PR Checklist

Components defined directly inside a test spec file — e.g. a host component declared within a describe()/it()/beforeEach() callback to test a directive — threw ReferenceError: <Class> is not defined under fastCompile.

Closes #2360

Affected scope

• Primary scope: vite-plugin-angular
• Secondary scopes: none

Recommended merge strategy for maintainer [optional]

• Squash merge
• Rebase merge
• Other

What is the new behavior?

In test mode fastCompile uses the JIT path (angular-vite-plugin.ts sets jit to isTest when not explicitly provided), so jitTransform() runs rather than the AOT registry path.

jitTransform calls findAllClasses(), which walks the AST recursively and therefore finds classes nested inside function/callback scopes — including a host @Component declared inside a describe(...)/it(...) block, the common "host component to test a directive" pattern. For every such class it collected the generated metadata statements (<Class>.decorators = [...], _jitCompileComponent(<Class>, ...), <Class>.ctorParameters = ..., <Class>.propDecorators = ...) into a single array and appended them all at the end of the file (module scope). A class declared inside a callback is not in scope there, so the appended statement referenced an undefined name and threw ReferenceError: <Class> is not defined when the spec module was evaluated.

This was missed because the existing nested-class tests only asserted the emitted string contained <Class>.decorators — they never evaluated the code.

The fix emits each class's metadata statements directly after its class body via ms.appendLeft(node.end, ...), so they run in the class's own lexical scope:

• top-level classes → module scope (unchanged behavior)
• nested classes → the enclosing function/callback scope (now correct)

node.end is the position just past the class's closing brace (decorators were already stripped before node.start), so the statements land as the next statement(s) in the same block. A separate accumulator string preserves the existing post-loop detection of missing field-decorator imports. Angular's ɵcompileComponent installs a lazy ɵcmp, so emitting a top-level component's _jitCompileComponent(...) right after its own declaration (instead of after every class) is safe.

Before / after for a component declared inside a function:

// before — appended at end of file, TestComponent out of scope → ReferenceError
export function makeHost() {
  class TestComponent {}
  return TestComponent;
}
TestComponent.decorators = [...];          // ReferenceError
_jitCompileComponent(TestComponent, {...});

// after — emitted in scope
export function makeHost() {
  class TestComponent {}
  TestComponent.decorators = [...];
  _jitCompileComponent(TestComponent, {...});
  return TestComponent;
}

Test plan

• nx format:check (touched files)
• nx build vite-plugin-angular
• nx test vite-plugin-angular — 620 passed, 3 skipped
• Manual verification — confirmed against built output that the metadata statements are emitted inside the enclosing function scope

Adds an evaluating regression test (jit-transform.spec.ts) that runs the emitted JS through new Function with stubbed @angular/core exports — it would throw ReferenceError under the old file-end emit and passes with the fix.

Does this PR introduce a breaking change?

• Yes
• No

fastCompile is opt-in, and top-level class emit is unchanged — only the out-of-scope placement for nested classes is corrected.

Other information

Scoped to the JIT path, which is the path test mode uses, directly resolving the reported error. The AOT registry's .spec.ts handling in fast-compile-plugin.ts is not on the test path and is out of scope for this issue.

https://claude.ai/code/session_01DEPPXW9VMWVXNYmYDM2Y6A

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