Error when loading date-fns dependency: Cannot read property 'default' of null

Describe the bug

I’m using Svelte Kit and Kit uses Vite. After the first start of the project, and the first time visiting the localhost:3000, in the kit console it throws the below log. After second start of project, it doesn’t throw any error. Also, if you delete .svelte and node_modules folders, then start project, it will again throw errors.

Reproduction

I have a public repo for this:

https://github.com/kahverengi001/vite-reproduction-bug-date-fns

System Info

Output of npx envinfo --system --npmPackages vite,@vitejs/plugin-vue --binaries --browsers:

❯ npx envinfo --system --npmPackages vite,@vitejs/plugin-vue --binaries --browsers

  System:
    OS: Linux 5.10 Arch Linux
    CPU: (8) x64 Intel(R) Core(TM) i7-4720HQ CPU @ 2.60GHz
    Memory: 280.51 MB / 15.54 GB
    Container: Yes
    Shell: 5.8 - /bin/zsh
  Binaries:
    Node: 15.14.0 - /usr/bin/node
    Yarn: 1.22.10 - /usr/bin/yarn
    npm: 7.10.0 - /usr/bin/npm
  Browsers:
    Chromium: 90.0.4430.72
    Firefox: 87.0
  npmPackages:
    vite: ^2.1.0 => 2.1.5 

Used package manager: npm/yarn

Logs

❯ yarn dev
yarn run v1.22.10
$ svelte-kit dev

  SvelteKit v1.0.0-next.83

  local:   http://localhost:3000
  network: not exposed
  network: not exposed
  network: not exposed
  network: not exposed

  Use --host to expose server to other devices on this network


11:24:33 AM [vite] new dependencies found: date-fns, updating...
11:24:34 AM [vite] ✨ dependencies updated, reloading page...
Cannot read property 'default' of null
TypeError: Cannot read property 'default' of null
    at eval (/src/lib/Header/index.svelte:24:223)
    at Object.$$render (/home/kahverengi/vite-reproduction-bug-date-fns/node_modules/svelte/internal/index.js:1369:22)
    at eval (/home/kahverengi/vite-reproduction-bug-date-fns/src/routes/$layout.svelte:20:94)
    at Object.$$render (/home/kahverengi/vite-reproduction-bug-date-fns/node_modules/svelte/internal/index.js:1369:22)
    at eval (//home/kahverengi/vite-reproduction-bug-date-fns/.svelte/dev/generated/root.svelte:55:122)
    at $$render (/home/kahverengi/vite-reproduction-bug-date-fns/node_modules/svelte/internal/index.js:1369:22)
    at Object.render (/home/kahverengi/vite-reproduction-bug-date-fns/node_modules/svelte/internal/index.js:1377:26)
    at render_response (file:///home/kahverengi/vite-reproduction-bug-date-fns/node_modules/@sveltejs/kit/dist/ssr.js:364:28)
    at async respond (file:///home/kahverengi/vite-reproduction-bug-date-fns/node_modules/@sveltejs/kit/dist/ssr.js:1110:10)
    at async render_page (file:///home/kahverengi/vite-reproduction-bug-date-fns/node_modules/@sveltejs/kit/dist/ssr.js:1154:20)

Additional Context There is also a tracking current issue in Svelte Kit repo: https://github.com/sveltejs/kit/issues/1111

[mcmxcdev]

I am also using date-fns in my SvelteKit project, try to move the library to devDependencies in package.json Should fix your problem 😉

[Niputi]

removing this part from authors reproduction in svelte.config.cjs makes date-fns work

vite: {
	ssr: {
		noExternal: Object.keys(pkg.dependencies || {})
	}
}

npmPackages: @sveltejs/adapter-node: next => 1.0.0-next.16 @sveltejs/kit: next => 1.0.0-next.83 vite: ^2.1.0 => 2.1.5