html-to-pdfmake

html-to-pdfmake

pdfmake permits to easily create a PDF with JavaScript, but the support of HTML was missing. After reviewing issue #205 I decided to create a module to handle this feature.

Online Demo

You can find the online demo at https://aymkdn.github.io/html-to-pdfmake/index.html

Install

npm install html-to-pdfmake

How to use

This module will convert some basic and valid HTML code to its equivalent in pdfmake.

var pdfMake = require("pdfmake/build/pdfmake");
var pdfFonts = require("pdfmake/build/vfs_fonts");
pdfMake.vfs = pdfFonts.pdfMake.vfs;
var htmlToPdfMake = require("html-to-pdfmake");
// or:
// import htmlToPdfMake from "html-to-pdfmake"

var html = htmlToPdfMake(`
  <div>
    <h1>My title</h1>
    <p>
      This is a sentence with a <strong>bold word</strong>, <em>one in italic</em>,
      and <u>one with underline</u>. And finally <a href="https://www.somewhere.com">a link</a>.
    </p>
  </div>
`);

/*
it will return:
{
  stack:[
    {
      text: 'My title',
      fontSize: 24,
      bold: true,
      marginBottom: 5,
      style: ['html-h1']
    },
    {
      text: [
        {
          text: 'This is a sentence with a '
        },
        {
          text: 'bold word',
          bold: true,
          style: ['html-strong']
        },
        {
          text: ', '
        },
        {
          text: 'one in italic',
          italics: true,
          style: ['html-em']
        },
        {
          text: ', and '
        },
        {
          text: 'one with underline',
          decoration: 'underline',
          style: ['html-u']
        },
        {
          text: '. And finally '
        },
        {
          text: 'a link',
          color: 'blue',
          decoration: 'underline',
          link: 'https://www.somewhere.com',
          style: ['html-a']
        },
        {
          text: '.'
        }
      ],
      margin: [0, 5, 0, 10],
      style: ['html-p']
    }
  ],
  style: ['html-div']
}
 */

Documentation

HTML tags supported

The below HTML tags are supported:

• DIV / P / SPAN
• BR
• B / STRONG
• I / EM
• S
• UL / OL / LI
• TABLE / THEAD / TBODY / TFOOTER / TR / TH / TD
• H1 to H6
• IMG

Default styles

I've defined some default styles for the supported element.

For example, using a <STRONG> will display the word in bold. Or, a link will appear in blue with an underline, and so on...

Here is the list of defaults styles:

{
    b: {bold:true},
    strong: {bold:true},
    u: {decoration:'underline'},
    s: {decoration: 'lineThrough'},
    em: {italics:true},
    i: {italics:true},
    h1: {fontSize:24, bold:true, marginBottom:5},
    h2: {fontSize:22, bold:true, marginBottom:5},
    h3: {fontSize:20, bold:true, marginBottom:5},
    h4: {fontSize:18, bold:true, marginBottom:5},
    h5: {fontSize:16, bold:true, marginBottom:5},
    h6: {fontSize:14, bold:true, marginBottom:5},
    a: {color:'blue', decoration:'underline'},
    strike: {decoration: 'lineThrough'},
    p: {margin:[0, 5, 0, 10]},
    ul: {marginBottom:5},
    li: {marginLeft:5},
    table: {marginBottom:5},
    th: {bold:true, fillColor:'#EEEEEE'}
  }

Please, note that the above default styles are stronger than the ones defined in the style classes. Read below how to overwrite them.

Customize style

Each converted element will have an associated style-class called html-tagname.

For example, if you want all <STRONG> tags to be highlighted with a yellow backgroud you can use html-strong in the styles definition:

var html = htmlToPdfMake(`
  <p>
    This sentence has <strong>a highlighted word</strong>, but not only.
  </p>
  `);

var docDefinition = {
  content: [
    html
  ],
  styles:{
    'html-strong':{
      background:'yellow' // it will add a yellow background to all <STRONG> elements
    }
  }
};

var pdfDocGenerator = pdfMake.createPdf(docDefinition);

CSS class and style

The class and styles for the elements will also be added.

var html = htmlToPdfMake(`
  <p>
    This sentence has <span style="font-weight:bold" class="red">a bold and red word</span>.
  </p>
  `);

/*
It returns:
{
  text: [
    {
      text: 'This sentence has '
    },
    {
      text: 'a bold and red word',
      style: ['red', 'html-span'], // 'red' added because of `class="red"`
      bold: true // added because of `style="font-weight:bold"`
    },
    {
      text: '.'
    }
  ],
  margin: [0, 5, 0, 10],
  style: ['html-p']
}
*/

var docDefinition = {
 content: [
   html
 ],
 styles:{
   red:{ // we define the class called "red"
     color:'red'
   }
 }
};

var pdfDocGenerator = pdfMake.createPdf(docDefinition);

Please, note that the default styles are stronger than the ones defined in the style classes. For example, if you define a class html-a to change all links in purple, then it won't work because the default styles will overwrite it:

var docDefinition = {
 content: [
   html
 ],
 styles:{
   'html-a':{
     color:'purple' // it won't work: all links will remain 'blue'
   }
 }
};

To make it work, you have to either delete the default styles, or change it with a new value. Starting v1.1.0, an option parameter is available as a second parameter.

Example: you want <li> to not have a margin-left, and <a> to be 'purple' and without 'underline' style:

var html = htmlToPdfMake('<ul><li>this is <a href="...">a link</a></li><li>another item</li><li class="with-margin">3rd item with a margin</li></ul>', {
  defaultStyles:{ // change the default styles
    a:{ // for <A>
      color:'purple', // all links should be 'purple'
      decoration:'' // remove underline
    },
    li:'' // remove all default styles for <LI>
  }
});

var docDefinition = {
 content: [
   html
 ],
 styles:{
   'with-margin':{
     marginLeft: 30 // apply a margin with the specific class is used
   }
 }
};

<img>

The <img> tag is supported, however the src attribute must already be a base64 encoded content (as describe in the PDFMake documentation).

This is too complex and out of the scope of this module to find and convert the image source to a base64 format. You can check this Stackoverflow question to know the different ways to get a base64 encoded content from an image.

Examples

You can find more examples in example.js which will create example.pdf:

node example.js

Donate

You can support my work by making a donation. Thank you!