fix: Intl.Segmentor works in demo on firefox

Author: ota-meshi

docs/.vitepress/theme/index.ts

@@ -11,20 +11,42 @@ if (typeof window !== "undefined") {
 }
 import type { Theme } from "vitepress"
 import DefaultTheme from "vitepress/theme"
-// @ts-expect-error -- ignore
 import Layout from "./Layout.vue"
-// @ts-expect-error -- ignore
-import ESLintCodeBlock from "./components/eslint-code-block.vue"
-// @ts-expect-error -- ignore
-import PlaygroundBlock from "./components/playground-block.vue"
 
 const theme: Theme = {
     ...DefaultTheme,
     Layout,
-    enhanceApp(ctx) {
+    async enhanceApp(ctx) {
         DefaultTheme.enhanceApp(ctx)
+
+        if (typeof Intl.Segmenter === "undefined") {
+            await setupIntlSegmenter()
+        }
+
+        const ESLintCodeBlock = await import(
+            "./components/eslint-code-block.vue"
+        ).then((m) => m.default ?? m)
+        const PlaygroundBlock = await import(
+            "./components/playground-block.vue"
+        ).then((m) => m.default ?? m)
         ctx.app.component("eslint-code-block", ESLintCodeBlock)
         ctx.app.component("playground-block", PlaygroundBlock)
     },
 }
 export default theme
+
+// We can remove this polyfill once Firefox supports Intl.Segmenter.
+async function setupIntlSegmenter() {
+    // For Firefox
+    const [{ createIntlSegmenterPolyfill }, breakIteratorUrl] =
+        await Promise.all([
+            import("intl-segmenter-polyfill"),
+            import(
+                // @ts-expect-error -- polyfill
+                "intl-segmenter-polyfill/dist/break_iterator.wasm?url"
+            ).then((m) => m.default ?? m),
+        ])
+
+    // @ts-expect-error -- polyfill
+    Intl.Segmenter = await createIntlSegmenterPolyfill(fetch(breakIteratorUrl))
+}

package-lock.json

@@ -87,6 +87,7 @@
         "eslint-plugin-regexp": "~1.15.0",
         "eslint-plugin-vue": "^9.0.0",
         "eslint-plugin-yml": "^1.0.0",
+        "intl-segmenter-polyfill": "^0.4.4",
         "markdownlint-cli": "^0.37.0",
         "mocha": "^10.0.0",
         "mocha-chai-jest-snapshot": "^1.1.3",