docx-templates

Docx-templates

Template-based docx report creation for both Node and the browser. (See the blog post).

Why?

• Write documents naturally using Word, just adding some commands where needed for dynamic contents
• Express your data needs (queries) in the template itself (QUERY command), in whatever query language you want (e.g. in GraphQL). This is similar to the Relay way™: in Relay, data requirements are declared alongside the React components that need the data
• Execute JavaScript snippets (EXEC command, or ! for short)
• Insert the result of JavaScript snippets in your document (INS, or = for short)
• Embed images, hyperlinks and even HTML dynamically (IMAGE, LINK, HTML). Dynamic images can be great for on-the-fly QR codes, downloading photos straight to your reports, charts… even maps!
• Add loops with FOR/END-FOR commands, with support for table rows, nested loops, and JavaScript processing of elements (filter, sort, etc)
• Include contents conditionally, IF a certain JavaScript expression is truthy
• Define custom aliases for some commands (ALIAS) — useful for writing table templates!
• Run all JavaScript in a separate Node VM for security
• Include literal XML
• Plenty of examples in this repo (with Node, Webpack and Browserify)

Contributions are welcome!

Installation

$ npm install docx-templates

...or using yarn:

$ yarn add docx-templates

Node usage

Here is a (contrived) example, with report data injected directly as an object:

import createReport from 'docx-templates';

createReport({
  template: 'templates/myTemplate.docx',
  output: 'reports/myReport.docx',
  data: {
    name: 'John',
    surname: 'Appleseed',
  },
});

This will create a report based on the input data at the specified path. Some notes:

• All paths are relative to process.cwd()
• If the output location is omitted, a report will be generated in the same folder as the template

You can also provide a sync or Promise-returning callback function (query resolver) instead of a data object:

createReport({
  template: 'templates/myTemplate.docx',
  output: 'reports/myReport.docx',
  data: query => graphqlServer.execute(query),
});

Your resolver callback will receive the query embedded in the template (in a QUERY command) as an argument.

You can also output to a buffer:

const buffer = createReport({
  output: 'buffer',
  template: 'templates/myTemplate.docx',
  data: { ... },
});

...and pass a buffer as an input template:

const template = // read from db, http etc as Buffer
const buffer = createReport({
  output: 'buffer',
  template,
  data: { ... },
});

Other options (with defaults):

createReport({
  // ...
  additionalJsContext: {
    // all of these will be available to JS snippets in your template commands (see below)
    foo: 'bar',
    qrCode: async url => {
      /* build QR and return image data */
    },
  },
  cmdDelimiter: '+++',
  literalXmlDelimiter: '||',
  processLineBreaks: true,
  noSandbox: false,
  vm2Sandbox: false, // note that vm2 sandbox is safer than Node's
});

Check out the Node examples folder.

Browser usage

You can use docx-templates in the browser (yay!). Make sure, however, to shim the vm2 package (due to this) in your Browserify config (example) or webpack config (example).

Instead of providing docx-templates with the template's path, pass the template contents as a buffer. For example, get a File object with:

<input type="file">

Then read this file in an ArrayBuffer, feed it to docx-templates, and download the result:

import createReport from 'docx-templates';

const onTemplateChosen = async () => {
  const template = await readFileIntoArrayBuffer(myFile);
  const report = await createReport({
    template,
    data: { name: 'John', surname: 'Appleseed' },
  });
  saveDataToFile(
    report,
    'report.docx',
    'application/vnd.openxmlformats-officedocument.wordprocessingml.document'
  );
};

// Load the user-provided file into an ArrayBuffer
const readFileIntoArrayBuffer = fd =>
  new Promise((resolve, reject) => {
    const reader = new FileReader();
    reader.onerror = reject;
    reader.onload = () => {
      resolve(reader.result);
    };
    reader.readAsArrayBuffer(fd);
  });

You can find an example implementation of saveDataToFile() in the Webpack example.

With the default configuration, browser usage can become slow with complex templates due to the usage of JS sandboxes for security reasons. If the templates you'll be using with docx-templates can be trusted 100%, you can disable the security sandboxes by configuring noSandbox: true. Beware of arbitrary code injection risks:

createReport({
  // ...
  // USE ONLY IN THE BROWSER, AND WITH TRUSTED TEMPLATES
  noSandbox: true, // WARNING: INSECURE
});

Check out the examples using Webpack and using Browserify.

Writing templates

You can find several template examples in this repo:

• SWAPI, a good example of what you can achieve embedding a template (GraphQL in this case) in your report, including a simple script for report generation. Uses the freak-ish online Star Wars GraphQL API.
• Dynamic images: with examples of images that are dynamically downloaded or created. Check out the images-many-tiles example for a taste of this powerful feature.
• Browser-based examples using Webpack and using Browserify.

Currently supported commands are defined below.

QUERY

You can use GraphQL, SQL, whatever you want: the query will be passed unchanged to your data query resolver.

+++QUERY
query getData($projectId: Int!) {
  project(id: $projectId) {
    name
    details { year }
    people(sortedBy: "name") { name }
  }
}
+++

For the following sections (except where noted), we assume the following dataset:

const data = {
  project: {
    name: 'docx-templates',
    details: { year: '2016' },
    people: [{ name: 'John', since: 2015 }, { name: 'Robert', since: 2010 }],
  },
};

INS (=)

Inserts the result of a given JavaScript snippet:

+++INS project.name+++ (+++INS project.details.year+++)
or...
+++INS `${project.name} (${$details.year})`+++

Note that the last evaluated expression is inserted into the document, so you can include more complex code if you wish:

+++INS
const a = Math.random();
const b = Math.round((a - 0.5) * 20);
`A number between -10 and 10: ${b}.`
+++

You can also use this shorthand notation:

+++= project.name+++ (+++= project.details.year+++)
+++= `${project.name} (${$details.year})`+++

You can also access functions in the additionalJsContext parameter to createReport(), which may even return a Promise. The resolved value of the Promise will be inserted in the document.

