Dynamically inserted importmap doesn't work in development mode

[sorin-davidoi]

Describe the bug

Inserting an importmap at runtime via a script statement in head does not work in development mode because the script that is inserting it is placed after the module import of @vite/client. This results in the following error:

An import map is added after module script load was triggered.

This issue only affects the development mode because it it caused by the presence of the @vite/client import.

Related issues:

• Vite inject "/@vite/client" script element above importmap element #9334 - the fix for this solved the issue by sorting the static importmap before the module scripts. It however doesn't take into account that classic scripts can dynamically insert importmaps.
• [Hard Issue] vite should not change importmap position in index.html #11304
• fix: importmap should insert before module preload link #11492
• [Hard Issue] vite should not change importmap position in index.html #11304

Workaround: trick Vite into thinking that the script that is inserting the importmap is an importmap itself - this will make sure that it gets sorted before the module import of @vite/client. This can be achieved by adding an attribute to it that matches this regular expression (e.g. data-vite-workaround="type=importmap").

Reproduction

https://stackblitz.com/edit/vitejs-vite-yde4az?file=index.html

Steps to reproduce

Run npm install && npm run dev.

Expected result:

• The page shows the text "Hello World!"

Actual result:

• The page shows the text "Waiting for script..."

Note that running npm install && npm run build && npm run preview works as expected.

System Info

Output from running the command in the linked StackBlitz:


System:
    OS: Linux 5.0 undefined
    CPU: (8) x64 Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz
    Memory: 0 Bytes / 0 Bytes
    Shell: 1.0 - /bin/jsh
  Binaries:
    Node: 18.18.0 - /usr/local/bin/node
    Yarn: 1.22.19 - /usr/local/bin/yarn
    npm: 9.4.2 - /usr/local/bin/npm
    pnpm: 8.10.5 - /usr/local/bin/pnpm
  npmPackages:
    vite: ^5.0.2 => 5.0.4

### Used Package Manager

npm

### Logs

_No response_

### Validations

- [X] Follow our [Code of Conduct](https://github.com/vitejs/vite/blob/main/CODE_OF_CONDUCT.md)
- [X] Read the [Contributing Guidelines](https://github.com/vitejs/vite/blob/main/CONTRIBUTING.md).
- [X] Read the [docs](https://vitejs.dev/guide).
- [X] Check that there isn't [already an issue](https://github.com/vitejs/vite/issues) that reports the same bug to avoid creating a duplicate.
- [X] 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 [vuejs/core](https://github.com/vuejs/core) instead.
- [X] Check that this is a concrete bug. For Q&A open a [GitHub Discussion](https://github.com/vitejs/vite/discussions) or join our [Discord Chat Server](https://chat.vitejs.dev/).
- [X] The provided reproduction is a [minimal reproducible example](https://stackoverflow.com/help/minimal-reproducible-example) of the bug.

[stackblitz]

Start a new pull request in StackBlitz Codeflow.

• vitejs-vite-yde4az (Open reproduction)

[HexaField]

@sorin-davidoi Would you be able to provide some more information about how to work around this?