xi18n is the operation of extracting i18n messages from templates in the
compilation. Previously, only View Engine was able to perform xi18n. This
commit implements xi18n in the Ivy compiler, and a copy of the View Engine
test for Ivy verifies that the results are identical.
PR Close#42485
The `emitDecoratorMetadata` compiler option does not have to be enabled
as Angular decorators are transformed by the AOT compiler. Having the
option enabled in our tests can hide issues around import preservation,
as with `emitDecoratorMetadata` enabled the TypeScript compiler itself
does not elide imports even if they are only used in type-positions.
This is unlike having `emitDecoratorMetadata` disabled, however; in that
case the Angular compiler has to actively trick TypeScript into
retaining default imports when an identifier in a type-only position has
been reified into a value position for DI purposes.
A subsequent commit addresses a bug in default import preservation
that relies on this flag being `false`.
PR Close#41557
In Angular programs, changing a file may require other files to be
emitted as well due to implicit NgModule dependencies. For example, if
the selector of a directive is changed then all components that have
that directive in their compilation scope need to be recompiled, as the
change of selector may affect the directive matching results.
Until now, the compiler solved this problem using a single dependency
graph. The implicit NgModule dependencies were represented in this
graph, such that a changed file would correctly also cause other files
to be re-emitted. This approach is limited in a few ways:
1. The file dependency graph is used to determine whether it is safe to
reuse the analysis data of an Angular decorated class. This analysis
data is invariant to unrelated changes to the NgModule scope, but
because the single dependency graph also tracked the implicit
NgModule dependencies the compiler had to consider analysis data as
stale far more often than necessary.
2. It is typical for a change to e.g. a directive to not affect its
public API—its selector, inputs, outputs, or exportAs clause—in which
case there is no need to re-emit all declarations in scope, as their
compilation output wouldn't have changed.
This commit implements a mechanism by which the compiler is able to
determine the impact of a change by comparing it to the prior
compilation. To achieve this, a new graph is maintained that tracks all
public API information of all Angular decorated symbols. During an
incremental compilation this information is compared to the information
that was captured in the most recently succeeded compilation. This
determines the exact impact of the changes to the public API, which
is then used to determine which files need to be re-emitted.
Note that the file dependency graph remains, as it is still used to
track the dependencies of analysis data. This graph does no longer track
the implicit NgModule dependencies, which allows for better reuse of
analysis data.
These changes also fix a bug where template type-checking would fail to
incorporate changes made to a transitive base class of a
directive/component. This used to be a problem because transitive base
classes were not recorded as a transitive dependency in the file
dependency graph, such that prior type-check blocks would erroneously
be reused.
This commit also fixes an incorrectness where a change to a declaration
in NgModule `A` would not cause the declarations in NgModules that
import from NgModule `A` to be re-emitted. This was intentionally
incorrect as otherwise the performance of incremental rebuilds would
have been far worse. This is no longer a concern, as the compiler is now
able to only re-emit when actually necessary.
Fixes#34867Fixes#40635Closes#40728
PR Close#40947
A couple reasons to justify removing the flag:
* It adds code to the compiler that is only meant to support test cases
and not any production. We should avoid code in that's only
meant to support tests.
* The flag enables writing tests that do not mimic real-world behavior
because they allow invalid applications
PR Close#40013
The newly built compliance test runner was not using the shared source
file cache that was added in b627f7f02e,
which offers a significant performance boost to the compliance test
targets.
PR Close#39956
ngtsc has a robust suite of testing utilities, designed for in-memory
testing of a TypeScript compiler. Previously these utilities lived in the
`test` directory for the compiler-cli package.
This commit moves those utilities to an `ngtsc/testing` package, enabling
them to be depended on separately and opening the door for using them from
the upcoming language server testing infrastructure.
As part of this refactoring, the `fake_core` package (a lightweight API
replacement for @angular/core) is expanded to include functionality needed
for Language Service test use cases.
PR Close#39594
Previously the `ConcreteDeclaration` and `InlineDeclaration` had
different properties for the underlying node type. And the `InlineDeclaration`
did not store a value that represented its declaration.
It turns out that a natural declaration node for an inline type is the
expression. For example in UMD/CommonJS this would be the `exports.<name>`
property access node.
So this expression is now used for the `node` of `InlineDeclaration` types
and the `expression` property is dropped.
