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mammoth_custom

0.3.28 • Public • Published

Mammoth .docx to HTML converter

Mammoth is designed to convert .docx documents, such as those created by Microsoft Word, and convert them to HTML. Mammoth aims to produce simple and clean HTML by using semantic information in the document, and ignoring other details. For instance, Mammoth converts any paragraph with the style Heading 1 to h1 elements, rather than attempting to exactly copy the styling (font, text size, colour, etc.) of the heading.

There's a large mismatch between the structure used by .docx and the structure of HTML, meaning that the conversion is unlikely to be perfect for more complicated documents. Mammoth works best if you only use styles to semantically mark up your document.

The following features are currently supported:

  • Headings.

  • Lists.

  • Customisable mapping from your own docx styles to HTML. For instance, you could convert WarningHeading to h1.warning by providing an appropriate style mapping.

  • Tables. The formatting of the table itself, such as borders, is currently ignored, but the formatting of the text is treated the same as in the rest of the document.

  • Footnotes and endnotes.

  • Images.

  • Bold, italics, underlines, superscript and subscript.

  • Links.

  • Line breaks.

Web demo

The easiest way to try out mammoth is to use the web demo:

  • Clone this repository
  • Run make setup
  • Open browser-demo/index.html in a web browser

Installation

npm install mammoth

Usage

CLI

You can convert docx files by passing the path to the docx file and the output file. For instance:

mammoth document.docx output.html

If no output file is specified, output is written to stdout instead.

Images

By default, images are included inline in the output HTML. If an output directory is specified by --output-dir, the images are written to separate files instead. For instance:

mammoth document.docx --output-dir=output-dir

Existing files will be overwritten if present.

Styles

A custom style map can be read from a file using --style-map. For instance:

mammoth document.docx output.html --style-map=custom-style-map

Where custom-style-map looks something like:

p[style-name='Aside Heading'] => div.aside > h2:fresh
p[style-name='Aside Text'] => div.aside > p:fresh

Markdown

Using --output-format=markdown will cause Markdown to be generated. For instance:

mammoth document.docx --output-format=markdown

Markdown support is still in its early stages, so you may find some features are unsupported.

Library

In node.js, mammoth can be required in the usual way:

var mammoth = require("mammoth");

To generate a standalone JavaScript file for the browser, use mammoth.browser.js (generate using make setup if it is not already present). This uses any loaded module system. If no module system is found, mammoth is set as a window global.

Basic conversion

To convert an existing .docx file to HTML, use mammoth.convertToHtml:

var mammoth = require("mammoth");
 
mammoth.convertToHtml({path: "path/to/document.docx"})
    .then(function(result){
        var html = result.value; // The generated HTML
        var messages = result.messages; // Any messages, such as warnings during conversion
    })
    .done();

Note that mammoth.convertToHtml returns a promise.

You can also extract the raw text of the document by using mammoth.extractRawText. This will ignore all formatting in the document. Each paragraph is followed by two newlines.

mammoth.extractRawText({path: "path/to/document.docx"})
    .then(function(result){
        var text = result.value; // The raw text
        var messages = result.messages;
    })
    .done();

Custom style map

By default, Mammoth maps some common .docx styles to HTML elements. For instance, a paragraph with the style name Heading 1 is converted to a h1 element. You can pass in a custom map for styles by passing an options object with a styleMap property as a second argument to convertToHtml. A description of the syntax for style maps can be found in the section "Writing style maps". For instance, if paragraphs with the style name Section Title should be converted to h1 elements, and paragraphs with the style name Subsection Title should be converted to h2 elements:

var mammoth = require("mammoth");
 
var options = {
    styleMap: [
        "p[style-name='Section Title'] => h1:fresh",
        "p[style-name='Subsection Title'] => h2:fresh"
    ]
};
mammoth.convertToHtml({path: "path/to/document.docx"}, options);

To more easily support style maps stored in text files, styleMap can also be a string. Each non-blank line is treated as a separate style mapping:

var options = {
    styleMap: "p[style-name='Section Title'] => h1:fresh\n" +
        "p[style-name='Subsection Title'] => h2:fresh"
};

User-defined style mappings are used in preference to the default style mappings. To stop using the default style mappings altogether, set options.includeDefaultStyleMap to false:

var options = {
    styleMap: [
        "p[style-name='Section Title'] => h1:fresh",
        "p[style-name='Subsection Title'] => h2:fresh"
    ],
    includeDefaultStyleMap: false
};

Custom image handlers

By default, images are converted to <img> elements with the source included inline in the src attribute. This behaviour can be changed by setting the convertImage option to an image converter .

