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UNUSED_EXTERNAL_IMPORT build warning with Vite, Rollup, or Nuxt

当打包使用 @supabase/supabase-js 的应用时，你可能会看到类似这样的警告：

🌐 When bundling an application that uses @supabase/supabase-js, you may see warnings like:

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"PostgrestError" is imported from external module "@supabase/postgrest-js" but never used in "...supabase-js/dist/index.mjs".
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"FunctionRegion", "FunctionsError", "FunctionsFetchError", "FunctionsHttpError" and "FunctionsRelayError" are imported from external module "@supabase/functions-js" but never used in "...".

这是误报——你的包是正确的，没有缺少任何代码。

为什么会这样 #

🌐 Why this happens

@supabase/supabase-js 重新导出像 PostgrestError 和 FunctionsError 这样的错误类型，所以你可以直接从 @supabase/supabase-js 导入它们。构建工具会把来自同一个包的所有导入合并成输出里的单个语句：

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// dist/index.mjs (simplified)
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import { PostgrestClient, PostgrestError } from '@supabase/postgrest-js'
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//       ^ used internally    ^ re-exported for you

Vite/Rollup 会检查从那个 import 导入的哪些名字在 代码主体中 被引用，并将 PostgrestError 标记为未使用，因为它只出现在 export 语句中——没有被调用或赋值。实际上导出本身才是它真正的使用，但这个检查不会考虑 re-export。Tree-shaking 和打包大小不受影响。

🌐 Vite/Rollup checks which names from that import are referenced in the code body and flags PostgrestError as unused, because it only appears in an export statement — not called or assigned. The export itself is the real usage, but this check doesn't account for re-exports. Tree-shaking and bundle size are unaffected.

关闭警告 #

🌐 Suppress the warning

Vite / Rollup（vite.config.js 或 rollup.config.js#

🌐 Vite / Rollup (vite.config.js or rollup.config.js)

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export default {
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  build: {
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    rollupOptions: {
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      onwarn(warning, warn) {
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        if (warning.code === 'UNUSED_EXTERNAL_IMPORT' && warning.exporter?.includes('@supabase/'))
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          return
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        warn(warning)
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      },
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    },
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  },
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}

Nuxt（nuxt.config.ts#

🌐 Nuxt (nuxt.config.ts)

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export default defineNuxtConfig({
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  vite: {
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    build: {
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      rollupOptions: {
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        onwarn(warning, warn) {
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          if (warning.code === 'UNUSED_EXTERNAL_IMPORT' && warning.exporter?.includes('@supabase/'))
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            return
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          warn(warning)
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        },
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      },
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    },
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  },
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})