If an <ng-template> contains a structural directive (for example *ngIf), Ngtsc generates extra template function with 1 template instruction call. When <ng-template> tag also contains i18n attribute on it, we generate i18nStart and i18nEnd instructions around it, which is unnecessary and breaking runtime. This commit adds a logic to make sure we do not generate i18n instructions in case only `template` is present.
PR Close#32623
In ngcc's reflection host for UMD and CommonJS bundles, custom logic is
present to resolve import details of an identifier. However, this custom
logic is unable to resolve an import for an identifier inside of
declaration files, as such files use the regular ESM import syntax.
As a consequence of this limitation, ngtsc is unable to resolve
`ModuleWithProviders` imports that are declared in an external library.
In that situation, ngtsc determines the type of the actual `NgModule`
that is imported, by looking in the library's declaration files for the
generic type argument on `ModuleWithProviders`. In this process, ngtsc
resolves the import for the `ModuleWithProviders` identifier to verify
that it is indeed the `ModuleWithProviders` type from `@angular/core`.
So, when the UMD reflection host was in use this resolution would fail,
therefore no `NgModule` type could be detected.
This commit fixes the bug by using the regular import resolution logic
in addition to the custom resolution logic that is required for UMD
and CommonJS bundles.
Fixes#31791
PR Close#32619
In ESM2015 bundles, a class with decorators may be emitted as follows:
```javascript
var MyClass_1;
let MyClass = MyClass_1 = class MyClass {};
MyClass.decorators = [/* here be decorators */];
```
Such a class has two declarations: the publicly visible `let MyClass`
and the implementation `class MyClass {}` node. In #32539 a refactoring
took place to handle such classes more consistently, however the logic
to find static properties was mistakenly kept identical to its broken
state before the refactor, by looking for static properties on the
implementation symbol (the one for `class MyClass {}`) whereas the
static properties need to be obtained from the symbol corresponding with
the `let MyClass` declaration, as that is where the `decorators`
property is assigned to in the example above.
This commit fixes the behavior by looking for static properties on the
public declaration symbol. This fixes an issue where decorators were not
found for classes that do in fact have decorators, therefore preventing
the classes from being compiled for Ivy.
Fixes#31791
PR Close#32619
In ngcc's reflection hosts for compiled JS bundles, such as ESM2015,
special care needs to be taken for classes as there may be an outer
declaration (referred to as "declaration") and an inner declaration
(referred to as "implementation") for a given class. Therefore, there
will also be two `ts.Symbol`s bound per class, and ngcc needs to switch
between those declarations and symbols depending on where certain
information can be found.
Prior to this commit, the `NgccReflectionHost` interface had methods
`getClassSymbol` and `findClassSymbols` that would return a `ts.Symbol`.
These class symbols would be used to kick off compilation of components
using ngtsc, so it is important for these symbols to correspond with the
publicly visible outer declaration of the class. However, the ESM2015
reflection host used to return the `ts.Symbol` for the inner
declaration, if the class was declared as follows:
```javascript
var MyClass = class MyClass {};
```
For the above code, `Esm2015ReflectionHost.getClassSymbol` would return
the `ts.Symbol` corresponding with the `class MyClass {}` declaration,
whereas it should have corresponded with the `var MyClass` declaration.
As a consequence, no `NgModule` could be resolved for the component, so
no components/directives would be in scope for the component. This
resulted in errors during runtime.
This commit resolves the issue by introducing a `NgccClassSymbol` that
contains references to both the outer and inner `ts.Symbol`, instead of
just a single `ts.Symbol`. This avoids the unclarity of whether a
`ts.Symbol` corresponds with the outer or inner declaration.
More details can be found here: https://hackmd.io/7nkgWOFWQlSRAuIW_8KPPwFixes#32078
Closes FW-1507
PR Close#32539
This patch is a final major refactor in styling Angular.
This PR includes three main fixes:
All temporary state taht is persisted between template style/class application
and style/class application in host bindings is now removed.
