This commit causes imports added by ngtsc's `ImportManager` to have their
TypeScript "original node" set to the generated `ts.ImportDeclaration`
statement.
In g3, the tsickle transformer runs after the Angular transformer and post-
processes Angular's compilation output. One of its post-processing tasks is
to transform generated imports and references to imported symbols from the
commonjs module system to the g3 module system. Part of this transformation
involves recognizing modules with specific metadata and altering references
to symbols from those modules accordingly.
Normally, tsickle can rely on TypeScript's binding for an imported symbol to
find its origin module and thus the correct metadata for the symbol. However
the Angular transform generates new synthetic imports which don't have such
binding information. Angular's imports are always namespace imports of the
form:
```
import * as qualifier 'module/specifier';
```
References to such an import are then of the form `qualifier.SymbolName`.
To process such imports properly, tsickle needs to be able to associate the
reference to `qualifier` in the expression `qualifer.SymbolName` with the
`ts.ImportDeclaration` statement that defines it. It expects to do this by
looking at the `ts.getOriginalNode()` for the `qualifier` reference, which
should be the `ts.ImportDeclaration`. This commit changes ngtsc's import
generation mechanism to set the original node on `qualifier` identifiers
according to this expectation.
This commit is not tested in the direct compiler tests, since:
1) there is no observable behavior externally from setting the original node
2) we don't have tests that intercept transformer operations (which could be
used to directly assert against the AST nodes)
3) tsickle's published version does not (yet) contain the g3-specific
transformations which rely on the original node and would thus allow the
behavior to be observed.
Instead, we rely on the g3 testing suite to validate the correctness of this
fix. Breaking this functionality would cause g3 compilation errors for
targets, since tsickle would be unable to transform imports correctly.
PR Close#40711
Previously the value passed to `AstFactory.attachComments()` could be
`undefined` which is counterintuitive, since why attach something that
doesn't exist? Now it expects there to be a defined array. Further it no
longer returns a statement. Both these aspects of the interface were designed
to make the usage simpler but has the result of complicating the implemenation.
The `ExpressionTranslatorVisitor` now has a helper function (`attachComments()`)
to handle `leadingComments` being undefined and also returning the statement.
This keeps the usage in the translator simple, while ensuring that the `AstFactory`
API is not influenced by how it is used.
PR Close#39076
This commit adds the `AstHost` interface, along with implementations for
both Babel and TS.
It also implements the Babel vesion of the `AstFactory` interface, along
with a linker specific implementation of the `ImportGenerator` interface.
These classes will be used by the new "ng-linker" to transform prelinked
library code using a Babel plugin.
PR Close#38866
The `AstFactory.createFunctionDeclaration()` was allowing `null` to be
passed as the function `name` value. This is not actually possible, since
function declarations must always have a name.
PR Close#38866
This commit refactors the `ExpressionTranslatorVisitor` so that it
is not tied directly to the TypeScript AST. Instead it uses generic
`TExpression` and `TStatement` types that are then converted
to concrete types by the `TypeScriptAstFactory`.
This paves the way for a `BabelAstFactory` that can be used to
generate Babel AST nodes instead of TypeScript, which will be
part of the new linker tool.
PR Close#38775
