minify-xml

minify-xml

minify-xml is a lightweight and fast XML minifier for NodeJS with a command line.

Existing XML minifiers, such as pretty-data often do a pretty (phun intended) bad job minifying XML in usually only removing comments and whitespace between tags. minify-xml on the other hand also includes minification of tags, e.g. by collapsing the whitespace between multiple attributes and further minifications, such as the removal of unused namespace declarations. minify-xml is based on regular expressions and thus executes blazingly fast.

Installation

npm install minify-xml -g

Usage

const minifyXML = require("minify-xml").minify;

const xml = `<Tag xmlns:used = "used_ns" xmlns:unused = "unused_ns">
    <!--
        With the default options all comments will be removed, whitespace in
        tags, like spaces between attributes, will be collapsed / removed and
        elements without any content will be collapsed to empty tag elements
    -->
    <AnotherTag  attributeA  =  "..."  attributeB  =  "..."  >  </AnotherTag  >

    <!--
        Also any unused namespaces declarations will be removed by default,
        used namespaces however will be shortened to a minimum length possible
    -->
    <used:NamespaceTag  used:attribute  =  "..."  >
        any valid element content is left unaffected (strangely enough = " ... "
        and even > are valid characters in XML, only &lt; must always be encoded)
    </used:NamespaceTag  >

    <![CDATA[<FakeTag attr = "content in CDATA tags is not minified"></FakeTag>]]>
</Tag>`;

console.log(minifyXML(xml));

This outputs the minified XML:

<Tag xmlns:u="used_ns"><AnotherTag attributeA="..." attributeB="..."/><u:NamespaceTag u:attribute="...">
        any valid element content is left unaffected (strangely enough = " ... "
        and even > are valid characters in XML, only &lt; must always be encoded)
    </u:NamespaceTag>

    <![CDATA[<FakeTag attr = "content in CDATA tags is not minified"></FakeTag>]]>
</Tag>

Options

You may pass in the following options when calling minify:

require("minify-xml").minify(`<tag/>`, { ... });

• removeComments (default: true): Remove comments like <!-- ... -->.

• removeWhitespaceBetweenTags (default: true): Remove whitespace between tags like <anyTag /> <anyOtherTag />.

• collapseWhitespaceInTags (default: true): Collapse whitespace in tags like <anyTag attributeA = "..." attributeB = "..." />.

• collapseEmptyElements (default: true): Collapse empty elements like <anyTag anyAttribute = "..."></anyTag>.

• trimWhitespaceFromTexts (default: false): Removes leading and tailing whitespace in elements containing text only or a mixture of text and other elements like <anyTag> Hello <anyOtherTag/> World </anyTag>.

• collapseWhitespaceInTexts (default: false): Collapse whitespace in elements containing text or a mixture of text and other elements (useful for (X)HTML) like <anyTag>Hello World</anyTag>.

• removeUnusedNamespaces (default: true): Removes any namespaces from tags, which are not used anywhere in the document, like <tag xmlns:unused="any_uri" />. Notice the word anywhere here, the minifier not does consider the structure of the XML document, thus namespaces which might be only used in a certain sub-tree of elements might not be removed, even though they are not used in that sub-tree.

• removeUnusedDefaultNamespace(default: true): Removes any default namespace declaration like <tag xmlns="any_uri"/> in case there is no tag without a namespace in the whole document.

• shortenNamespaces (default: true): Shortens namespaces, like <tag xmlns:namespace="any_namespace"> to a minimal length, e.g. <tag xmlns:n="any_namespace">. First an attempt is made to shorten the existing namespace to one letter only (e.g. namespace is shortened to n), in case that letter is already taken, the shortest possible other namespace is used.

• ignoreCData (default: true): Ignores any content inside of XML CData tags <![CDATA[ any content ]]>.

CLI

You can run minify-xml from the command line to minify XML files:

minify-xml sitemap.xml
minify-xml --in-place blog.atom

Author

XML minifier by Kristian Kraljić. Original package and CLI by Mathias Bynens.

Reporting bugs

Please file any issues on Github.

License

This library is dual licensed under the MIT and Apache 2.0 licenses.

Changelog

2.2.1

Add removeUnusedDefaultNamespace to README.md