Removes the styling() and stylingApply() instructions.
Introduces a "direct apply" mode that is used apply prop-based
style/class in the event that there are no map-based bindings as
well as property collisions.
PR Close#32259
PR Close#32596
This patch is a final major refactor in styling Angular.
This PR includes three main fixes:
All temporary state taht is persisted between template style/class application
and style/class application in host bindings is now removed.
Removes the styling() and stylingApply() instructions.
Introduces a "direct apply" mode that is used apply prop-based
style/class in the event that there are no map-based bindings as
well as property collisions.
PR Close#32259
Replaces the `select` instruction with a new one called `advance`. Instead of the jumping to a specific index, the new instruction goes forward X amount of elements. The advantage of doing this is that it should generate code the compresses better.
PR Close#32516
The `goog.getMsg()` function requires placeholder names to be camelCased.
This is not the case for `$localize`. Here placeholder names need
match what is serialized to translation files.
Specifically such placeholder names keep their casing but have all characters
that are not in `a-z`, `A-Z`, `0-9` and `_` converted to `_`.
PR Close#32509
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
This gives an overview of how much time is spent in each operation/phase
and makes it easy to do rough comparisons of how different
configurations or changes affect performance.
PR Close#32427
`ngcc` supports both synchronous and asynchronous execution. The default
mode when using `ngcc` programmatically (which is how `@angular/cli` is
using it) is synchronous. When running `ngcc` from the command line
(i.e. via the `ivy-ngcc` script), it runs in async mode.
Previously, the work would be executed in the same way in both modes.
This commit improves the performance of `ngcc` in async mode by
processing tasks in parallel on multiple processes. It uses the Node.js
built-in [`cluster` module](https://nodejs.org/api/cluster.html) to
launch a cluster of Node.js processes and take advantage of multi-core
systems.
Preliminary comparisons indicate a 1.8x to 2.6x speed improvement when
processing the angular.io app (apparently depending on the OS, number of
available cores, system load, etc.). Further investigation is needed to
better understand these numbers and identify potential areas of
improvement.
Inspired by/Based on @alxhub's prototype: alxhub/angular@cb631bdb1
Original design doc: https://hackmd.io/uYG9CJrFQZ-6FtKqpnYJAA?view
Jira issue: [FW-1460](https://angular-team.atlassian.net/browse/FW-1460)
PR Close#32427
This commit adds a new `TaskQueue` implementation that supports
executing multiple tasks in parallel (while respecting interdependencies
between them).
This new implementation is currently not used, thus the behavior of
`ngcc` is not affected by this change. The parallel `TaskQueue` will be
used in a subsequent commit that will introduce parallel task execution.
PR Close#32427
This change does not alter the current behavior, but makes it easier to
introduce `TaskQueue`s implementing different task selection algorithms,
for example to support executing multiple tasks in parallel (while
respecting interdependencies between them).
Inspired by/Based on @alxhub's prototype: alxhub/angular@cb631bdb1
PR Close#32427
Previously, `ngcc` needed to store some metadata related to the
processing of each entry-point. This metadata was stored in a `Map`, in
the form of `EntryPointProcessingMetadata` and passed around as needed.
After some recent refactorings, it turns out that this metadata (with
its only remaining property, `hasProcessedTypings`) was no longer used,
because the relevant information was extracted from other sources (such
as the `processDts` property on `Task`s).
This commit cleans up the code by removing the unused code and types.
PR Close#32427
In the past, a task's processability didn't use to be known in advance.
It was possible that a task would be created and added to the queue
during the analysis phase and then later (during the compilation phase)
it would be found out that the task (i.e. the associated format
property) was not processable.
As a result, certain checks had to be delayed, until a task's processing
had started or even until all tasks had been processed. Examples of
checks that had to be delayed are:
- Whether a task can be skipped due to `compileAllFormats: false`.
- Whether there were entry-points for which no format at all was
successfully processed.
