Remove markdown-it

[compulim]

Changelog Entry

Changed

• Removed markdown-it and completed migration to micromark, in PR #5825, by @compulim

Description

We have planned to fade out markdown-it since #5330. In this PR, we completely migrate off markdown-it by moving localization logic from markdown-it to micromark.

Design

Specific Changes

• Refactored "better link" mod from bundle to component
  • The key feature we use "better link" is for localizing "Send failed. Retry" prompt, which the "Retry" link is replaced as a button
• useLocalizer now use micromark instead of markdown-it
• Added new dataset options to "better link" mod

• I have added tests and executed them locally
• I have updated CHANGELOG.md
• I have updated documentation

Review Checklist

This section is for contributors to review your work.

• Accessibility reviewed (tab order, content readability, alt text, color contrast)
• Browser and platform compatibilities reviewed
• CSS styles reviewed (minimal rules, no z-index)
• Documents reviewed (docs, samples, live demo)
• Internationalization reviewed (strings, unit formatting)
• package.json and package-lock.json reviewed
• Security reviewed (no data URIs, check for nonce leak)
• Tests reviewed (coverage, legitimacy)

[Copilot]

Pull request overview

This PR completes the migration away from markdown-it by moving localization and internal inline Markdown rendering to micromark, and by extracting shared link/document utilities into a new component-better-link package.

Changes:

• Adds @msinternal/botframework-webchat-component-better-link for DOM-based link decoration and fragment parsing/serialization.
• Reworks LocalizedString, InlineMarkdown, toast inline Markdown rendering, and retry-link rendering to use micromark.
• Removes markdown-it-specific helpers, hooks, context values, and package dependencies.

