easy-template-x

Generate docx documents from templates, in Node or in the browser.

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• Node Example
• Browser Example
• Live Demo
• Plugins
  • Text plugin
  • Loop plugin
    • Conditions
    • Nested Conditions
    • Controlling loop behavior
  • Image plugin
    • Text tag replacement
    • Image placeholder replacement
  • Link plugin
  • Chart plugin
  • Raw xml plugin
  • Writing custom plugins
• Listing tags
• Scope resolution
• Extensions
  • Community Extensions
    • Data Binding Extension
• Template handler options
  • Custom tag delimiters
  • Advanced syntax and custom resolvers
• Supported Binary Formats
• Internal API
• Philosophy
• Changelog

Node Example

import * as fs from 'fs';
import { TemplateHandler } from 'easy-template-x';

// 1. read template file
const templateFile = fs.readFileSync('myTemplate.docx');

// 2. process the template
const data = {
    posts: [
        { author: 'Alon Bar', text: 'Very important\ntext here!' },
        { author: 'Alon Bar', text: 'Forgot to mention that...' }
    ]
};

const handler = new TemplateHandler();
const doc = await handler.process(templateFile, data);

// 3. save output
fs.writeFileSync('myTemplate - output.docx', doc);

Input:

Output:

Browser Example

The following example produces the same output while running in the browser. Notice that the actual template processing (step 2) is exactly the same as in the previous Node example.

import { TemplateHandler } from 'easy-template-x';

// 1. read template file

// (in this example we're loading the template by performing  
//  an AJAX call using the fetch API, another common way to  
//  get your hand on a Blob is to use an HTML File Input)
const response = await fetch('http://somewhere.com/myTemplate.docx');
const templateFile = await response.blob();

// 2. process the template
const data = {
    posts: [
        { author: 'Alon Bar', text: 'Very important\ntext here!' },
        { author: 'Alon Bar', text: 'Forgot to mention that...' }
    ]
};

const handler = new TemplateHandler();
const doc = await handler.process(templateFile, data);

// 3. save output
saveFile('myTemplate - output.docx', doc);

function saveFile(filename, blob) {

    // see: https://stackoverflow.com/questions/19327749/javascript-blob-filename-without-link

    // get downloadable url from the blob
    const blobUrl = URL.createObjectURL(blob);

    // create temp link element
    let link = document.createElement("a");
    link.download = filename;
    link.href = blobUrl;

    // use the link to invoke a download
    document.body.appendChild(link);
    link.click();

    // remove the link
    setTimeout(() => {
        link.remove();
        window.URL.revokeObjectURL(blobUrl);
        link = null;
    }, 0);
}

Live Demo

Checkout this live demo on CodeSandbox 😎

Plugins

easy-template-x uses a plugin model to support it's various template manipulation capabilities. There are some built-in plugins and you can also write your own custom plugins if required.

These are the plugins that comes bundled with easy-template-x:

• Text plugin - For simple text replacement.
• Loop plugin - For iterating text, table rows, table columns and list rows and for simple conditions.
• Image plugin - For embedding images.
• Link plugin - For hyperlinks creation.
• Chart plugin - For handling charts.
• Raw xml plugin - For custom xml insertion.

Text plugin

The most basic plugin. Replaces a single tag with custom text. Preserves the original text style.

Input template:

Input data:

{
    "First Tag": "Quis et ducimus voluptatum\nipsam id.",
    "Second Tag": "Dolorem sit voluptas magni dolorem molestias."
}

Output document:

Loop plugin

Iterates text, table rows, table columns and lists.
Requires an opening tag that starts with # and a closing tag that starts with / (configurable).

Note: The closing tag does not need to have the same name as the opening tag, or a name at all. This will work {#loop}{/loop}, but also this {#loop}{/} and even this {#loop}{/something else}.

Input template:

Input data:

{
    "Beers": [
        { "Brand": "Carlsberg", "Price": 1 },
        { "Brand": "Leaf Blonde", "Price": 2 },
        { "Brand": "Weihenstephan", "Price": 1.5 }
    ]
}

Output document:

Conditions

You can render content conditionally depending on a boolean value using the same syntax used for loops.

The example below shows two lines being rendered, each with different content depending on the truthy value.