It turns out that (as made clear by the refactoring in 9537b2ff8), once
a task starts being processed it is expected to either complete
successfully (with the associated format being processed) or throw an
error (in which case the process will exit). In other words, a task's
processability is known in advance.
This commit takes advantage of this fact by moving certain checks
earlier in the process (e.g. in the analysis phase instead of the
compilation phase), which in turn allows avoiding some unnecessary work.
More specifically:
- When `compileAllFormats` is `false`, tasks are created _only_ for the
first suitable format property for each entry-point, since the rest of
the tasks would have been skipped during the compilation phase anyway.
This has the following advantages:
1. It avoids the slight overhead of generating extraneous tasks and
then starting to process them (before realizing they should be
skipped).
2. In a potential future parallel execution mode, unnecessary tasks
might start being processed at the same time as the first (useful)
task, even if their output would be later discarded, wasting
resources. Alternatively, extra logic would have to be added to
prevent this from happening. The change in this commit avoids these
issues.
- When an entry-point is not processable, an error will be thrown
upfront without having to wait for other tasks to be processed before
failing.
PR Close#32427
Previously, `ngcc`'s programmatic API would run and complete
synchronously. This was necessary for specific usecases (such as how the
`@angular/cli` invokes `ngcc` as part of the TypeScript module
resolution process), but not for others (e.g. running `ivy-ngcc` as a
`postinstall` script).
This commit adds a new option (`async`) that enables turning on
asynchronous execution. I.e. it signals that the caller is OK with the
function call to complete asynchronously, which allows `ngcc` to
potentially run in a more efficient mode.
Currently, there is no difference in the way tasks are executed in sync
vs async mode, but this change sets the ground for adding new execution
options (that require asynchronous operation), such as processing tasks
in parallel on multiple processes.
NOTE:
When using the programmatic API, the default value for `async` is
`false`, thus retaining backwards compatibility.
When running `ngcc` from the command line (i.e. via the `ivy-ngcc`
script), it runs in async mode (to be able to take advantage of future
optimizations), but that is transparent to the caller.
PR Close#32427
This change does not alter the current behavior, but makes it easier to
introduce new types of `Executors` , for example to do the required work
in parallel (on multiple processes).
Inspired by/Based on @alxhub's prototype: alxhub/angular@cb631bdb1
PR Close#32427
To persist some of its state, `ngcc` needs to update `package.json`
files (both in memory and on disk).
This refactoring abstracts these operations behind the
`PackageJsonUpdater` interface, making it easier to orchestrate them
from different contexts (e.g. when running tasks in parallel on multiple
processes).
Inspired by/Based on @alxhub's prototype: alxhub/angular@cb631bdb1
PR Close#32427
In order to prevent `ngcc`'d packages (e.g. libraries) from getting
accidentally published, `ngcc` overwrites the `prepublishOnly` npm
script to log a warning and exit with an error. In case we want to
restore the original script (e.g. "undo" `ngcc` processing), we keep a
backup of the original `prepublishOnly` script.
Previously, running `ngcc` a second time (e.g. for a different format)
would create a backup of the overwritten `prepublishOnly` script (if
there was originally no `prepublishOnly` script). As a result, if we
ever tried to "undo" `ngcc` processing and restore the original
`prepublishOnly` script, the error-throwing script would be restored
instead.
This commit fixes it by ensuring that we only back up a `prepublishOnly`
script, iff it is not the one we created ourselves (i.e. the
error-throwing one).
PR Close#32427
Prior to this commit, complex expressions (that require additional statements to be generated) were handled incorrectly in case they were used in attributes annotated with i18n flags. The problem was caused by the fact that extra statements were not appended to the temporary vars block, so they were missing in generated code. This commit updated the logic to use the `convertPropertyBinding`, which contains the necessary code to append extra statements. The `convertExpressionBinding` function was removed as it duplicates the `convertPropertyBinding` one (for the most part) and is no longer used.
