Top Level Await of Modules with SSR

[milomg]

Describe the bug

In SSR, files seem to be collapsed into a single output file. However, this causes an issue with top level await because while promises would normally allow the rest of the file to be parsed and all top level variables to be defined, the browser immediately evaluates the promise and cannot get the value of the variable.

For example, consider the following code (this is roughly what you would expect await import("simple.js") to compile into)

console.log(await Promise.resolve().then(function () { return simple; }))
var simple = "hi"

The browser logs undefined, instead of the expected value of "hi".

This is important because using imports and top level await is a way to only import modules when in the browser and not on the server (or vice versa). For example, with SolidJS, I'm doing const mymodule = isServer ? await import ("server-module") : await import("client-stub")

Reproduction

https://stackblitz.com/edit/node-zgcsub

System Info

System:
    OS: macOS 11.6.1
    CPU: (8) x64 Intel(R) Core(TM) i7-6920HQ CPU @ 2.90GHz
    Memory: 86.71 MB / 16.00 GB
    Shell: 5.8 - /bin/zsh
  Binaries:
    Node: 17.7.1 - ~/.brew/bin/node
    Yarn: 1.22.17 - ~/.brew/bin/yarn
    npm: 8.5.4 - ~/.brew/bin/npm
  Browsers:
    Chrome: 99.0.4844.74
    Chrome Canary: 101.0.4948.0
    Firefox: 96.0.3
    Safari: 15.1
  npmPackages:
    vite: ^2.8.6 => 2.8.6

Used Package Manager

npm

Logs

No response

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Make sure this is a Vite issue and not a framework-specific issue. For example, if it's a Vue SFC related bug, it should likely be reported to https://github.com/vuejs/core instead.
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• The provided reproduction is a minimal reproducible example of the bug.

[sapphi-red]

Vite turns on inlineDynamicImports for SSR build.

vite/packages/vite/src/node/build.ts

Line 446 in 34df307

inlineDynamicImports: ssr && typeof input === 'string',

inlineDynamicImports changes execution order.
https://rollupjs.org/guide/en/#outputinlinedynamicimports
rollup/rollup#4166