[Bug]: Storybook couldn't evaluate your .storybook/main.ts file

[valentinpalkovic]

Describe the bug

Error message:

SB_CORE-SERVER_0007 (MainFileEvaluationError): Storybook couldn't evaluate your .storybook/main.ts file.
             Original error:
             Error: Transform failed with 1 error:
             (define name):1:0: ERROR: Expected identifier but found "import"

esbuild released a new version recently, containing a bug, affecting all Vite-based Storybooks.

Workaround

Pin the version of esbuild to the latest known working version, 0.24.0 (npm, pnpm):

// package.json
{
  "overrides": {
    "esbuild": "0.24.0"
  }
}

Use resolutions field in yarn projects:

// package.json
{
  "resolutions": {
    "esbuild": "0.24.0"
  }
}

[valentinpalkovic]

Related esbuild bug: evanw/esbuild#4010
fix: evanw/esbuild#4013

[yannbf]

This issue has been (esbuild downgraded) fixed in 8.5.0-beta.4 and will be fixed in 8.4.8, follow the release PR here: #29834

[yannbf]

Update, the maintainer of esbuild made a fix and will release a new version soon, so all you'll have to do is update your yarn lock once that happens.

[jmuzina]

Esbuild 0.24.2 has released and seems to have fixed this issue for me - update your lockfiles and you should be fine :)

[BretPehrsonWTW]

Confirmed that updating Esbuild from 0.24.1 to 0.24.2 fixed it for me.