Input template:

Input data:

{
    lines: [
        { visible: true },
        { invisible: true }
    ]
}

Output document:

Nested Conditions

Nested conditions are also supported, so you can nest other tags including loop tags and even other conditions in them. When doing so remember to format your data accordingly. See the example below for clarification:

Input template:

Input data:

Notice how even though name and members are nested in the template under the show condition their values are adjacent to it in the input data.

{
    "teams": [
        {
            show: true,
            name: "A-Team",
            members: [
                { name: "Hannibal" },
                { name: "Face" },
                { name: "Murdock" },
                { name: "Baracus" },
            ]
        },
        {
            show: false,
            name: "B-Team",
            members: [
                { name: "Alice" },
                { name: "Bob" },
                { name: "Charlie" },
                { name: "Dave" },
            ]
        }
    ],
}

Output document:

If you are looking for a yet more powerful conditional syntax see the alternative syntax section.

Controlling loop behavior

The loop plugin uses some heuristics to determine the right behavior in each case (i.e. when to loop over rows, columns, paragraphs, etc.). You can control this behavior explicitly through the loopOver option as explain below.

Default behavior

The default heuristics are as follows:

1. If both loop tags are inside the same table cell - the plugin assumes you want to repeat the cell content, not the row or column.
2. If both loop tags are in the same column - the plugin will repeat the column.
3. If both loop tags are inside a table - the plugin will repeat the relevant table rows.
4. If both loop tags are in a list - the plugin will repeat the relevant list items.
5. Otherwise - the plugin will use a naive approach for repeating the content in between the loop tags.

Changing the default

To use a different behavior than the default one you can use the loopOver option. Supported values are: row, column and content.

Note: This option controls conditions too.

For instance, given this data:

{
    students: [
        { name: "Alice" },
        { name: "Bob" }
    ]
}

You can use this syntax:

Or this syntax:

Or this syntax:

The first will produce this document:

The second will produce this document:

And the third will produce this document:

Image plugin

Embed images into the document.
The image plugin supports two modes:

1. Text tag replacement
2. Image placeholder replacement

Text tag replacement

Insert inline images by placing tags in the document body.

Input template example:

Image placeholder replacement

Replace existing placeholder images while preserving their size, position, and styling.

Note: You can use any image you want as the placeholder.

Input template example:

To let easy-template-x know you want to replace the placeholder image, insert a tag in it's alt text:

Data and output

The data and resulting output are the same for both modes.

Input data:

{
    "Kung Fu Hero": {
        _type: "image",
        source: fs.readFileSync("hero.png"),
        format: MimeType.Png,
        width: 200, // Required for text tags, optional for placeholders
        height: 200, // Required for text tags, optional for placeholders
        altText: "Kung Fu Hero", // Optional
        transparencyPercent: 80 // Optional
    }
}

Output document:

Link plugin

Inserts hyperlinks into the document.
Like text tags link tags also preserve their original style.

Input template:

Input data:

{
    "easy": {
        _type: 'link',
        text: 'super easy',  // Optional - if not specified the `target` property will be used
        target: 'https://github.com/alonrbar/easy-template-x'
    }
}

Output document:

Chart plugin

To use charts in templates, put a placeholder chart and place a tag in its title, like so:

Generally speaking, the charts preserve their original settings and style with some configurations also available through the input json data.

easy-template-x try to keep the same terminology used by MS Word. Therefore, while the exact input data schema depends on the chart type, the main terms are common to most:

• Categories are the values of the X axis.
• Series are the values of the Y axis.

Take a look at the examples below to get a better understanding of how chart tags behave.

Line, bar & column charts

Line, bar & column charts all uses the same input data format.

The example below shows 4 charts in the same template: Line chart, Column chart, Bar chart and Stacked Column chart. In this example all of the charts use the same input data (the MyChart tag data) but you can of course use a different tag for each chart.

Notice how the end result ignores the placeholder data and matches our input data instead.

Note that you are not limited to use the same number of categories or series as the placeholder chart. This specific example uses less series than the placeholder (2 instead of 3) but you can just as easily add more series or change the number of categories.

Input template:

Input data:

{
    MyChart: {
        _type: "chart",
        title: "Easy Chart", // Optional
        categories: {
            names: ["Q1", "Q2", "Q3", "Q4"]
        },
        series: [
            { 
                name: "Earnings",  // Optional
                color: "#34d399", // Optional
                values: [100, 210, 150, 170] 
            },
            { 
                name: "Expenses",
                color: "#f87171",
                values: [170, 165, 169, 155] 
            },
        ],
    }
}

Output document:

Pie & doughnut charts

Pie & doughnut uses the same input data format as line, bar and column chart, except they expect a single series.

