awaforge

markupCompatibility

AGPL-3.0-onlyRelease 2L4

Markup Compatibility (ECMA-376 part 3) — resolves mc:AlternateContent, mc:Ignorable, mc:ProcessContent.

Module markupCompatibility | Source packages/front/office/ooxml/src/mc/markupCompatibility.js | Deps xml | Worker-safe yes

Without MC, a strict parser breaks on every modern .docx/.xlsx/.pptx (the w14/w15/x14/p14 extensions are everywhere). Three constructs: mc:AlternateContent (conditional selection), mc:Ignorable (droppable prefixes), mc:ProcessContent (drop the wrapper, keep the content). The module works by in-place mutation; the returned tree is free of mc:*.

Resolve

const mc = runtime.resolve('markupCompatibility');
// Returns: { process, wrapAlternateContent, setIgnorable, MC_NS }

API

Method Signature Returns
process (root: element, options?) => element The same root, with mc:* resolved.
wrapAlternateContent ({ choices, fallback }) => element <mc:AlternateContent> builder.
setIgnorable (rootEl, prefixes: string|string[]) => rootEl Sets xmlns:mc + mc:Ignorable.
MC_NS string constant The MC 2006 namespace.

process options

Option Type Default Description
supportedPrefixes string[] [] Prefixes the caller "understands". An mc:Choice wins when all of its Requires are supported.
preserveAlternateContent boolean false When true, leaves mc:AlternateContent untouched (only mc:Ignorable is stripped).
keepElements string[] [] Qualified element names (prefix:localName) that survive even when their prefix is ignorable, together with their whole subtree: attributes and descendants are kept, no ignorable-prefix dropping happens inside. mc:AlternateContent and mc:* attributes inside are still resolved. Every other element of the same prefix is dropped as usual. Matching is by prefix, like the rest of this module: a document binding the same namespace to another prefix is not recognised.

Examples

Clean a document before typed parsing

const mc = runtime.resolve('markupCompatibility');
const xml = runtime.resolve('xml');
const root = xml.parse(documentXml);
mc.process(root, { supportedPrefixes: ['w14'] });
// w14 Choice branches kept, w15 and the rest dropped to the Fallback.

Keep two named elements of an ignorable namespace

const root = xml.parse(
    '<w:sdtPr xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"'
    + ' mc:Ignorable="w15">'
    + '<w15:repeatingSection><w15:sectionTitle w:val="Rows"/></w15:repeatingSection>'
    + '<w15:color w:val="FF0000"/>'
    + '</w:sdtPr>');
mc.process(root, {
    keepElements: ['w15:repeatingSection', 'w15:repeatingSectionItem']
});
// root.children: [<w15:repeatingSection> with its <w15:sectionTitle> child];
// <w15:color> is dropped. `docx.read` processes word/document.xml and every
// header, footer, footnotes, endnotes and comments part this way.

Producer — wrap a w14 extension

const alt = mc.wrapAlternateContent({
    choices: [{ requires: 'w14', element: w14Variant }],
    fallback: vanillaVariant
});
mc.setIgnorable(rootEl, ['w14', 'w15']);

Notes

  • Selection order follows ECMA-376 part 3 §10.1.2.4: the first Choice satisfying all of its Requires, else the Fallback, else nothing.
  • mc:Ignorable is inherited across the subtree via a Set threaded through the recursive walks.
  • Nested mc:AlternateContent elements are resolved recursively.
  • The mc:* attributes (Ignorable/PreserveElements/PreserveAttributes/MustUnderstand/ProcessContent) are removed in place.

See also