導(dǎo)出</button>