Reviewed changes

Copilot reviewed 55 out of 58 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
packages/fluent-theme/src/components/preChatActivity/PreChatMessageActivity.tsx	Adapts localizer argument to stricter string typing.
packages/fluent-theme/src/components/activity/CopilotMessageHeader.tsx	Defaults bot title to an empty string for localizer compatibility.
packages/component/src/Utils/LocalizedString.tsx	Reimplements localized Markdown rendering via micromark and better-link DOM decoration.
packages/component/src/Utils/InlineMarkdown.tsx	Adds TSX micromark implementation for inline reference links.
packages/component/src/Utils/InlineMarkdown.js	Removes old markdown-it implementation.
packages/component/src/Utils/betterLinks.ts	Removes old markdown-it better-links plugin.
packages/component/src/Utils/walkMarkdownTokens.js	Removes markdown token walker utility.
packages/component/src/Utils/walkMarkdownTokens.spec.js	Removes tests for deleted token walker.
packages/component/src/Utils/updateMarkdownAttrs.js	Removes markdown-it attribute updater.
packages/component/src/Utils/updateMarkdownAttrs.spec.js	Removes tests for deleted updater.
packages/component/src/Utils/addTargetBlankToHyperlinks.ts	Adds DOM-based target/rel link decoration.
packages/component/src/Utils/addTargetBlankToHyperlinks.spec.ts	Adds replacement tests for DOM-based link decoration.
packages/component/src/Utils/addTargetBlankToHyperlinksMarkdown.js	Removes markdown-it token-based link decoration.
packages/component/src/Utils/addTargetBlankToHyperlinksMarkdown.spec.js	Removes tests for deleted markdown-it helper.
packages/component/src/providers/CustomElements/customElements/CodeBlock.ts	Updates fragment parser import to new package.
packages/component/src/private/renderMarkdownInline.ts	Adds standalone inline Markdown renderer for internal UI.
packages/component/src/hooks/useStreamingMarkdownWithDefinitions.ts	Updates fragment parser import to new package.
packages/component/src/hooks/useRenderMarkdownAsHTML.ts	Updates parser/serializer imports to new package.
packages/component/src/hooks/internal/WebChatUIContext.ts	Removes internal markdown-it context fields.
packages/component/src/hooks/internal/useInternalRenderMarkdownInline.js	Removes obsolete internal render hook.
packages/component/src/hooks/internal/useInternalMarkdownIt.js	Removes obsolete markdown-it hook.
packages/component/src/Composer.tsx	Removes markdown-it setup and context plumbing.
packages/component/src/boot/internal.ts	Re-exports better-link utilities from the new package.
packages/component/src/BasicToaster.js	Uses standalone inline Markdown renderer.
packages/component/src/BasicToast.js	Uses standalone inline Markdown renderer.
packages/component/src/ActivityStatus/SendStatus/private/SendFailedRetry.tsx	Adds TSX retry message component using InlineMarkdown.
packages/component/src/ActivityStatus/SendStatus/private/SendFailedRetry.js	Removes old JS retry component.
packages/component/package.json	Swaps markdown-it for micromark and new local package dependency.
packages/component-better-link/package.json	Adds new better-link package manifest.
packages/component-better-link/tsup.config.ts	Adds build config for the new package.
packages/component-better-link/src/tsconfig.json	Adds TypeScript config for the new package.
packages/component-better-link/src/index.ts	Exposes better-link package API.
packages/component-better-link/src/betterLinkDocumentMod.ts	Centralizes DOM link decoration logic.
packages/component-better-link/src/*.spec.ts	Adds/updates better-link behavior tests.
packages/component-better-link/src/private/copyAttribute.ts	Adds attribute-copy helper for anchor-to-button conversion.
packages/component-better-link/src/private/copyAttribute.spec.ts	Tests attribute-copy helper.
packages/component-better-link/src/parseDocumentFragmentFromString.ts	Adds fragment parser utility.
packages/component-better-link/src/serializeDocumentFragmentIntoString.ts	Adds fragment serializer utility.
packages/component-better-link/src/stripParagraphContainer.ts	Adds paragraph wrapper stripping utility.
packages/component-better-link/.gitignore	Adds package ignore rules.
packages/component-better-link/.eslintrc.yml	Adds lint config for new package.
packages/bundle/src/markdown/renderMarkdown.ts	Imports better-link decoration via component internal exports.
packages/bundle/src/markdown/createStreamingRenderer.ts	Uses shared better-link decoration in streaming renderer.
packages/bundle/src/markdown/private/createDecorate.ts	Updates better-link decoration type import.
packages/api/src/hooks/useLocalizer.ts	Adds localizer overloads and refactors substitution handling.
package.json	Registers new workspace and scripts.
package-lock.json	Updates workspace and dependency lock data.
lint-staged.config.js	Adds lint-staged rule for new package.

Comments suppressed due to low confidence (4)

packages/component-better-link/src/betterLinkDocumentMod.ts:76

• Passing undefined through ?? false makes unspecified decoration fields remove existing attributes. For example, callers that only add rel/target will now strip an existing aria-label, class, or title from the link. Leave attributes unchanged when the decoration field is omitted, and reserve false for explicit removal.
  packages/component-better-link/src/betterLinkDocumentMod.ts:111
• The same ?? false behavior removes existing rel/target attributes whenever a decorator omits those fields. That changes links even when the caller only intended another decoration, so omitted fields should be left unchanged.
  packages/component-better-link/src/betterLinkDocumentMod.ts:56
• setOrRemoveAttribute treats an empty string as falsy and neither sets nor removes the attribute, even though the attribute setter type allows any string. This breaks legitimate empty-string values such as clearing an aria-label while keeping the attribute present.
  packages/component-better-link/src/betterLinkDocumentMod.ts:121
• The denylist skips constructor, proto, and prototype, but it misses the standard __proto__ key. Since this code writes dynamic keys via bracket access, include __proto__ in the forbidden set before assigning to datasetTarget.dataset.

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[OEvgeny]

In future we should fold it into some internal package as we have the mod in bundle as well.