[rathodkunj2005]

Closes #36399.

Summary

• Rewrite TypeScript extensions in static imports, re-exports, and string-literal dynamic imports during deno transpile (.ts/.tsx → .js, .mts → .mjs, .cts → .cjs).
• Preserve query/hash suffixes, declaration-file specifiers, non-TypeScript specifiers, and ordinary string literals.
• Add focused unit coverage for extension mapping and a spec regression covering static imports, re-exports, dynamic imports, and literal lookalikes.

Verification

• cargo check -p deno
• ./tools/format.js --check cli/tools/transpile.rs cli/tools/transpile/import_extensions.rs tests/specs/transpile/__test__.jsonc tests/specs/transpile/import_extensions.ts tests/specs/transpile/check_import_extensions.ts tests/specs/transpile/rewrite_import_extensions_emit.out
• rustc --edition=2024 --test cli/tools/transpile/import_extensions.rs -o /tmp/import_extensions_test && /tmp/import_extensions_test (2 passed)

AI assistance was used to investigate the issue and implement this change; I reviewed the resulting code and tests.

[bartlomieju]

Fixes #36399 and matches what the docs promise. The parse_module_with_post_process + VisitMut approach is the right hook, and clearing raw so the new value is what gets emitted is the easy thing to get wrong.

I pushed one fix: rewrite was matching on the extension alone, so it also rewrote specifiers that don't point at anything deno transpile emits — https://deno.land/x/foo/mod.ts became .../mod.js, and likewise for npm:/jsr:/bare/absolute specifiers. That turns a working import into a 404. It now only rewrites ./ and ../ specifiers, which is both what the docs describe ("./foo.ts → ./foo.js") and what tsc's rewriteRelativeImportExtensions does. Added unit coverage for the non-relative cases.

Two non-blocking nits:

• check_import_extensions.ts prints a single true/false, so a failure gives no clue which specifier didn't get rewritten. assertEquals on the emitted text, or a few asserts, would make CI failures diagnosable.
• The stray export {}; in the middle of that file isn't doing anything — the top-level await already makes it a module.

The test node_compat failure looks unrelated to this change. LGTM.

[rathodkunj2005]

Thanks — addressed both review comments in 182fbcf.

What changed:

• Added .jsx -> .js import specifier rewriting alongside the existing .tsx mapping.
• Handled TsImportEquals external module references such as import helper = require("./helper.cts").
• Extended the rewrite_import_extensions spec fixture to cover both cases.

Verification run locally:

• cargo fmt --check ✅
• git diff --check ✅
• cargo check -p deno --lib ✅
• cargo test --bin deno spec::transpile::rewrite_import_extensions was attempted, but the checkout ran out of disk space while compiling dependencies (No space left on device) before the test binary could finish building.

[rathodkunj2005]

Follow-up: fixed the formatter failure from the new view.jsx fixture in d9a6834 (missing trailing newline). Verified with:

• deno fmt --check cli/tools/transpile.rs cli/tools/transpile/import_extensions.rs tests/specs/transpile/__test__.jsonc tests/specs/transpile/check_import_extensions.ts tests/specs/transpile/import_extensions.ts tests/specs/transpile/view.jsx ✅
• cargo fmt --check ✅
• git diff --check ✅

[CLAassistant]

All committers have signed the CLA.