This allows lazily loading statically analyzable dynamic imports when not type checking:

// main.ts
console.error("Here");
await import("jsr:@david/code-block-writer");
console.error("Done");

Before:

> deno run main.ts
Download https://jsr.io/@david/code-block-writer/meta.json
Download https://jsr.io/@david/code-block-writer/13.0.3_meta.json
Download https://jsr.io/@david/code-block-writer/13.0.3/mod.ts
Download https://jsr.io/@david/code-block-writer/13.0.3/utils/string_utils.ts
Here
Done

After:

> deno run --unstable-lazy-dynamic-imports main.ts
Here
Download https://jsr.io/@david/code-block-writer/meta.json
Download https://jsr.io/@david/code-block-writer/13.0.3_meta.json
Download https://jsr.io/@david/code-block-writer/13.0.3/mod.ts
Download https://jsr.io/@david/code-block-writer/13.0.3/utils/string_utils.ts
Done

Enablement

Use --unstable-lazy-dynamic-imports or set "unstable": ["lazy-dynamic-imports"] in a deno.json.

Notes

1. Not loading them ahead of time means semver resolution may resolve differently because the order the dynamic imports get executed may differ from the order that's used without this flag.
2. deno run --check still loads these dynamic imports ahead of time because the information might be used for type checking.
3. This means your app may startup fine, but possibly fail loading a dynamic import due to a transient network error.

Closes #28581
Closes #23231 (this solution is easier than this and there is not much demand for that)
Ref #23149