To support this the codebase has been refactored to use a new `DeclarationNode`
type which is a union of `ts.Declaration|ts.Expression` instead of `ts.Declaration`
throughout.
PR Close#38959
Some compiler tests take a long time to run, even using multiple
executors. A profiling session revealed that most time is spent in
parsing source files, especially the default libraries are expensive to
parse.
The default library files are constant across all tests, so this commit
introduces a shared cache of parsed source files of the default
libraries. This achieves a significant improvement for several targets
on my machine:
//packages/compiler-cli/test/compliance: from 23s to 5s.
//packages/compiler-cli/test/ngtsc: from 115s to 11s.
Note that the number of shards for the compliance tests has been halved,
as the extra shards no longer provide any speedup.
PR Close#38909
The `fs.relative()` method assumed that the file-system is a single tree,
which is not the case in Windows, where you can have multiple drives,
e.g. `C:`, `D:` etc.
This commit changes `fs.relative()` so that it no longer forces the result
to be a `PathSegment` and then flows that refactoring through the rest of
the compiler-cli (and ngcc). The main difference is that now, in some cases,
we needed to check whether the result is "rooted", i.e an `AbsoluteFsPath`,
rather than a `PathSegment`, before using it.
Fixes#36777
PR Close#37959
Commit 4213e8d5 introduced shim reference tagging into the compiler, and
changed how the `TypeCheckProgramHost` worked under the hood during the
creation of a template type-checking program. This work enabled a more
incremental flow for template type-checking, but unintentionally introduced
several regressions in performance, caused by poor incrementality during
`ts.Program` creation.
1. The `TypeCheckProgramHost` was made to rely on the `ts.CompilerHost` to
retrieve instances of `ts.SourceFile`s from the original program. If the
host does not return the original instance of such files, but instead
creates new instances, this has two negative effects: it incurs
additional parsing time, and it interferes with TypeScript's ability to
reuse information about such files.
2. During the incremental creation of a `ts.Program`, TypeScript compares
the `referencedFiles` of `ts.SourceFile` instances from the old program
with those in the new program. If these arrays differ, TypeScript cannot
fully reuse the old program. The implementation of reference tagging
introduced in 4213e8d5 restores the original `referencedFiles` array
after a `ts.Program` is created, which means that future incremental
operations involving that program will always fail this comparison,
effectively limiting the incrementality TypeScript can achieve.
Problem 1 exacerbates problem 2: if a new `ts.SourceFile` is created by the
host after shim generation has been disabled, it will have an untagged
`referencedFiles` array even if the original file's `referencedFiles` was
not restored, triggering problem 2 when creating the template type-checking
program.
To fix these issues, `referencedFiles` arrays are now restored on the old
`ts.Program` prior to the creation of a new incremental program. This allows
TypeScript to get the most out of reusing the old program's data.
Additionally, the `TypeCheckProgramHost` now uses the original `ts.Program`
to retrieve original instances of `ts.SourceFile`s where possible,
preventing issues when a host would otherwise return fresh instances.
Together, these fixes ensure that program reuse is as incremental as
possible, and tests have been added to verify this for certain scenarios.
An optimization was further added to prevent the creation of a type-checking
`ts.Program` in the first place if no type-checking is necessary.
PR Close#37641
Some projects include .js source files (via the TypeScript allowJs option).
Previously, the compiler would attempt to tag these files for shims, which
caused errors as the regex used to create shim filenames assumes a .ts file.
This commit fixes the bug by filtering out non-ts files during tagging.
PR Close#36987
As a performance optimization, this commit splits the single
__ngtypecheck__.ts file which was previously added to the user's program as
a container for all template type-checking code into multiple .ngtypecheck
shim files, one for each original file in the user's program.
In larger applications, the generation, parsing, and checking of this single
type-checking file was a huge performance bottleneck, with the file often
exceeding 1 MB in text content. Particularly in incremental builds,
regenerating this single file for the entire application proved especially
expensive.
This commit introduces a new strategy for template type-checking code which
makes use of a new interface, the `TypeCheckingProgramStrategy`. This
interface abstracts the process of creating a new `ts.Program` to type-check
a particular compilation, and allows the mechanism there to be kept separate
from the more complex logic around dealing with multiple .ngtypecheck files.
A new `TemplateTypeChecker` hosts that logic and interacts with the
`TypeCheckingProgramStrategy` to actually generate and return diagnostics.
The `TypeCheckContext` class, previously the workhorse of template type-
checking, is now solely focused on collecting and generating type-checking
file contents.
