This is a pre-requisite for #40360. Given the following template which has a listener
that references a variable from a parent template (`name`):
```
<ng-template let-name="name">
<button (click)="hello(name)"></button>
</ng-template>
```
We generate code that looks that looks like. Note how we access `name` through `ctx`:
```js
function template(rf, ctx) {
if (rf & 1) {
const r0 = ɵɵgetCurrentView();
ɵɵelementStart(0, "button", 2);
ɵɵlistener("click", function() {
ɵɵrestoreView(r0);
const name_r0 = ctx.name; // Note the `ctx.name` access here.
const ctx_r1 = ɵɵnextContext();
return ctx_r1.log(name_r0);
});
ɵɵelementEnd();
}
}
```
This works fine at the moment, because the template context object can't be changed after creation.
The changes in #40360 allow for the object to be changed, which means that the `ctx` reference
inside the listener will be out of date, because it was bound during creation mode.
This PR aims to address the issue by accessing the context inside listeners through the saved
view reference. With the new code, the generated code from above will look as follows:
```js
function template(rf, ctx) {
if (rf & 1) {
const r0 = ɵɵgetCurrentView();
ɵɵelementStart(0, "button", 2);
ɵɵlistener("click", function() {
const restoredCtx = ɵɵrestoreView(r0);
const name_r0 = restoredCtx.name;
const ctx_r1 = ɵɵnextContext();
return ctx_r1.log(name_r0);
});
ɵɵelementEnd();
}
}
```
PR Close#40833
Because the query now has `flags` which specify the mode, the static query
instruction can now be remove. It is simply normal query with `static` flag.
PR Close#40091
Previous implementation would fire changes `QueryList.changes.subscribe`
whenever the `QueryList` was recomputed. This resulted in artificially
high number of change notifications, as it is possible that recomputing
`QueryList` results in the same list. When the `QueryList` gets recomputed
is an implementation detail and it should not be the thing which determines
how often change event should fire.
This change introduces a new `emitDistinctChangesOnly` option for
`ContentChildren` and `ViewChildren`.
```
export class QueryCompWithStrictChangeEmitParent {
@ContentChildren('foo', {
// This option will become the default in the future
emitDistinctChangesOnly: true,
})
foos!: QueryList<any>;
}
```
PR Close#40091
This commit changes the `PartialComponentLinker` to use the original source
of an external template when compiling, if available, to ensure that the
source-mapping of the final linked code is accurate.
If the linker is given a file-system and logger, then it will attempt
to compute the original source of external templates so that the final
linked code references the correct template source.
PR Close#40237
The linker is implemented using a Babel transform such that Babel needs
to parse and walk a source file to find the declarations that need to be
compiled. If it can be determined that a source file is known not to
contain any declarations the parsing and walking can be skipped as a
performance improvement. This commit adds an exposed function for tools
that integrate the linker to use to allow short-circuiting of the linker
transform.
PR Close#40137
Refactors the i18n error tests to be unit tests in ngtsc_spec.ts. There
is two reasons for doing this.
First is that the tests in compliace_old expected an expection to be be
thrown but did not fail the test if no exception was thrown. That means
that this test could miss catching a bug. It is also a big hacky to call
compile directly and expect an exception to be thrown for diagnostics.
Also, this can easily be unit tested and an end-to-end test is not
necessary since we are not making use of the goldfiles for these tests.
It is easier to maintain and less hacky to validate that we get helpful
error messages when nesting i18n sections by calling getDiagnostics
directly.
PR Close#40026
Prior to this change, the `setClassMetadata` call would be invoked
inside of an IIFE that was marked as pure. This allows the call to be
tree-shaken away in production builds, as the `setClassMetadata` call
is only present to make the original class metadata available to the
testing infrastructure. The pure marker is problematic, though, as the
`setClassMetadata` call does in fact have the side-effect of assigning
the metadata into class properties. This has worked under the assumption
that only build optimization tools perform tree-shaking, however modern
bundlers are also able to elide calls that have been marked pure so this
assumption does no longer hold. Instead, an `ngDevMode` guard is used
which still allows the call to be elided but only by tooling that is
configured to consider `ngDevMode` as constant `false` value.
PR Close#39987
This commit provides the machinery for the new file-based compliance test
approach for i18n tests, and migrates the i18n tests to this new format.
PR Close#39661
In production mode this flag defaults to `true`, but the compliance
tests override this to `false` unless it is provided. As such, the
linker should also adhere to this default as otherwise the compilation
output would not align with the output of the full tests.
There are still tests that exercise the value of this flag, together
with it being `undefined` to verify the behavior of the actual default
value.
PR Close#39707
The linker does not currently support outputting ES5 syntax, so any
compliance tests that request ES5 output cannot be run in partial
compilation mode. This commit marks these tests as pending.
PR Close#39707
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
This commit renames the original `compliance` test directory to `compliance_old`.
Eventually this directory will be deleted once all the tests have been
migrated to the new test case based compliance tests.
PR Close#39617
Kristiyan Kostadinov
Misko Hevery
Pete Bacon Darwin
JoostK
Zach Arend
Alex Rickabaugh