"Cannot use import statement outside a module" when using the module with Vite

[johan-jnn]

Issue

When using sanity-plugin-singleton-tools with vite (+ svelte but i'm not sure it's related), I get a SyntaxError: Cannot use import statement outside a module.

Reproduction

Create a vite + sanity project (without bundlers as modules).
I'm using this configuration :

// sanity.config.ts

import { defineConfig } from "sanity";
import { structureTool } from "sanity/structure";
import { codeInput } from "@sanity/code-input";
import { dataset, projectId } from "./config.json";
import { singletonTools } from "sanity-plugin-singleton-tools";

export default defineConfig({
  projectId,
  dataset,
  basePath: "/studio",
  plugins: [structureTool(), codeInput(), singletonTools()],
  schema: {
    // ...
  },
  form: {},
});

// vite.config.ts

import { sveltekit } from "@sveltejs/kit/vite";
import { defineConfig } from "vite";

export default defineConfig({
  plugins: [sveltekit()],
  envPrefix: ["ENV_", "SANITY_STUDIO_"],
  css: {
    preprocessorOptions: {
      sass: {
        silenceDeprecations: ["legacy-js-api"],
      },
    },
  },
});

Note : I have no typing error using these configurations.
Error shown in the console :

C:\...\project_folder\node_modules\sanity-plugin-singleton-tools\dist\index.esm.js:1
import { DocumentIcon } from "@sanity/icons";
^^^^^^

SyntaxError: Cannot use import statement outside a module
    at wrapSafe (node:internal/modules/cjs/loader:1281:20)
    at Module._compile (node:internal/modules/cjs/loader:1321:27)
    at Module._extensions..js (node:internal/modules/cjs/loader:1416:10)
    at Module.load (node:internal/modules/cjs/loader:1208:32)
    at Module._load (node:internal/modules/cjs/loader:1024:12)
    at cjsLoader (node:internal/modules/esm/translators:348:17)
    at ModuleWrap.<anonymous> (node:internal/modules/esm/translators:297:7)
    at ModuleJob.run (node:internal/modules/esm/module_job:222:25)
    at async ModuleLoader.import (node:internal/modules/esm/loader:316:24)
    at async nodeImport (file:///C:/.../project_folder/node_modules/vite/dist/node/chunks/dep-BWSbWtLw.js:53056:15)

Dependencies versions

{
	"devDependencies": {
		"@portabletext/svelte": "^2.1.11",
		"@sveltejs/adapter-auto": "^3.3.1",
		"@sveltejs/kit": "^2.8.0",
		"@sveltejs/vite-plugin-svelte": "^4.0.0",
		"@types/gsap": "^3.0.0",
		"dotenv": "^16.4.5",
		"sass": "^1.80.6",
		"svelte": "^5.1.12",
		"svelte-check": "^4.0.6",
		"typescript": "^5.6.3",
		"vite": "^5.4.10"
	},
	"dependencies": {
		"@danteissaias/groq-builder": "^0.9.2",
		"@sanity/client": "^6.22.3",
		"@sanity/code-input": "^4.1.4",
		"@types/three": "^0.169.0",
		"gsap": "^3.12.5",
		"postprocessing": "^6.36.4",
		"sanity": "^3.63.0",
		"sanity-plugin-singleton-tools": "^1.1.0",
		"svelte-highlight": "^7.7.0",
		"three": "^0.170.0"
	}
}

Solutions

I manage to fix this issue by remove by hands the exports property on the module's package.json.
I didn't found another way to fix it. I'm not a pro of configuring this file but is this property very important ? (When removing it I had no typing issues, but the module is function as well as it should)

---

Last thing :
I didn't found any issue like this one on Internet (forums, docs, ...)