A side effect of implementing the new `TypeCheckingProgramStrategy` in this
way is that the API is designed to be suitable for use by the Angular
Language Service as well. The LS also needs to type-check components, but
has its own method for constructing a `ts.Program` with type-checking code.
Note that this commit does not make the actual checking of templates at all
_incremental_ just yet. That will happen in a future commit.
PR Close#36211
Shim generation was built on a lie.
Shims are files added to the program which aren't original files authored by
the user, but files authored effectively by the compiler. These fall into
two categories: files which will be generated (like the .ngfactory shims we
generate for View Engine compatibility) as well as files used internally in
compilation (like the __ng_typecheck__.ts file).
Previously, shim generation was driven by the `rootFiles` passed to the
compiler as input. These are effectively the `files` listed in the
`tsconfig.json`. Each shim generator (e.g. the `FactoryGenerator`) would
examine the `rootFiles` and produce a list of shim file names which it would
be responsible for generating. These names would then be added to the
`rootFiles` when the program was created.
The fatal flaw here is that `rootFiles` does not always account for all of
the files in the program. In fact, it's quite rare that it does. Users don't
typically specify every file directly in `files`. Instead, they rely on
TypeScript, during program creation, starting with a few root files and
transitively discovering all of the files in the program.
This happens, however, during `ts.createProgram`, which is too late to add
new files to the `rootFiles` list.
As a result, shim generation was only including shims for files actually
listed in the `tsconfig.json` file, and not for the transitive set of files
in the user's program as it should.
This commit completely rewrites shim generation to use a different technique
for adding files to the program, inspired by View Engine's shim generator.
In this new technique, as the program is being created and `ts.SourceFile`s
are being requested from the `NgCompilerHost`, shims for those files are
generated and a reference to them is patched onto the original file's
`ts.SourceFile.referencedFiles`. This causes TS to think that the original
file references the shim, and causes the shim to be included in the program.
The original `referencedFiles` array is saved and restored after program
creation, hiding this little hack from the rest of the system.
The new shim generation engine differentiates between two kinds of shims:
top-level shims (such as the flat module entrypoint file and
__ng_typecheck__.ts) and per-file shims such as ngfactory or ngsummary
files. The former are included via `rootFiles` as before, the latter are
included via the `referencedFiles` of their corresponding original files.
As a result of this change, shims are now correctly generated for all files
in the program, not just the ones named in `tsconfig.json`.
A few mitigating factors prevented this bug from being realized until now:
* in g3, `files` does include the transitive closure of files in the program
* in CLI apps, shims are not really used
This change also makes use of a novel technique for associating information
with source files: the use of an `NgExtension` `Symbol` to patch the
information directly onto the AST object. This is used in several
circumstances:
* For shims, metadata about a `ts.SourceFile`'s status as a shim and its
origins are held in the extension data.
* For original files, the original `referencedFiles` are stashed in the
extension data for later restoration.
The main benefit of this technique is a lot less bookkeeping around `Map`s
of `ts.SourceFile`s to various kinds of data, which need to be tracked/
invalidated as part of incremental builds.
This technique is based on designs used internally in the TypeScript
compiler and is serving as a prototype of this design in ngtsc. If it works
well, it could have benefits across the rest of the compiler.
PR Close#36211
FileToModuleHost aliasing supports compilation within environments that have
two properties:
1. A `FileToModuleHost` exists which defines canonical module names for any
given TS file.
2. Dependency restrictions exist which prevent the import of arbitrary files
even if such files are within the .d.ts transitive closure of a
compilation ("strictdeps").
In such an environment, generated imports can only go through import paths
which are already present in the user program. The aliasing system supports
the generation and consumption of such imports at runtime.
`FileToModuleHost` aliasing does not emit re-exports in .d.ts files. This
means that it's safe to rely on alias re-exports in generated .js code (they
are guaranteed to exist at runtime) but not in template type-checking code
(since TS will not be able to follow such imports). Therefore, non-aliased
imports should be used in template type-checking code.
This commit adds a `NoAliasing` flag to `ImportFlags` and sets it when
generating imports in template type-checking code. The testing environment
is also patched to support resolution of FileToModuleHost canonical paths
within the template type-checking program, enabling testing of this change.
PR Close#34649
This commit adds the ability to change directories using the compiler's
internal filesystem abstraction. This is a prerequisite for writing tests
which are sensitive to the current working directory.