For instance, the following would replicate the default behaviour:

var options = {
    convertImage: mammoth.images.inline(function(element) {
        return element.read("base64").then(function(imageBuffer) {
            return {
                src: "data:" + element.contentType + ";base64," + imageBuffer
            };
        });
    })
};

Underline

By default, the underlining of any text is ignored since underlining can be confused with links in HTML documents. This behaviour can be changed by setting the convertUnderline option to mammoth.underline.element(name).

For instance, suppose that a source document uses underlining for emphasis. The following will wrap any underlined source text in <em> tags:

var options = {
    convertUnderline: mammoth.underline.element("em")
};

Document transforms

Mammoth allows a document to be transformed before it is converted. For instance, suppose that document has not been semantically marked up, but you know that any centre-aligned paragraph should be a heading. You can use the transformDocument argument to modify the document appropriately:

function transformElement(element) {
    if (element.children) {
        element.children.forEach(transformElement);
    }
    if (element.type === "paragraph") {
        if (element.alignment === "center" && !element.styleId) {
            element.styleId = "Heading2";
        }
    }
    return element;
}
 
var options = {
    transformDocument: transformElement
};

The return value of transformDocument is used during HTML generation. The original document (and any child elements) can be safely modified.

The above can be written more succinctly using the helper mammoth.transforms.paragraph:

 
function transformParagraph(element) {
    if (element.alignment === "center" && !element.styleId) {
        element.styleId = "Heading2";
    }
    return element;
}
 
var options = {
    transformDocument: mammoth.transforms.paragraph(transformParagraph)
};

API

mammoth.convertToHtml(input, options)

Converts the source document to HTML.

  • input: an object describing the source document. On node.js, the following inputs are supported:

    • {path: path}, where path is the path to the .docx file.
    • {buffer: buffer}, where buffer is a node.js Buffer containing a .docx file.

    In the browser, the following inputs are supported:

    • {arrayBuffer: arrayBuffer}, where arrayBuffer is an array buffer containing a .docx file.

  • options (optional): options for the conversion. May have the following properties:

    • styleMap: controls the mapping of Word styles to HTML. If options.styleMap is a string, each non-blank line is treated as a separate style mapping. If options.styleMap is an array, each element is expected to be a string representing a single style mapping. See "Writing style maps" for a reference to the syntax for style maps.

    • includeDefaultStyleMap: by default, the style map passed in styleMap is combined with the default style map. To stop using the default style map altogether, set options.includeDefaultStyleMap to false.

    • transformDocument: if set, this function is applied to the document read from the docx file before the conversion to HTML.

    • convertImage: by default, images are converted to <img> elements with the source included inline in the src attribute. Set this option to an image converter to override the default behaviour.

    • convertUnderline: by default, the underlining of any text is ignored. Set this option to mammoth.underline.element(name) to override the default behaviour.

    • ignoreEmptyParagraphs: by default, empty paragraphs are ignored. Set this option to false to preserve empty paragraphs in the output.

  • Returns a promise containing a result. This result has the following properties:

    • value: the generated HTML

    • messages: any messages, such as errors and warnings, generated during the conversion

mammoth.convertToMarkdown(input, options)

Converts the source document to Markdown. This behaves the same as convertToHtml, except that the value property of the result contains Markdown rather than HTML.

mammoth.extractRawText(input)

Extract the raw text of the document. This will ignore all formatting in the document. Each paragraph is followed by two newlines.

  • input: an object describing the source document. On node.js, the following inputs are supported:

    • {path: path}, where path is the path to the .docx file.
    • {buffer: buffer}, where buffer is a node.js Buffer containing a .docx file.

    In the browser, the following inputs are supported:

    • {arrayBuffer: arrayBuffer}, where arrayBuffer is an array buffer containing a .docx file.

  • Returns a promise containing a result. This result has the following properties:

    • value: the raw text

    • messages: any messages, such as errors and warnings

Messages

Each message has the following properties:

  • type: a string representing the type of the message, such as "warning"

  • message: a string containing the actual message

Image converters

An inline image converter can be created by calling mammoth.images.inline(func). This creates an inline <img> element for each image in the original docx. func should be a function that has one argument called element. This argument is the image element being converted, and has the following properties:

  • read([encoding]): read the image file with the specified encoding. If no encoding is specified, a Buffer is returned.