PR Close#32309
Previously the template compiler would generate the same jsdoc comment
block for `$localize` as for `goog.getMsg()`. But it turns out that
the closure compiler will complain if the `@desc` and `@meaning`
tags are used for non-`getMsg()` calls.
For now we do not generate the comments for `$localize` calls. They are
not being used at the moment.
In the future it would be good to be able to extract the descriptions and
meanings from the `$localize` calls rather than relying upon the `getMsg()`
calls, which we do now. So we need to find a workaround for this constraint.
PR Close#32473
This commit changes the Angular compiler (ivy-only) to generate `$localize`
tagged strings for component templates that use `i18n` attributes.
BREAKING CHANGE
Since `$localize` is a global function, it must be included in any applications
that use i18n. This is achieved by importing the `@angular/localize` package
into an appropriate bundle, where it will be executed before the renderer
needs to call `$localize`. For CLI based projects, this is best done in
the `polyfills.ts` file.
```ts
import '@angular/localize';
```
For non-CLI applications this could be added as a script to the index.html
file or another suitable script file.
PR Close#31609
Previously, any diagnostics reported during the compilation of an
entry-point would not be shown to the user, but either be ignored or
cause a hard crash in case of a `FatalDiagnosticError`. This is
unfortunate, as such error instances contain information on which code
was responsible for producing the error, whereas only its error message
would not. Therefore, it was quite hard to determine where the error
originates from.
This commit introduces behavior to deal with error diagnostics in a more
graceful way. Such diagnostics will still cause the compilation to fail,
however the error message now contains formatted diagnostics.
Closes#31977
Resolves FW-1374
PR Close#31996
The Angular compiler has an emulation system for various kinds of
filesystems and runs its testcases for all those filesystems. This
allows to verify that the compiler behaves correctly in all of the
supported platforms, without needing to run the tests on the actual
platforms.
Previously, the emulated Windows mode would normalize rooted paths to
always include a drive letter, whereas the native mode did not perform
this normalization. The consequence of this discrepancy was that running
the tests in native Windows was behaving differently compared to how
emulated Windows mode behaves, potentially resulting in test failures
in native Windows that would succeed for emulated Windows.
This commit adds logic to ensure that paths are normalized equally for
emulated Windows and native Windows mode, therefore resolving the
discrepancy.
PR Close#31996
If a project has nested projects that contain node_modules folders
that get processed by ngcc, it can be confusing when the ngcc
version changes since the error message is very generic:
```
The ngcc compiler has changed since the last ngcc build.
Please completely remove `node_modules` and try again.
```
This commit augments the error message with the path of
the entry-point that failed so that it is more obvious which
node_modules folder to remove.
BREAKING CHANGE:
This commit removes the public export of `hasBeenProcessed()`.
This was exported to be availble to the CLI integration but was never
used. The change to the function signature is a breaking change in itself
so we remove the function altogether to simplify and lower the public
API surface going forward.
PR Close#32396
Reworks the compiler to output the factories for directives, components and pipes under a new static field called `ngFactoryFn`, instead of the usual `factory` property in their respective defs. This should eventually allow us to inject any kind of decorated class (e.g. a pipe).
**Note:** these changes are the first part of the refactor and they don't include injectables. I decided to leave injectables for a follow-up PR, because there's some more cases we need to handle when it comes to their factories. Furthermore, directives, components and pipes make up most of the compiler output tests that need to be refactored and it'll make follow-up PRs easier to review if the tests are cleaned up now.
This is part of the larger refactor for FW-1468.
PR Close#31953
When ngcc is called for a specific entry-point, it has to determine
which dependencies to transitively process. To accomplish this, ngcc
traverses the full import graph of the entry-points it encounters, for
which it uses a dependency host to find all module imports. Since
imports look different in the various bundle formats ngcc supports, a
specific dependency host is used depending on the information provided
in an entry-points `package.json` file. If there's not enough
information in the `package.json` file for ngcc to be able to determine
which dependency host to use, ngcc would fail with an error.