In addition to supporting the `chdir()` operation, this commit also fixes
`getDefaultLibLocation()` for mock filesystems to not assume `node_modules`
is in the current directory, but to resolve it similarly to how Node does
by progressively looking higher in the directory tree.
PR Close#33828
These exports are no longer used by the CLI since 7.1.0. Since major versions of the CLI are now locked to major versions of the framework, a CLI user will not be able to use FW 9.0+ on an outdated version (<7.1.0) of the CLI that uses these old APIs.
PR Close#33242
Prior to this change, the template source mapping details were always
built during the analysis phase, under the assumption that pre-analysed
templates would always correspond with external templates. This has
turned out to be a false assumption, as inline templates are also
pre-analyzed to be able to preload any stylesheets included in the
template.
This commit fixes the bug by capturing the template source mapping
details at the moment the template is parsed, which is either during the
preanalysis phase when preloading is available, or during the analysis
phase when preloading is not supported.
Tests have been added to exercise the template error mapping in
asynchronous compilations where preloading is enabled, similar to how
the CLI performs compilations.
Fixes#32538
PR Close#32544
In ngc is was valid to set the "flatModuleOutFile" option to "null". This is sometimes
necessary if a tsconfig extends from another one but the "fatModuleOutFile" option
needs to be unset (note that "undefined" does not exist as value in JSON)
Now if ngtsc is used to compile the project, ngtsc will fail with an error because it
tries to do string manipulation on the "flatModuleOutFile". This happens because
ngtsc only skips flat module indices if the option is set to "undefined".
Since this is not compatible with what was supported in ngc and such exceptions
should be avoided, the flat module check is now aligned with ngc.
```
TypeError: Cannot read property 'replace' of null
at Object.normalizeSeparators (/home/circleci/project/node_modules/@angular/compiler-cli/src/ngtsc/util/src/path.js:35:21)
at new NgtscProgram (/home/circleci/project/node_modules/@angular/compiler-cli/src/ngtsc/program.js:126:52)
```
Additionally setting the `flatModuleOutFile` option to an empty string
currently results in unexpected behavior. No errors is thrown, but the
flat module index file will be `.ts` (no file name; just extension).
This is now also fixed by treating an empty string similarly to
`null`.
PR Close#32235
Historically, the Angular Compiler has produced both native TypeScript
diagnostics (called ts.Diagnostics) and its own internal Diagnostic format
(called an api.Diagnostic). This was done because TypeScript ts.Diagnostics
cannot be produced for files not in the ts.Program, and template type-
checking diagnostics are naturally produced for external .html template
files.
This design isn't optimal for several reasons:
1) Downstream tooling (such as the CLI) must support multiple formats of
diagnostics, adding to the maintenance burden.
2) ts.Diagnostics have gotten a lot better in recent releases, with support
for suggested changes, highlighting of the code in question, etc. None of
these changes have been of any benefit for api.Diagnostics, which have
continued to be reported in a very primitive fashion.
3) A future plugin model will not support anything but ts.Diagnostics, so
generating api.Diagnostics is a blocker for ngtsc-as-a-plugin.
4) The split complicates both the typings and the testing of ngtsc.
To fix this issue, this commit changes template type-checking to produce
ts.Diagnostics instead. Instead of reporting a special kind of diagnostic
for external template files, errors in a template are always reported in
a ts.Diagnostic that highlights the portion of the template which contains
the error. When this template text is distinct from the source .ts file
(for example, when the template is parsed from an external resource file),
additional contextual information links the error back to the originating
component.
A template error can thus be reported in 3 separate ways, depending on how
the template was configured:
1) For inline template strings which can be directly mapped to offsets in
the TS code, ts.Diagnostics point to real ranges in the source.
This is the case if an inline template is used with a string literal or a
"no-substitution" string. For example:
```typescript
@Component({..., template: `
<p>Bar: {{baz}}</p>
`})
export class TestCmp {
bar: string;
}
```
The above template contains an error (no 'baz' property of `TestCmp`). The
error produced by TS will look like:
```
<p>Bar: {{baz}}</p>
~~~
test.ts:2:11 - error TS2339: Property 'baz' does not exist on type 'TestCmp'. Did you mean 'bar'?
