Previously we defensively wrapped expressions in case they ran afoul of
precedence rules. For example, it would be easy to create the TS AST structure
Call(Ternary(a, b, c)), but might result in printed code of:
```
a ? b : c()
```
Whereas the actual structure we meant to generate is:
```
(a ? b : c)()
```
However the TypeScript renderer appears to be clever enough to provide
parenthesis as necessary.
This commit removes these defensive paraenthesis in the cases of binary
and ternary operations.
FW-1273
PR Close#30349
Previously we were using an anonymous type `{specifier: string; qualifier: string;}`
throughout the code base. This commit gives this type a name and ensures it
is only defined in one place.
PR Close#25445
This fixes an issue with commit b6f6b117. In this commit, default imports
processed in a type-to-value conversion were recorded as non-local imports
with a '*' name, and the ImportManager generated a new default import for
them. When transpiled to ES2015 modules, this resulted in the following
correct code:
import i3 from './module';
// somewhere in the file, a value reference of i3:
{type: i3}
However, when the AST with this synthetic import and reference was
transpiled to non-ES2015 modules (for example, to commonjs) an issue
appeared:
var module_1 = require('./module');
{type: i3}
TypeScript renames the imported identifier from i3 to module_1, but doesn't
substitute later references to i3. This is because the import and reference
are both synthetic, and never went through the TypeScript AST step of
"binding" which associates the reference to its import. This association is
important during emit when the identifiers might change.
Synthetic (transformer-added) imports will never be bound properly. The only
possible solution is to reuse the user's original import and the identifier
from it, which will be properly downleveled. The issue with this approach
(which prompted the fix in b6f6b117) is that if the import is only used in a
type position, TypeScript will mark it for deletion in the generated JS,
even though additional non-type usages are added in the transformer. This
again would leave a dangling import.
To work around this, it's necessary for the compiler to keep track of
identifiers that it emits which came from default imports, and tell TS not
to remove those imports during transpilation. A `DefaultImportTracker` class
is implemented to perform this tracking. It implements a
`DefaultImportRecorder` interface, which is used to record two significant
pieces of information:
* when a WrappedNodeExpr is generated which refers to a default imported
value, the ts.Identifier is associated to the ts.ImportDeclaration via
the recorder.
* when that WrappedNodeExpr is later emitted as part of the statement /
expression translators, the fact that the ts.Identifier was used is
also recorded.
Combined, this tracking gives the `DefaultImportTracker` enough information
to implement another TS transformer, which can recognize default imports
which were used in the output of the Ivy transform and can prevent them
from being elided. This is done by creating a new ts.ImportDeclaration for
the imports with the same ts.ImportClause. A test verifies that this works.
PR Close#29266
This commit refactors and expands ngtsc's support for generating imports of
values from imports of types (this is used for example when importing a
class referenced in a type annotation in a constructor).
Previously, this logic handled "import {Foo} from" and "import * as foo
from" style imports, but failed on imports of default values ("import
Foo from"). This commit moves the type-to-value logic to a separate file and
expands it to cover the default import case. Doing this also required
augmenting the ImportManager to track default as well as non-default import
generation. The APIs were made a little cleaner at the same time.
PR Close#29146
In the past, @Injectable had no side effects and existing Angular code is
therefore littered with @Injectable usage on classes which are not intended
to be injected.
A common example is:
@Injectable()
class Foo {
constructor(private notInjectable: string) {}
}
and somewhere else:
providers: [{provide: Foo, useFactory: ...})
Here, there is no need for Foo to be injectable - indeed, it's impossible
for the DI system to create an instance of it, as it has a non-injectable
constructor. The provider configures a factory for the DI system to be
able to create instances of Foo.
Adding @Injectable in Ivy signifies that the class's own constructor, and
not a provider, determines how the class will be created.
This commit adds logic to compile classes which are marked with @Injectable
but are otherwise not injectable, and create an ngInjectableDef field with
a factory function that throws an error. This way, existing code in the wild
continues to compile, but if someone attempts to use the injectable it will
fail with a useful error message.
In the case where strictInjectionParameters is set to true, a compile-time
error is thrown instead of the runtime error, as ngtsc has enough
information to determine when injection couldn't possibly be valid.
PR Close#28523
Translation of WriteKeyExpr expressions was not implemented in the ngtsc
expression translator. This resulted in binding expressions like
"target[key] = $event" not compiling.
This commit fixes the bug by implementing WriteKeyExpr translation.