The example below shows 4 charts in the same template: 2 pie charts and 2 doughnut charts, each with a different style.

Input template:

Input data:

{
    Chart1: {
        _type: "chart",
        title: "Easy Chart", // Optional
        categories: {
            names: ["Q1", "Q2", "Q3", "Q4"]
        },
        series: [
            { values: [100, 210, 150, 170] },
        ],
    }
}

Output document:

Scatter chart

Scatter chart do not have a categories property. Instead, each of their values requires an x and a y properties.

Input template:

Input data:

{
    scatter: {
        _type: "chart",
        title: "Easy Scatter Chart", // Optional
        series: [
            { 
                name: "Earnings", // Optional
                color: "#34d399", // Optional
                values: [
                    { x: 1, y: 310 },
                    { x: 3, y: 450 },
                    { x: 4, y: 200 },
                    { x: 6, y: 200 },
                ],
            },
            { 
                name: "Expenses",
                color: "#f87171",
                values: [
                    { x: 1, y: 410 },
                    { x: 2, y: 450 },
                    { x: 3, y: 200 },
                    { x: 5, y: 350 },
                ],
            },
        ],
    }
}

Output document:

Bubble chart

Bubble charts are very similar to scatter charts but they have an additional size property (notice the placeholder chart should be a bubble chart, not a scatter chart).

Input template:

Input data:

{
    bubble: {
        _type: "chart",
        title: "Bubble Chart", // Optional
        series: [
            { 
                name: "Earnings", // Optional
                color: "#34d399", // Optional
                values: [
                    { x: 1, y: 10, size: 10 },
                    { x: 2, y: 10, size: 20 },
                    { x: 3, y: 8, size: 40 },
                    { x: 4, y: 8, size: 30 },
                ],
            },
            { 
                name: "Expenses",
                color: "#f87171",
                values: [
                    { x: 1, y: 4, size: 40 },
                    { x: 2, y: 4, size: 20 },
                    { x: 3, y: 3, size: 30 },
                ],
            },
        ],
    }
}

Output document:

Raw xml plugin

Add custom xml into the document to be interpreted by Word.

Tip:
You can add page breaks using this plugin and the following xml markup:
<w:br w:type="page"/>

Input template:

Input data:

{
    "Dont worry be happy": {
        _type: 'rawXml',
        xml: '<w:sym w:font="Wingdings" w:char="F04A"/>',
        replaceParagraph: false,  // Optional - should the plugin replace an entire paragraph or just the tag itself
    }
}

Output document:

Writing your own plugins

To write a plugin inherit from the TemplatePlugin class.
The base class provides two methods you can implement and a set of utilities to make it easier to do the actual xml modification.

To better understand the internal structure of Word documents check out this excellent source.

Example plugin implementation (source):

import { officeMarkup, xml } from "easy-template-x";

/**
 * A plugin that inserts raw xml to the document.
 */
export class RawXmlPlugin extends TemplatePlugin {

    // Declare the unique "content type" this plugin handles
    public readonly contentType = 'rawXml';

    // Plugin logic goes here:
    public simpleTagReplacements(tag: Tag, data: ScopeData): void {
        
        // Get the value to use from the input data.
        const value = data.getScopeData<RawXmlContent>();
        if (value && typeof value.xml === 'string') {

            // Tag.xmlTextNode always reference the actual xml text node.
            // In MS Word each text node is wrapped by a <w:t> node so we retrieve that.
            const wordTextNode = officeMarkup.query.containingTextNode(tag.xmlTextNode);

            // If the input data contains an "xml" string property, parse it and insert 
            // the content next to the placeholder tag.
            const newNode = xml.parser.parse(value.xml);
            xml.modify.insertBefore(newNode, wordTextNode);
        }

        // Remove the placeholder tag.
        officeMarkup.modify.removeTag(tag);
    }
}

The content type that this plugin expects to see is:

export interface RawXmlContent extends PluginContent {
    _type: 'rawXml';
    xml: string;
}

Listing tags

You can get the list of tags in a template by calling the parseTags method as follows:

import { TemplateHandler } from 'easy-template-x';

const templateFile = fs.readFileSync('myTemplate.docx');

const handler = new TemplateHandler();
const tags = await handler.parseTags(templateFile);

Scope resolution

easy-template-x supports tag data scoping. That is, you can reference "shallow" data from within deeper in the hierarchy similarly to how you can reference an outer scope variables from within a function in JavaScript. You can leverage this property to declare "top level" data (your logo and company name or some useful xml snippets like page breaks, etc.) to be used anywhere in the document.