```
2) For template strings which cannot be directly mapped to offsets in the
TS code, a logical offset into the template string will be included in
the error message. For example:
```typescript
const SOME_TEMPLATE = '<p>Bar: {{baz}}</p>';
@Component({..., template: SOME_TEMPLATE})
export class TestCmp {
bar: string;
}
```
Because the template is a reference to another variable and is not an
inline string constant, the compiler will not be able to use "absolute"
positions when parsing the template. As a result, errors will report logical
offsets into the template string:
```
<p>Bar: {{baz}}</p>
~~~
test.ts (TestCmp template):2:15 - error TS2339: Property 'baz' does not exist on type 'TestCmp'.
test.ts:3:28
@Component({..., template: TEMPLATE})
~~~~~~~~
Error occurs in the template of component TestCmp.
```
This error message uses logical offsets into the template string, and also
gives a reference to the `TEMPLATE` expression from which the template was
parsed. This helps in locating the component which contains the error.
3) For external templates (templateUrl), the error message is delivered
within the HTML template file (testcmp.html) instead, and additional
information contextualizes the error on the templateUrl expression from
which the template file was determined:
```
<p>Bar: {{baz}}</p>
~~~
testcmp.html:2:15 - error TS2339: Property 'baz' does not exist on type 'TestCmp'.
test.ts:10:31
@Component({..., templateUrl: './testcmp.html'})
~~~~~~~~~~~~~~~~
Error occurs in the template of component TestCmp.
```
PR Close#31952
Versions of CLI prior to angular/angular-cli@0e339ee did not expose the host.getModifiedResourceFiles() method.
This meant that null was being passed through to the IncrementalState.reconcile() method
to indicate that there were either no changes or the host didn't support that method.
This commit fixes a bug where we were checking for undefined rather than null when
deciding whether any resource files had changed, causing a null reference error to be thrown.
This bug was not caught by the unit testing because the tests set up the changed files
via a slightly different process, not having access to the CompilerHost, and these test
were making the erroneous assumption that undefined indicated that there were no
changed files.
PR Close#31322
To improve cross platform support, all file access (and path manipulation)
is now done through a well known interface (`FileSystem`).
For testing a number of `MockFileSystem` implementations are provided.
These provide an in-memory file-system which emulates operating systems
like OS/X, Unix and Windows.
The current file system is always available via the static method,
`FileSystem.getFileSystem()`. This is also used by a number of static
methods on `AbsoluteFsPath` and `PathSegment`, to avoid having to pass
`FileSystem` objects around all the time. The result of this is that one
must be careful to ensure that the file-system has been initialized before
using any of these static methods. To prevent this happening accidentally
the current file system always starts out as an instance of `InvalidFileSystem`,
which will throw an error if any of its methods are called.
You can set the current file-system by calling `FileSystem.setFileSystem()`.
During testing you can call the helper function `initMockFileSystem(os)`
which takes a string name of the OS to emulate, and will also monkey-patch
aspects of the TypeScript library to ensure that TS is also using the
current file-system.
Finally there is the `NgtscCompilerHost` to be used for any TypeScript
compilation, which uses a given file-system.
All tests that interact with the file-system should be tested against each
of the mock file-systems. A series of helpers have been provided to support
such tests:
* `runInEachFileSystem()` - wrap your tests in this helper to run all the
wrapped tests in each of the mock file-systems.
* `addTestFilesToFileSystem()` - use this to add files and their contents
to the mock file system for testing.
* `loadTestFilesFromDisk()` - use this to load a mirror image of files on
disk into the in-memory mock file-system.
* `loadFakeCore()` - use this to load a fake version of `@angular/core`
into the mock file-system.
All ngcc and ngtsc source and tests now use this virtual file-system setup.
PR Close#30921
Add an IndexingContext class to store indexing information and a
transformer module to generate indexing analysis. Integrate the indexing
module with the rest of NgtscProgram and add integration tests.
Closes#30959
PR Close#31151
Optimizations to skip compiling source files that had not changed
did not account for the case where only a resource file changes,
such as an external template or style file.
Now we track such dependencies and trigger a recompilation
if any of the previously tracked resources have changed.
This will require a change on the CLI side to provide the list of
resource files that changed to trigger the current compilation by
implementing `CompilerHost.getModifiedResourceFiles()`.
Closes#30947
PR Close#30954
Template type-checking is enabled by default in the View Engine compiler.
The feature in Ivy is not quite ready for this yet, so this flag will
temporarily control whether templates are type-checked in ngtsc.