PR Close#28523
During analysis, the `ComponentDecoratorHandler` passes the component
template to the `parseTemplate()` function. Previously, there was little or
no information about the original source file, where the template is found,
passed when calling this function.
Now, we correctly compute the URL of the source of the template, both
for external `templateUrl` and in-line `template` cases. Further in the
in-line template case we compute the character range of the template
in its containing source file; *but only in the case that the template is
a simple string literal*. If the template is actually a dynamic value like
an interpolated string or a function call, then we do not try to add the
originating source file information.
The translator that converts Ivy AST nodes to TypeScript now adds these
template specific source mappings, which account for the file where
the template was found, to the templates to support stepping through the
template creation and update code when debugging an Angular application.
Note that some versions of TypeScript have a bug which means they cannot
support external template source-maps. We check for this via the
`canSourceMapExternalTemplates()` helper function and avoid trying to
add template mappings to external templates if not supported.
PR Close#28055
The TypeTranslatorVisitor visitor returned strings because before it wasn't possible to transform declaration files directly through the TypeScript custom transformer API.
Now that's possible though, so it should return nodes instead.
PR Close#28342
Currently the ImportManager class handles various rewriting actions of
imports when compiling @angular/core. This is required as code compiled
within @angular/core cannot import from '@angular/core'. To work around
this, imports are rewritten to get core symbols from a particular file,
r3_symbols.ts.
In this refactoring, this rewriting logic is moved out of the ImportManager
and put behind an interface, ImportRewriter. There are three implementers
of the interface:
* NoopImportRewriter, used for compiling all non-core packages.
* R3SymbolsImportRewriter, used when ngtsc compiles @angular/core.
* NgccFlatImportRewriter, used when ngcc compiles @angular/core (special
logic is needed because ngcc has to rewrite imports in flat bundles
differently than in non-flat bundles).
This is a precursor to using this rewriting logic in other contexts besides
the ImportManager.
PR Close#27998
If a template contains specific TypeScript syntax, such as a non-null
assertion, the code that is emitted from ngcc into a JavaScript bundle
should not retain such syntax as it is invalid in JS.
A full-blown TypeScript emit of a complete ts.SourceFile would be
required to be able to emit JS and possibly downlevel into a lower
language target, which is not an option for ngcc as it currently
operates on partial ASTs, not full source files.
Instead, ngtsc no longer produces TypeScript specific syntax in the first
place, such that TypeScript print logic will only generate JS code.
PR Close#27051
When ngtsc compiles @angular/core, it rewrites core imports to the
r3_symbols.ts file that exposes all internal symbols under their
external name. When creating the FESM bundle, the r3_symbols.ts file
causes the external symbol names to be rewritten to their internal name.
Under ngcc compilations of FESM bundles, the indirection of
r3_symbols.ts is no longer in place such that the external names are
retained in the bundle. Previously, the external name `ɵdefineNgModule`
was explicitly declared internally to resolve this issue, but the
recently added `setClassMetadata` was not declared as such, causing
runtime errors.
Instead of relying on the r3_symbols.ts file to perform the rewrite of
the external modules to their internal variants, the translation is
moved into the `ImportManager` during the compilation itself. This
avoids the need for providing the external name manually.
PR Close#27055
This commit introduces the setClassMetadata() private function, which
adds metadata to a type in a way that can be accessed via Angular's
ReflectionCapabilities. Currently, it writes to static fields as if
the metadata being added was downleveled from decorators by tsickle.
The plan is for ngtsc to emit code which calls this function, passing
metadata on to the runtime for testing purposes. Calls to this function
would then be tree-shaken away for production bundles.
Testing strategy: proper operation of this function will be an integral
part of TestBed metadata overriding. Angular core tests will fail if this
is broken.
PR Close#26860
Uglify and other tree-shakers attempt to determine if the invocation
of a function is side-effectful, and remove it if so (and the result
is unused). A /*@__PURE__*/ annotation on the call site can be used
to hint to the optimizer that the invocation has no side effects and
is safe to tree-shake away.
This commit adds a 'pure' flag to the output AST function call node,
which can be used to signal to downstream emitters that a pure
annotation should be added. It also modifies ngtsc's emitter to
emit an Uglify pure annotation when this flag is set.
Testing strategy: this will be tested via its consumers, by asserting
that pure functions are translated with the correct comment.
PR Close#26860
Template type-checking will make use of expression and statement
translation as well as the ImportManager, so this code needs to
live in a separate build target which can be depended on by both
the main ngtsc transform as well as the template type-checking
mechanism. This refactor introduces a separate build target
for that code.
PR Close#26203
