Currently in some scenarios the compiler generates code like `null as any ? foo : bar` which will be invalid with [an upcoming TypeScript change](https://devblogs.microsoft.com/typescript/announcing-typescript-5-6-beta/#disallowed-nullish-and-truthy-checks). These changes switch to generating `0 as any` which is exempt from the change.
**Note:** I'm not starting the work to fully get us on TS 5.6 until the 18.2 release comes out, but this change is necessary to unblock an internal team.
PR Close#57303
Currently we use some short variable names like `t` and `r` in the generated factory functions. They can conflict with local symbols with the same names, if they're used for DI.
These changes rename the parameters to reduce the change for conflicts.
Fixes#57168.
PR Close#57181
This commit addresses a performance bottleneck in the `interpolatedSignalNotInvoked` extended
diagnostic by querying directive metadata instead of consulting the type-checker to determine if
a property binding corresponds with an input.
Fixes#57287
PR Close#57291
Similar to a previous fix that intended to make the JIT transforms
compatible with pre-transforms like e.g. Tsickle, we need to solve
an additional issue where the class properties are synthetic and result
in an `getSourceFile() => undefined` invocation that breaks the import
insertion, causing errors like:
```
TypeError: Cannot read properties of undefined (reading 'fileName')
```
PR Close#57262
Follow-up to #56961 which doesn't appear to have caught all the cases. This change moves the pre-emit untagging to `NgCompiler.prepareEmit` which seems to cover a bit more comared to `NgtscProgram.emit`.
Fixes#57135.
PR Close#57138
PR Close#57202
Currently we use some short variable names like `t` and `r` in the generated factory functions. They can conflict with local symbols with the same names, if they're used for DI.
These changes add a `ɵ` to the generated variables to reduce the chance of conflicts.
Fixes#57168.
PR Close#57181
Some Angular template instructions that follow each other may be chained
together in a single expressions statement, containing a deeply nested
AST of call expressions. The number of chained instructions wasn't previously
limited, so this could result in very deep ASTs that cause stack overflow
errors during TypeScript emit.
This commit introduces a limit to the number of chained instructions to
avoid these problems.
Closes#57066
PR Close#57069
Adds a new extended diagnostic that will flag `@let` declarations that aren't used within the template. The diagnostic can be turned off through the `extendedDiagnostics` compiler option.
PR Close#57033
In #56358 we removed most of the places that untag the references to typecheck files, because it was causing the compiler to throw error when it produces diagnostics. This appears to have caused a regression in TS 5.4 which now emits the synthetic references.
These changes add tagging right before the program emits.
Fixes#56945.
PR Close#56961
When we process `@if` and `@for` blocks, we create a scope around their expressions in order to encapsulate the aliases to them. The problem is that this doesn't represent the actual structure since the expression is part of the outer scope. This surfaces by not raising the "used before declared" diagnostic for `@let` declarations.
These changes resolve the issue by processing the expression as a part of the parent scope.
Fixes#56842.
PR Close#56843
Currently the logic that maps a name to a variable looks at the variables in their definition order. This means that `@let` declarations from parent views will always come before local ones, because the local ones are declared inline whereas the parent ones are hoisted to the top of the function.
These changes resolve the issue by giving precedence to the local variables.
Fixes#56737.
PR Close#56752
When running the JIT transforms in 1P w/ tsickle, tsickle will
transform source files before our custom transforms can run. This is
also impacting the Ivy transform and hence we use `ts.getOriginalNode`
in various places to inspect the source AST for detecting Angular.
For the JIT transform we need to do a similar change so that the
transform could run in 1P.
PR Close#56520
Enables the new `@let` syntax by default.
`@let` declarations are defined as:
1. The `@let` keyword.
2. Followed by one or more whitespaces.
3. Followed by a valid JavaScript name and zero or more whitespaces.
4. Followed by the `=` symbol and zero or more whitespaces.
5. Followed by an Angular expression which can be multi-line.
6. Terminated by the `;` symbol.
Example usage:
```
@let user = user$ | async;
@let greeting = user ? 'Hello, ' + user.name : 'Loading';
<h1>{{greeting}}</h1>
```
Fixes#15280.
PR Close#56715
These changes integrate let declarations into the template pipeline. This involves a few operations:
* Producing a `declareLet` instruction call at creation time to initialize the declaration.
* Producing a `storeLet` instruction call in the place of the let declaration, including the necessary `advance` calls beforehand.
* For let declarations used within their declaration view, moving the `const` to be placed right after the `storeLet` call to ensure the their value has been computed.
* For let declarations that are _only_ used in their declaration view, removing the `storeLet` call and inlining the expression into the constant statement.
PR Close#56299
The linker inserts the constant statements that are needed to support compiled templates
after the import statements of an ESM file, but it failed to account for import statements
that are not at the top of the file. This is typically seen in FESM files where multiple
individual ESMs have been concatenated into a single ESM file, with imports in various places.
The linker would then find the very last import statement to insert the constant statements
after, but this may result in TDZ errors for component templates that have been emitted
earlier in the file.
This commit updates the Babel linker plugin to insert constant statements after the last
import of the first import group, therefore avoiding the TDZ error.
Fixes#56403
PR Close#56431
The import manager ensures generation of unique identifiers when
inserting imports. This is done by inspecting existing identifiers
within the original source file, while also checking if a similar
identifier was generated at an earlier time. This is correct behavior.
We can improve the detection so that the same identifier can be
generated in different files. This is beneficial for schematic/migration
use-cases where we wouldn't want to generate import aliases in multiple
files just because we generated an import to e.g. `input` previously.
E.g. it's fine to generate
```ts
// a.ts
import {input} from '@angular/core';
// b.ts
import {input} from `@angular/core';
// instead of `input as input_1`.
```
PR Close#56406
This PR allows the language service to suggest imports for all directives returned from the
compiler, and generate the TypeScript module import and the decorator import when the component
is selected by the user.
PR Close#55595
Updates the check that prevent writes to template variables in two-way bindings to account for let declarations.
Also fixes some old tests that weren't properly setting up two-way bindings.
PR Close#56199
Integrates let declarations into the template type checker by producing corresponding constants in the TCB.
This also includes a couple of custom diagnostics to flag usages of let before they're declared and illegal writes to let declarations. We can't rely on TS for these checks, because it includes the variable name in the diagnostic.
PR Close#56199
Currently the template syntax errors are extracted in the template type check phase. But in local compilation mode we skip the type check phase. As a result template syntax errors are not displayed. With this change we show the template syntax diagnostics in local mode.
PR Close#55855
Introduces a new `LetDeclaration` into the Render3 AST, simiarly to the HTML AST, and adds an initial integration into the various visitors.
PR Close#55848
Currently we optimize methods that pass both `$index` and the item into a method. We can take this a step further by also optimizing calls that only pass `$index` into the first parameter.
PR Close#55872