Use JavaScript's ternary operator to implement an if-else structure:

+++= $details.year != null ? `(${$details.year})` : ''+++

EXEC (!)

Executes a given JavaScript snippet, just like INS or =, but doesn't insert anything in the document. You can use EXEC, for example, to define functions or constants before using them elsewhere in your template.

+++EXEC
const myFun = () => Math.random();
const MY_CONSTANT = 3;
+++

+++! const ANOTHER_CONSTANT = 5; +++

IMAGE

Includes an image with the data resulting from evaluating a JavaScript snippet:

+++IMAGE qrCode(project.url)+++

In this case, we use a function from additionalJsContext object passed to createReport() that looks like this:

  additionalJsContext: {
    qrCode: url => {
      const dataUrl = createQrImage(url, { size: 500 });
      const data = dataUrl.slice('data:image/gif;base64,'.length);
      return { width: 6, height: 6, data, extension: '.gif' };
    },
  }

The JS snippet must return an image object or a Promise of an image object, containing:

• width in cm
• height in cm
• path [optional] (in Node only): path to the image to be embedded (absolute or relative to the current working directory)
• data [optional]: either an ArrayBuffer or a base64 string with the image data
• extension [optional]: e.g. .png

Either specify the path or data + extension.

LINK

Includes a hyperlink with the data resulting from evaluating a JavaScript snippet:

+++LINK ({ url: project.url, label: project.name })+++

If the label is not specified, the URL is used as a label.

HTML

Takes the HTML resulting from evaluating a JavaScript snippet and converts it to Word contents (using altchunk):

+++HTML `
<body>
  <h1>${$film.title}</h1>
  <h3>${$film.releaseDate.slice(0, 4)}</h3>
  <p>
    <strong style="color: red;">This paragraph should be red and strong</strong>
  </p>
</body>
`+++

FOR and END-FOR

Loop over a group of elements (resulting from the evaluation of a JavaScript expression):

+++FOR person IN project.people+++
+++INS $person.name+++ (since +++INS $person.since+++)
+++END-FOR person+++

Since JavaScript expressions are supported, you can for example filter the loop domain:

+++FOR person IN project.people.filter(person => person.since > 2013)+++
...

FOR loops also work over table rows:

----------------------------------------------------------
| Name                         | Since                   |
----------------------------------------------------------
| +++FOR person IN             |                         |
| project.people+++            |                         |
----------------------------------------------------------
| +++INS $person.name+++       | +++INS $person.since+++ |
----------------------------------------------------------
| +++END-FOR person+++         |                         |
----------------------------------------------------------

Finally, you can nest loops (this example assumes a different data set):

+++FOR company IN companies+++
+++INS $company.name+++
+++FOR person IN $company.people+++
* +++INS $person.firstName+++
+++FOR project IN $person.projects+++
    - +++INS $project.name+++
+++END-FOR project+++
+++END-FOR person+++

+++END-FOR company+++

IF and END-IF

Include contents conditionally (depending on the evaluation of a JavaScript expression):

+++IF person.name === 'Guillermo'+++
+++= person.fullName +++
+++END-IF+++

Similarly to the FOR command, it also works over table rows. You can also nest IF commands and mix & match IF and FOR commands. In fact, for the technically inclined: the IF command is implemented as a FOR command with 1 or 0 iterations, depending on the expression value.

ALIAS (and alias resolution with *)

Define a name for a complete command (especially useful for formatting tables):

+++ALIAS name INS $person.name+++
+++ALIAS since INS $person.since+++

----------------------------------------------------------
| Name                         | Since                   |
----------------------------------------------------------
| +++FOR person IN             |                         |
| project.people+++            |                         |
----------------------------------------------------------
| +++*name+++                  | +++*since+++            |
----------------------------------------------------------
| +++END-FOR person+++         |                         |
----------------------------------------------------------

Replacing template images

Note: this feature is deprecated as of v2.4.0 and may be removed in future releases. Please use the IMAGE command instead.

You can replace images in your template by specifying the replaceImages option when you create your report:

createReport({
  // ...
  replaceImages: {
    'image1.png': '/absolute/path/to/newImage1.png',
    'image3.png': '/absolute/path/to/newImage3.png',
  },
});

If you prefer, you can pass in a base64 string with the contents (if you're using docx-templates in the browser, this is the only supported way):

createReport({
  // ...
  replaceImagesBase64: true,
  replaceImages: {
    'image1.png': '<base64 data>',
    'image3.png': '<base64 data>',
  },
});

You can determine the original image file names by inspecting your template: unzip your .docx file (you may need to duplicate it and change its extension to .zip before), navigate to the word/media folder inside and find the image you want to replace:

├─word
| ├─media
| | ├─image1.png
| | ├─image2.png
| | ├─image3.png
| | ├─...

Changelog

Similar projects

• docxtemplater (believe it or not, I just discovered this very similarly-named project after brushing up my old CS code for docx-templates and publishing it for the first time!). It provides lots of goodies, but doesn't allow (AFAIK) embedding queries or JS snippets.

• docx and similar ones - generate docx files from scratch, programmatically. Drawbacks of this approach: they typically do not support all Word features, and producing a complex document can be challenging.

License (MIT)

Copyright (c) Guillermo Grau Panea 2016-now

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Changelog

2.8.0 (2018-11-19)

• Accept Buffer in template and 'buffer' in output.