Question 1

How do I use elm2nix with ParcelJS and Yarn?

Accepted Answer

As per the README FAQ, you need to create a custom `default.nix` derivation instead of using `elm2nix init`, with an example provided in a GitHub issue, requiring manual configuration for non-standard setups.

Question 2

elm2nix vs using Elm's package manager directly: which is better for reproducibility?

Accepted Answer

elm2nix excels in reproducibility by leveraging Nix's deterministic builds, but it adds complexity compared to Elm's native toolchain, which is simpler but less hermetic for cross-environment consistency.

Question 3

How to update Elm dependencies when using elm2nix?

Accepted Answer

After updating elm.json, run `elm2nix convert` to regenerate Nix expressions with new sha256 sums, then update the snapshot with `elm2nix snapshot` to reflect changes in the binary cache.

Question 4

Does elm2nix support the latest Elm version?

Accepted Answer

No, the README states it supports Elm 0.19.1, so it may not be compatible with newer Elm versions without updates to the tool, limiting its use for modern projects.

Question 5

How to integrate elm2nix into an existing Nix project?

Accepted Answer

Use the `elm2nix init` command to generate `default.nix`, then include it in your Nix expressions to handle Elm dependencies within your build environment, ensuring proper integration.

Question 6

What are the performance benefits of using elm2nix's snapshot feature?

Accepted Answer

The snapshot creates a binary cache (`registry.dat`) that speeds up builds by avoiding repeated downloads and calculations of Elm packages, especially beneficial in CI/CD systems for faster iterations.

elm2nix

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