Input template:

(notice that we are using the "Company" tag inside the "Employees" loop)

Input data:

(notice that the "Company" data is declared outside the "Employees" loop, in it's so called "outer scope")

{
    "Company": "Contoso Ltd.",
    "Employees": [
        { "Surname": "Gates", "Given name": "William" },
        { "Surname": "Nadella", "Given name": "Satya" },
    ]
}

Output document:

Extensions

While most document manipulation can be achieved using plugins, there are some cases where a more powerful tool is required. In order to extend the document manipulation process you can specify extensions that will be run before and/or after the standard template processing.

To write an extension inherit from the TemplateExtension class.

By default no extension is loaded. Extensions and the order they run in are specified via the TemplateHandlerOptions.

const handler = new TemplateHandler({
    extensions: {
        afterCompilation: [
            new DataBindingExtension()
        ]
    }
});

Community Extensions

The following extensions were developed by the community.
Want to see your extension here? Submit a pull request or open an issue.

Data Binding Extension

The easy-template-x-data-binding extension supports updating custom XML files inside Word documents.

This allows using easy-template-x to automatically fill Word forms that uses content controls.

Template handler options

You can configure the template handler behavior by passing an options object to it's constructor.

Below is the list of options along with their types and default values:

const handler = new TemplateHandler({

    plugins: createDefaultPlugins(), // TemplatePlugin[]

    defaultContentType: TEXT_CONTENT_TYPE, // string 

    containerContentType: LOOP_CONTENT_TYPE, // string

    delimiters: { // Partial<Delimiters>
        tagStart: "{",
        tagEnd: "}",
        containerTagOpen: "#",
        containerTagClose: "/",
        tagOptionsStart: "[",
        tagOptionsEnd: "]"
    },

    maxXmlDepth: 20,

    extensions: { // ExtensionOptions
        beforeCompilation: undefined, // TemplateExtension[]
        afterCompilation: undefined // TemplateExtension[]
    },

    scopeDataResolver: undefined // ScopeDataResolver
})

Custom tag delimiters

To use custom tag delimiters and container marks (used for loops and conditions) specify the delimiters option of the template handler.

For instance, to change from {#open loop} and {/close loop} to {{>>open loop}} and {{<<close loop}} do the following:

const handler = new TemplateHandler({
    delimiters: {
        tagStart: "{{",
        tagEnd: "}}",
        containerTagOpen: ">>",
        containerTagClose: "<<"
    },
})

Advanced syntax and custom resolvers

Custom scope data resolvers gives the developer a way to hook into easy-template-x in order to change how it interprets the tag syntax.

For instance, to use Angular-like expressions you can import easy-template-x-angular-expressions by doing the following:

import { createResolver } from "easy-template-x-angular-expressions"

const handler = new TemplateHandler({
    scopeDataResolver: createResolver()
})

This allows the use of advanced syntax expressions such as:

Supported Binary Formats

The library supports the following binary formats:

• Blob (browser)
• Buffer (node)
• ArrayBuffer (browser and node)

Note - Internal API

In addition to what's described here in the readme file the library exports many more types and functions. While you are free to use them as you see fit please note that anything not documented in the readme file is considered an internal implementation detail and may break between minor versions, use at your own risk.

Philosophy

This library was originally developed as part of an app for non-English speaking k-12 teachers. As such it assumes the template editors do not necessarily have technical background and certainly no programming experience.

In order to stay friendly for such potential users it keeps the template syntax as simple as possible, limiting the required knowledge to {tags} and {#loop tags}{/loop tags} alone (and can be customized to support an alternative, potentially simpler syntax, such as {>>loop tags}{<<loop tags}).

For the same reason it supports tags with whitespace and any unicode supported alphabet such as {שם התלמיד} or {اسم المعلم}.

If your template does not need to meet such requirements, especially if they are meant to be edited by developers you can adopt a more sophisticated alternative syntax.

Changelog

The change log can be found here.