If, however, the entry-point is not compiled by Angular, it is not
necessary to process any of its dependencies. None of them can have
been compiled by Angular so ngcc does not need to know about them.
Therefore, this commit changes the behavior to avoid recursing into
dependencies of entry-points that are not compiled by Angular.
In particular, this fixes an issue for packages that have dependencies
on the `date-fns` package. This package has various secondary
entry-points that have a `package.json` file only containing a `typings`
field, without providing additional fields for ngcc to know which
dependency host to use. By not needing a dependency host at all, the
error is avoided.
Fixes#32302
PR Close#32303
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
Previously, ngtsc attempted to use the .d.ts schema for HTML elements to
check bindings to DOM properties. However, the TypeScript lib.dom.d.ts
schema does not perfectly align with the Angular DomElementSchemaRegistry,
and these inconsistencies would cause issues in apps. There is also the
concern of supporting both CUSTOM_ELEMENTS_SCHEMA and NO_ERRORS_SCHEMA which
would have been very difficult to do in the existing system.
With this commit, the DomElementSchemaRegistry is employed in ngtsc to check
bindings to the DOM. Previous work on producing template diagnostics is used
to support generation of this different kind of error with the same high
quality of error message.
PR Close#32171
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
When a template contains a binding without a value, the template parser
creates an `EmptyExpr` node. This would previously be translated into
an `undefined` value, which would cause a crash downstream as `undefined`
is not included in the allowed type, so it was not handled properly.
This commit prevents the crash by returning an actual expression for empty
bindings.
Fixes#30076Fixes#30929
PR Close#31594
This commit switches the default value of the enableIvy flag to true.
Applications that run ngc will now by default receive an Ivy build!
This does not affect the way Bazel builds in the Angular repo work, since
those are still switched based on the value of the --define=compile flag.
Additionally, projects using @angular/bazel still use View Engine builds
by default.
Since most of the Angular repo tests are still written against View Engine
(particularly because we still publish VE packages to NPM), this switch
also requires lots of `enableIvy: false` flags in tsconfigs throughout the
repo.
Congrats to the team for reaching this milestone!
PR Close#32219
This option makes ngc behave as tsc, and was originally implemented before
ngtsc existed. It was designed so we could build JIT-only versions of
Angular packages to begin testing Ivy early, and is not used at all in our
current setup.
PR Close#32219
Previously, `ngcc` assumed that if a format property was defined in
`package.json` it would point to a valid format-path (i.e. a file that
is an entry-point for a specific format). This is generally the case,
except if a format property is set to a non-string value (such as
`package.json`) - either directly in the `package.json` (which is unusual)
or in ngcc.config.js (which is a valid usecase, when one wants a
format property to be ignored by `ngcc`).
For example, the following config file would cause `ngcc` to throw:
```
module.exports = {
packages: {
'test-package': {
entryPoints: {
'.': {
override: {
fesm2015: undefined,
},
},
},
},
},
};
```
This commit fixes it by ensuring that only format properties whose value
is a string are considered by `ngcc`.
For reference, this regression was introduced in #32052.
Fixes#32188
PR Close#32205
During the dependency analysis phase of ngcc, imports are resolved to
files on disk according to certain module resolution rules. Since module
specifiers are typically missing extensions, or can refer to index.js
barrel files within a directory, the module resolver attempts several
postfixes when searching for a module import on disk. Module specifiers
that already include an extension, however, would fail to be resolved as
ngcc's module resolver failed to check the location on disk without
adding any postfixes.
Closes#32097
PR Close#32181
During the recursive processing of dependencies, ngcc resolves the
requested file to an actual location on disk, by testing various
extensions. For recursive calls however, the path is known to have been
resolved in the module resolver. Therefore, it is safe to move the path
resolution to the initial caller into the recursive process.
