Issues with some modules ?

Describe the bug When I import @ethersproject/bignumber in a page I get the following error when loading the page :

500
Cannot read property 'BN' of undefined

TypeError: Cannot read property 'BN' of undefined
    at ../src.ts/bignumber.ts:12:18
    at instantiateModule (C:\dev\wighawag\test-svelte-kit\node_modules\vite\dist\node\chunks\dep-6e02b235.js:69027:166)

Logs

browser :

GET http://localhost:3000/ 500 (Internal Server Error)

cli:

[vite] Error when evaluating SSR module /node_modules/@ethersproject/bignumber/lib.esm/bignumber.js:
TypeError: Cannot read property 'BN' of undefined
    at ../src.ts/bignumber.ts:12:18
    at instantiateModule (C:\dev\wighawag\test-svelte-kit\node_modules\vite\dist\node\chunks\dep-6e02b235.js:69027:166) (x3)

To Reproduce A repo created out of npm init svelte@next here : https://github.com/wighawag/test-svelte-kit

yarn && yarn dev

Expected behavior can import es module

Severity This is a blocker as I rely on @ethersproject packages

[benmccann]

Here’s an FAQ with tips for the standard solutions to loading packages in Vite: https://kit.svelte.dev/faq#how-do-i-fix-the-error-i-m-getting-trying-to-include-a-package

I’m not sure whether this is the same issue though

[GrygrFlzr]

This is a bug with Vite when bundling certain SSR dependencies and does not appear in a Vite template project because it does not perform SSR nor bundling.

You are correct that it should be in production dependencies, not dev dependencies, so that it can be bundled into the application. It looks like Vite is failing to see that @ethersproject/bignumber is referencing bn.js.

For a proper workaround that bundles the dependency into the application, do the following in svelte.config.cjs:

module.exports = {
  // ...
  kit: {
    // ...
    vite: {
      // ...
      optimizeDeps: {
        include: ['bn.js'],
      }
    }
  }
};