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
toh1.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, strikethrough, superscript and subscript.
-
Links.
-
Line breaks.
-
Text boxes. The contents of the text box are treated as a separate paragraph that appears after the paragraph containing the text box.
-
Comments.
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
Other supported platforms
-
Java/JVM. Available on Maven Central.
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.
The output is an HTML fragment, rather than a full HTML document, encoded with UTF-8. Since the encoding is not explicitly set in the fragment, opening the output file in a web browser may cause Unicode characters to be rendered incorrectly if the browser doesn't default to UTF-8.
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
Lines beginning with #
will be ignored.
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 = ;
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 = ; mammoth ;
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 ;
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 = ; var options = styleMap: "p[style-name='Section Title'] => h1:fresh" "p[style-name='Subsection Title'] => h2:fresh" ;mammoth;
To more easily support style maps stored in text files,
styleMap
can also be a string.
Each line is treated as a separate style mapping,
ignoring blank lines and lines starting with #
:
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: mammothimages;
Bold
By default, bold text is wrapped in <strong>
tags.
This behaviour can be changed by adding a style mapping for b
.
For instance, to wrap bold text in <em>
tags:
var mammoth = ; var options = styleMap: "b => em" ;mammoth;
Italic
By default, italic text is wrapped in <em>
tags.
This behaviour can be changed by adding a style mapping for i
.
For instance, to wrap italic text in <strong>
tags:
var mammoth = ; var options = styleMap: "i => strong" ;mammoth;
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 adding a style mapping for u
.
For instance, suppose that a source document uses underlining for emphasis.
The following will wrap any explicitly underlined source text in <em>
tags:
var mammoth = ; var options = styleMap: "u => em" ;mammoth;
Strikethrough
By default, strikethrough text is wrapped in <s>
tags.
This behaviour can be changed by adding a style mapping for strike
.
For instance, to wrap strikethrough text in <del>
tags:
var mammoth = ; var options = styleMap: "strike => del" ;mammoth;
Comments
By default, comments are ignored.
To include comments in the generated HTML,
add a style mapping for comment-reference
.
For instance:
var mammoth = ; var options = styleMap: "comment-reference => sup" ;mammoth;
Comments will be appended to the end of the document, with links to the comments wrapped using the specified style mapping.
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}
, wherepath
is the path to the .docx file.{buffer: buffer}
, wherebuffer
is a node.js Buffer containing a .docx file.
In the browser, the following inputs are supported:
{arrayBuffer: arrayBuffer}
, wherearrayBuffer
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. Ifoptions.styleMap
is a string, each line is treated as a separate style mapping, ignoring blank lines and lines starting with#
: Ifoptions.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 instyleMap
is combined with the default style map. To stop using the default style map altogether, setoptions.includeDefaultStyleMap
tofalse
. -
convertImage
: by default, images are converted to<img>
elements with the source included inline in thesrc
attribute. Set this option to an image converter to override the default behaviour. -
ignoreEmptyParagraphs
: by default, empty paragraphs are ignored. Set this option tofalse
to preserve empty paragraphs in the output. -
idPrefix
: a string to prepend to any generated IDs, such as those used by bookmarks, footnotes and endnotes. Defaults to an empty string. -
transformDocument
: if set, this function is applied to the document read from the docx file before the conversion to HTML. The API for document transforms should be considered unstable. See document transforms.
-
-
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}
, wherepath
is the path to the .docx file.{buffer: buffer}
, wherebuffer
is a node.js Buffer containing a .docx file.
In the browser, the following inputs are supported:
{arrayBuffer: arrayBuffer}
, wherearrayBuffer
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
-
mammoth.embedStyleMap(input, styleMap)
Given an existing docx file,
embedStyleMap
will generate a new docx file with the passed style map embedded.
When the new docx file is read by Mammoth,
it will use the embedded style if no explicit style map is provided.
-
input
: an object describing the source document. On node.js, the following inputs are supported:{path: path}
, wherepath
is the path to the .docx file.{buffer: buffer}
, wherebuffer
is a node.js Buffer containing a .docx file.
In the browser, the following inputs are supported:
{arrayBuffer: arrayBuffer}
, wherearrayBuffer
is an array buffer containing a .docx file.
-
styleMap
: the style map to embed. -
Returns a promise. Call
toBuffer()
on the value inside the promise to get aBuffer
representing the new document.
For instance:
mammoth; ;
Messages
Each message has the following properties:
-
type
: a string representing the type of the message, such as"warning"
or"error"
-
message
: a string containing the actual message -
error
(optional): the thrown exception that caused this message, if any
Image converters
An image converter can be created by calling mammoth.images.imgElement(func)
.
This creates an <img>
element for each image in the original docx.
func
should be a function that has one argument image
.
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, aBuffer
is returned. -
contentType
: the content type of the image, such asimage/png
.
func
should return an object (or a promise of an object) of attributes for the <img>
element.
At a minimum, this should include the src
attribute.
If any alt text is found for the image,
this will be automatically added to the element's attributes.
For instance, the following replicates the default image conversion:
mammothimages
Document transforms
The API for document transforms should be considered unstable, and may change between any versions. If you rely on this behaviour, you should pin to a specific version of mammoth.js, and test carefully before updating.
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:
{ if elementchildren var children = _; element = ...element children: children; if elementtype === "paragraph" element = ; return element;} { if elementalignment === "center" && !elementstyleId return ...element styleId: "Heading2"; else return element; } var options = transformDocument: transformElement;
The return value of transformDocument
is used during HTML generation.
The above can be written more succinctly using the helper mammoth.transforms.paragraph
:
{ if elementalignment === "center" && !elementstyleId return ...element styleId: "Heading2"; else return element; } var options = transformDocument: mammothtransforms;
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.
Writing style maps
A style map is made up of a number of style mappings separated by new lines.
Blank lines and lines starting with #
are ignored.
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
Bold
Match explicitly bold text:
b
Note that this matches text that has had bold explicitly applied to it. It will not match any text that is bold because of its paragraph or run style.
Italic
Match explicitly italic text:
i
Note that this matches text that has had italic explicitly applied to it. It will not match any text that is italic because of its paragraph or run style.
Underline
Match explicitly underlined text:
u
Note that this matches text that has had underline explicitly applied to it. It will not match any text that is underlined because of its paragraph or run style.
Strikethough
Match explicitly struckthrough text:
strike
Note that this matches text that has had strikethrough explicitly applied to it. It will not match any text that is struckthrough because of its paragraph or run style.
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
1.0.0
The convertUnderline
option is no longer supported.
Use style mappings to control how underlines are handled.
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 thestyleName
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:
-
- Document transforms
-
- Underline support
-
- node.js
Buffer
support - UTF8 BOM handling
- node.js
-
- Markdown support
-
- Internal hyperlink support
-
- Supporting styles defined without names