  • contentType: the content type of the image, such as image/png.

func should return an object (or a promise containing an object) with a src property, which will be used as the src attribute on the <img> element.

For instance, the following replicates the default image conversion:

mammoth.images.inline(function(element) {
    return element.read("base64").then(function(imageBuffer) {
        return {
            src: "data:" + element.contentType + ";base64," + imageBuffer
        };
    });
})

mammoth.transforms.paragraph(transformParagraph)

Returns a function that can be used as the transformDocument option. This will apply the function transformParagraph to each paragraph element. transformParagraph should return the new paragraph, and is allowed to mutate the original paragraph.

Writing style maps

A style map is made up of a number of style mappings separated by new lines.

A style mapping has two parts:

  • On the left, before the arrow, is the document element matcher.
  • On the right, after the arrow, is the HTML path.

When converting each paragraph, Mammoth finds the first style mapping where the document element matcher matches the current paragraph. Mammoth then ensures the HTML path is satisfied.

Freshness

When writing style mappings, it's helpful to understand Mammoth's notion of freshness. When generating, Mammoth will only close an HTML element when necessary. Otherwise, elements are reused.

For instance, suppose one of the specified style mappings is p[style-name='Heading 1'] => h1. If Mammoth encounters a .docx paragraph with the style name Heading 1, the .docx paragraph is converted to a h1 element with the same text. If the next .docx paragraph also has the style name Heading 1, then the text of that paragraph will be appended to the existing h1 element, rather than creating a new h1 element.

In most cases, you'll probably want to generate a new h1 element instead. You can specify this by using the :fresh modifier:

p[style-name='Heading 1'] => h1:fresh

The two consective Heading 1 .docx paragraphs will then be converted to two separate h1 elements.

Reusing elements is useful in generating more complicated HTML structures. For instance, suppose your .docx contains asides. Each aside might have a heading and some body text, which should be contained within a single div.aside element. In this case, style mappings similar to p[style-name='Aside Heading'] => div.aside > h2:fresh and p[style-name='Aside Text'] => div.aside > p:fresh might be helpful.

Document element matchers

Paragraphs and runs

Match any paragraph:

p

Match any run:

r

To match a paragraph or run with a specific style, you can reference the style by name. This is the style name that is displayed in Microsoft Word or LibreOffice. For instance, to match a paragraph with the style name Heading 1:

p[style-name='Heading 1']

Styles can also be referenced by style ID. This is the ID used internally in the .docx file. To match a paragraph or run with a specific style ID, append a dot followed by the style ID. For instance, to match a paragraph with the style ID Heading1:

p.Heading1

HTML paths

Single elements

The simplest HTML path is to specify a single element. For instance, to specify an h1 element:

h1

To give an element a CSS class, append a dot followed by the name of the class:

h1.section-title

To require that an element is fresh, use :fresh:

h1:fresh

Modifiers must be used in the correct order:

h1.section-title:fresh

Nested elements

Use > to specify nested elements. For instance, to specify h2 within div.aside:

div.aside > h2

You can nest elements to any depth.

Upgrading to later versions

0.3.0

If you've defined custom style maps or used a document transform, you will likely need to change your usage slightly. Otherwise, you should be able to continue using Mammoth as before.

Custom style maps

Prior to 0.3.0, Mammoth matched docx paragraphs using style IDs e.g. p.Heading1. These IDs are used internally in the docx format, and are distinct from the style name i.e. the name shown by Microsoft Word or LibreOffice. Although Mammoth still supports matching styles by ID, matching styles by name is preferred. For instance, instead of:

p.AsideHeading => h1

prefer:

p[style-name='Aside Heading'] => h1

Document transforms

Prior to 0.3.0, Mammoth (misleadingly) assigned the style ID to a property called styleName. The style ID is now assigned to a more appropriate property, styleId. The styleName property is now set to the name of the style. To preserve existing behaviour, any existing document transforms should be rewritten in one of two ways:

  • Set the styleId property instead of the styleName property

  • Set the styleName property to the name of the style, rather than the ID

0.2.0

The function mammoth.style() was renamed to mammoth.styleMapping().

Acknowledgements

Thanks to the following people for their contributions to Mammoth:

Readme

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License

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