Note that this is not expected to improve the performance of ngcc, as
the call to `resolveFileWithPostfixes` is known to succeed immediately,
as the provided path is known to exist without needing to add any
postfixes. Furthermore, the FileSystem caches whether files exist, so
the additional check that we used to do was cheap.
PR Close#32181
ngcc needs to solve a unique problem when compiling typings for an
entrypoint: it must resolve a declaration within a .js file to its
representation in a .d.ts file. Since such .d.ts files can be used in deep
imports without ever being referenced from the "root" .d.ts, it's not enough
to simply match exported types to the root .d.ts. ngcc must build an index
of all .d.ts files.
Previously, this operation had a bug: it scanned all .d.ts files in the
.d.ts program, not only those within the package. Thus, if a class in the
program happened to share a name with a class exported from a dependency's
.d.ts, ngcc might accidentally modify the wrong .d.ts file, causing a
variety of issues downstream.
To fix this issue, ngcc's .d.ts scanner now limits the .d.ts files it
indexes to only those declared in the current package.
PR Close#32129
One of the compiler's tasks is to enumerate the exports of a given ES
module. This can happen for example to resolve `foo.bar` where `foo` is a
namespace import:
```typescript
import * as foo from './foo';
@NgModule({
directives: [foo.DIRECTIVES],
})
```
In this case, the compiler must enumerate the exports of `foo.ts` in order
to evaluate the expression `foo.DIRECTIVES`.
When this operation occurs under ngcc, it must deal with the different
module formats and types of exports that occur. In commonjs code, a problem
arises when certain exports are downleveled.
```typescript
export const DIRECTIVES = [
FooDir,
BarDir,
];
```
can be downleveled to:
```javascript
exports.DIRECTIVES = [
FooDir,
BarDir,
```
Previously, ngtsc and ngcc expected that any export would have an associated
`ts.Declaration` node. `export class`, `export function`, etc. all retain
`ts.Declaration`s even when downleveled. But the `export const` construct
above does not. Therefore, ngcc would not detect `DIRECTIVES` as an export
of `foo.ts`, and the evaluation of `foo.DIRECTIVES` would therefore fail.
To solve this problem, the core concept of an exported `Declaration`
according to the `ReflectionHost` API is split into a `ConcreteDeclaration`
which has a `ts.Declaration`, and an `InlineDeclaration` which instead has
a `ts.Expression`. Differentiating between these allows ngcc to return an
`InlineDeclaration` for `DIRECTIVES` and correctly keep track of this
export.
PR Close#32129
In Angular today, the following pattern works:
```typescript
export class BaseDir {
constructor(@Inject(ViewContainerRef) protected vcr: ViewContainerRef) {}
}
@Directive({
selector: '[child]',
})
export class ChildDir extends BaseDir {
// constructor inherited from BaseDir
}
```
A decorated child class can inherit a constructor from an undecorated base
class, so long as the base class has metadata of its own (for JIT mode).
This pattern works regardless of metadata in AOT.
In Angular Ivy, this pattern does not work: without the @Directive
annotation identifying the base class as a directive, information about its
constructor parameters will not be captured by the Ivy compiler. This is a
result of Ivy's locality principle, which is the basis behind a number of
compilation optimizations.
As a solution, @Directive() without a selector will be interpreted as a
"directive base class" annotation. Such a directive cannot be declared in an
NgModule, but can be inherited from. To implement this, a few changes are
made to the ngc compiler:
* the error for a selector-less directive is now generated when an NgModule
declaring it is processed, not when the directive itself is processed.
* selector-less directives are not tracked along with other directives in
the compiler, preventing other errors (like their absence in an NgModule)
from being generated from them.
PR Close#31379
Andrew Kushnir
JoostK
Matias Niemelä
crisbeto
Pete Bacon Darwin
Carlos Ortiz García
George Kalpakas
Kara Erickson
Paul Gschwendtner
Alex Rickabaugh
Alan
atscott
Elvis Begovic