fix: stop requiring shiki for type-checking streamdown

.changeset/fix-shiki-type-declarations.md

@@ -0,0 +1,7 @@
+---
+"streamdown": patch
+---
+
+Fix type declarations requiring a `shiki` install.
+
+`BundledLanguage`, `BundledTheme`, and `ThemeRegistrationAny` are now defined locally and re-exported from `streamdown`, so consumers can type-check without installing `shiki`. Runtime highlighting remains in `@streamdown/code`, which still depends on `shiki`.

packages/streamdown/index.tsx

@@ -46,11 +46,6 @@ import {
 } from "./lib/translations-context";
 import { createCn } from "./lib/utils";
 
-export type {
-  BundledLanguage,
-  BundledTheme,
-  ThemeRegistrationAny,
-} from "shiki";
 export type { AnimateOptions } from "./lib/animate";
 // biome-ignore lint/performance/noBarrelFile: "required"
 export { createAnimatePlugin } from "./lib/animate";
@@ -73,6 +68,8 @@ export type {
 export { defaultUrlTransform } from "./lib/markdown";
 export { parseMarkdownIntoBlocks } from "./lib/parse-blocks";
 export type {
+  BundledLanguage,
+  BundledTheme,
   CjkPlugin,
   CodeHighlighterPlugin,
   CustomRenderer,
@@ -82,6 +79,7 @@ export type {
   MathPlugin,
   PluginConfig,
   ThemeInput,
+  ThemeRegistrationAny,
 } from "./lib/plugin-types";
 export {
   TableCopyDropdown,

packages/streamdown/lib/code-block/highlighted-body.tsx

@@ -1,8 +1,7 @@
 import { type HTMLAttributes, useContext, useEffect, useState } from "react";
-import type { BundledLanguage } from "shiki";
 import { StreamdownContext } from "../../index";
 import { useCodePlugin } from "../plugin-context";
-import type { HighlightResult } from "../plugin-types";
+import type { BundledLanguage, HighlightResult } from "../plugin-types";
 import { CodeBlockBody } from "./body";
 
 type HighlightedCodeBlockBodyProps = HTMLAttributes<HTMLDivElement> & {

packages/streamdown/lib/plugin-types.ts

@@ -1,11 +1,17 @@
 import type { MermaidConfig } from "mermaid";
 import type React from "react";
+import type { Pluggable } from "unified";
 import type {
   BundledLanguage,
   BundledTheme,
   ThemeRegistrationAny,
-} from "shiki";
-import type { Pluggable } from "unified";
+} from "./shiki-types";
+
+export type {
+  BundledLanguage,
+  BundledTheme,
+  ThemeRegistrationAny,
+} from "./shiki-types";
 
 export type ThemeInput = BundledTheme | ThemeRegistrationAny;
 
@@ -42,30 +48,34 @@ export interface HighlightOptions {
 
 /**
  * Plugin for code syntax highlighting (Shiki)
+ *
+ * Method syntax is intentional: parameter types stay bivariant so plugins
+ * from `@streamdown/code` (which use Shiki's narrower language/theme unions)
+ * remain assignable without requiring a `shiki` type dependency here.
  */
 export interface CodeHighlighterPlugin {
   /**
    * Get list of supported languages
    */
-  getSupportedLanguages: () => BundledLanguage[];
+  getSupportedLanguages(): BundledLanguage[];
   /**
    * Get the configured themes
    */
-  getThemes: () => [ThemeInput, ThemeInput];
+  getThemes(): [ThemeInput, ThemeInput];
   /**
    * Highlight code and return tokens
    * Returns null if highlighting not ready yet (async loading)
    * Use callback for async result
    */
-  highlight: (
+  highlight(
     options: HighlightOptions,
     callback?: (result: HighlightResult) => void
-  ) => HighlightResult | null;
+  ): HighlightResult | null;
   name: "shiki";
   /**
    * Check if language is supported
    */
-  supportsLanguage: (language: BundledLanguage) => boolean;
+  supportsLanguage(language: BundledLanguage): boolean;
   type: "code-highlighter";
 }
 

packages/streamdown/lib/shiki-types.ts

@@ -0,0 +1,43 @@
+/**
+ * Types compatible with Shiki, defined locally so consumers of `streamdown`
+ * can type-check without installing the `shiki` package.
+ *
+ * Runtime highlighting lives in `@streamdown/code`, which depends on `shiki`.
+ * Streamdown only needs these types for its plugin API surface (`shikiTheme`,
+ * `CodeHighlighterPlugin`, and related re-exports).
+ *
+ * @see https://shiki.style/languages
+ * @see https://shiki.style/themes
+ */
+
+/**
+ * Language identifier for syntax highlighting.
+ * Compatible with Shiki's `BundledLanguage`.
+ */
+export type BundledLanguage = string;
+
+/**
+ * Built-in theme name for syntax highlighting.
+ * Compatible with Shiki's `BundledTheme`.
+ */
+export type BundledTheme = string;
+
+/**
+ * Custom theme registration object compatible with Shiki's
+ * `ThemeRegistrationAny` (raw, resolved, or intermediate forms).
+ *
+ * Kept structural and permissive so custom theme objects from
+ * `@streamdown/code` / Shiki remain assignable without a type dependency.
+ */
+export interface ThemeRegistrationAny {
+  bg?: string;
+  colors?: Record<string, string>;
+  displayName?: string;
+  fg?: string;
+  name?: string;
+  semanticHighlighting?: boolean;
+  semanticTokenColors?: Record<string, unknown>;
+  settings?: unknown[];
+  tokenColors?: unknown[];
+  type?: "light" | "dark";
+}

packages/streamdown/package.json

@@ -52,7 +52,6 @@
     "react-markdown": "^10.1.0",
     "rehype-parse": "^9.0.1",
     "rehype-stringify": "^10.0.1",
-    "shiki": "^3.19.0",
     "tsup": "^8.5.1",
     "vitest": "^4.0.15"
   },