The goal is to remove this flag after rolling out template type-checking in
google3 in Ivy mode, and making sure the feature is as compatible with the
View Engine implementation as possible.
Initially, the default value of the flag will leave checking disabled.
PR Close#29698
This commit adds support for compiling the same program repeatedly in a way
that's similar to how incremental builds work in a tool such as the CLI.
* support is added to the compiler entrypoint for reuse of the Program
object between compilations. This is the basis of the compiler's
incremental compilation model.
* support is added to wrap the CompilerHost the compiler creates and cache
ts.SourceFiles in between compilations.
* support is added to track when files are emitted, for assertion purposes.
* an 'exclude' section is added to the base tsconfig to prevent .d.ts
outputs from the first compilation from becoming inputs to any subsequent
compilations.
PR Close#29380
Prior to this change, TypeScript stripped out some imports in case we reference a type that can be represented as a value (for ex. classes). This fix ensures that we use correct symbol identifier, which makes TypeScript retain the necessary import statements.
PR Close#28941
In certain configurations (such as the g3 repository) which have lots of
small compilation units as well as strict dependency checking on generated
code, ngtsc's default strategy of directly importing directives/pipes into
components will not work. To handle these cases, an additional mode is
introduced, and is enabled when using the FileToModuleHost provided by such
compilation environments.
In this mode, when ngtsc encounters an NgModule which re-exports another
from a different file, it will re-export all the directives it contains at
the ES2015 level. The exports will have a predictable name based on the
FileToModuleHost. For example, if the host says that a directive Foo is
from the 'root/external/foo' module, ngtsc will add:
```
export {Foo as ɵng$root$external$foo$$Foo} from 'root/external/foo';
```
Consumers of the re-exported directive will then import it via this path
instead of directly from root/external/foo, preserving strict dependency
semantics.
PR Close#28852
Currently setting `enableIvy` to true runs a hybrid mode of `ngc` and `ngtsc`. This is counterintuitive given the name of the flag itself.
This PR makes the `true` value equivalent to the previous `ngtsc`, and `ngtsc` becomes an alias for `true`. Effectively this removes the hybrid mode as well since there's no other way to enable it.
PR Close#28616
Currently the "ngtsc` testing helpers resolve the `fake_core` NPM
package using the `TEST_SRCDIR` variable. This is problematic on Windows
where Bazel runfiles are not symlinked into the runfiles directory.
In order to properly resolve the NPM Bazel tree artifact, we use the
`resolveTreeNpmArtifact` runfile helper that properly resolves the artifact
properly on all platforms.
PR Close#28352
Since we recently removed the `test.sh` script, and now run
all tests with Bazel, we can remove the unused logic that makes
compiler-cli tests pass in non-Bazel.
This cleans up the tests, and also makes it easier to write tests
without worrying about two ways of the Angular package output
(Bazel `ng_package` rules vs. old `build.sh` logic of building)
PR Close#28352
This commit introduces a new mode for the NgtscTestEnvironment which
builds the NgtscProgram and then asks for the list of lazy routes,
instead of running the TS emit phase.
PR Close#27697
The method `ts.CompilerHost.directoryExists` is optional, and was not
previously handled by our ts.CompilerHost wrapper for factory and
summary shims (GeneratedShimsHostWrapper).
TypeScript checks for the existence of this method and silently ignores
things like typeRoots if it's not found. This commit adds proper handling
of directoryExists() to the shim.
A test is also added which verifies typeRoots behavior works when shims
are enabled.
PR Close#27470
Previously ngtsc assumed resource files (templateUrl, styleUrls) would be
physically present in the file system relative to the .ts file which
referenced them. However, ngc previously resolved such references in the
context of ts.CompilerOptions.rootDirs. Material depends on this
functionality in its build.
This commit introduces resolution of resources by leveraging the TypeScript
module resolver, ts.resolveModuleName(). This resolver is used in a way
which will never succeed, but on failure will return a list of locations
checked. This list is then filtered to obtain the correct potential
locations of the resource.
PR Close#27357
This commit gets ready for the introduction of ngtsc template
type-checking tests by refactoring test environment setup into a
custom helper. This helper will simplify the authoring of future
ngtsc tests.
Ngtsc tests previously returned a numeric error code (a la ngtsc's CLI
interface) if any TypeScript errors occurred. The helper has the
ability to run ngtsc and return the actual array of ts.Diagnostics, which
greatly increases the ability to write clean tests.
PR Close#26203