Currently when there's a parser error in interpolated text, the compiler reports an error on the entire text node. This can be really noisy in long strings.
These changes switch to reporting the errors on the specific expressions that caused them.
PR Close#62258
Currently we have a `ParserError` that is used for the expression parser and a `ParseError` that is used everywhere else. These changes consolidate them into the `ParseError` to avoid confusion and make it easier to add more context in the future.
PR Close#62160
Currently our expression parser produces two different expressions for writes: `PropertyWrite` (e.g. `foo.bar = 123`) or `KeyedWrite` (e.g. `foo[0] = 123`). This is inconsistent with other ASTs, like TypeScript's, where writes are represented as binary expressions with a `=` operator and it makes it difficult to implement more write operators like `??=`, because we'd essentially have to duplicate them.
These changes switch the expression parser over to produce binary expressions instead.
PR Close#61682
When the expression parser consumes tokens inside a parenthesized expression, it looks for valid tokens until it hits and invalid one or a closing paren. If it finds an invalid token, it reports and error and tries to recover until it finds a closing paren. The problem is that in such cases, it would produce the `ParenthesizedExpression` and continue parsing **from** from the closing paren which would then produce more errors that add noise to the output and result in an incorrect representation of the user's code. E.g. `foo((event.target as HTMLElement).value)` would be recovered to `foo((event.target)).value` instead of `foo((event.target).value)`.
These changes resolve the issue by skipping over the closing paren at the recovery point.
Fixes#61792.
PR Close#61815
Currently we reuse the same binding parser for all expressions in the template. Under the hood, the parser has a single `errors` array that it passes into all ASTs which means that if there's one binding with an error, those errors will be propagated to all other ASTs in the template.
These changes switch to having a unique `errors` array for each AST so we only report errors once.
Relates to #61792.
PR Close#61793
This commit adds the support for the `in` keyword as a relational operator, with the same precedence as the other relational operators (<,>, <=, >=)
BREAKING CHANGE: 'in' in an expression now refers to the operator
PR Close#58432
Moves the logic for parsing event names out into methods on the `BindingParser` so we don't have to duplicate it. Also updates the types to more accurately represent the runtime value.
PR Close#60561
Now that the expression AST contains parenthesized expressions, this
refactors the template pipeline to strip out the ones we don't need.
PR Close#60169
Following up on #60127 which added the concept of a parenthesized
expression to the output AST, this does the same for the expression AST.
PR Close#60169
Add support for the `void` operator in templates and host bindings.
This is useful when binding a listener that may return `false` and
unintentionally prevent the default event behavior.
Ex:
```
@Directive({
host: { '(mousedown)': 'void handleMousedown()' }
})
```
BREAKING CHANGE: `void` in an expression now refers to the operator
Previously an expression in the template like `{{void}}` referred to a
property on the component class. After this change it now refers to the
`void` operator, which would make the above example invalid. If you have
existing expressions that need to refer to a property named `void`,
change the expression to use `this.void` instead: `{{this.void}}`.
PR Close#59894
Reworks the lexer's scanner to produce more than one token at a time. This can be useful for the cases where one token means the end of another one.
Also cleans up the scanner by making all non-essential methods private and using strict equality everywhere.
PR Close#59230
This serializes the expression AST back into a string. This is useful to normalize whitespace in expressions so i18n messages are not affected by insignificant changes (such as going from `{{ foo }}` to `{{\n foo\n}}`).
PR Close#58176
Whenever we parse object property assignment shorthands in expression
ASTs, the AST will have no information about whether the property read
for the `LiteralMap` is built based on the shorthand or not.
Exposing this information in the AST is useful for migrations as those
might need to decompose the shorthand into its longer form to e.g.
invoke a signal read.
PR Close#56405
The following changes help the language service code build in g3:
* `Omit<T>` produces an index signature, so we must access the resulting properties with square bracket (because `noPropertyAccessFromIndexSignature` is on in g3).
* Explicitly export `absoluteFrom` from `packages/compiler-cli/index.ts`, since the `*` re-export is patched out in g3.
* Remove const from a few const enums, since accessing const enums across modules is not compatible with `isolatedModules` (which is on in g3).
PR Close#54726
Currently the listener side two-way listeners are parsed by appending `=$event` to the raw expression. This is problematic, because:
1. It can interfere with other expressions (see #37809).
2. It can lead to confusing error messages because users will see code that they didn't write.
3. It doesn't allow us to further manipulate the expression.
These changes remove the logic that appends `=$event` to resolve the issue. There's also some new logic that checks the expression after it has been parsed to ensure that the result is an assignable expression.
Subsequent commits will update the code that emits the expression to add back the `$event` assignment where it's needed.
PR Close#54154
Currently all the members of `_ParseAST` are public, even though they're all used only within the class. This change marks them as private so that it's explicit which ones are intended to be used outside the class.
PR Close#54154
During the template parsing stage two-way bindings are split up into a property and event binding. All the downstream code treats these binding the same as their one-way equivalents. For some future work we'll have to distinguish between the two so these changes update the `BoundElementProperty.type` and `ParsedEvent.type` to include a `TwoWay` type. All existing call-sites have been updated to treat `TwoWay` the same as `Property`/`Regular`, but more specialized logic will be added in the future.
PR Close#54065
When blocks were initially implemented, they were represented as containers in the i18n AST. This is problematic, because block affect the structure of the message.
These changes introduce a new `BlockPlaceholder` AST node and integrate it into the i18n pipeline. With the new node blocks are represented with the `START_BLOCK_<name>` and `CLOSE_BLOCK_<name>` placeholders.
PR Close#52958
Refactor `compilation.ts` by introducing two new concepts:
1. A compilation unit, which has create and update ops. Compilations of individual views are compilation units, as are individual host bindings.
2. Aa compilation job, which has several compilation units. For example, a whole component is a compilation job, because it can have many view compilation units. A host binding compilation is a job in addition to a unit, because each host binding unit is always a singleton.
Then, we begin modifying phases to accept general compilation jobs instead of component compilations specifically, which will allow us to run them on host bindings. In particular, we update the following phases: `phaseReify`, and `phaseChaining`.
PR Close#50899
In #39004 some logic was introduced that tries to recover invalid expressions by treating the `=` token as a recovery point. It works by skipping ahead to the next recovery point inside the `skip` method which is called whenever an error is reported. This can lead to an infinite loop inside the `parseChain` method which assumes that reporting an error would've skipped over the token, but that won't happen since the `=` token is a recovery point. These changes resolve the infinite loop by breaking the loop if `error` didn't skip to a different token after the error was reported.
Fixes#47131.
PR Close#47151
When parsing interpolations, the input string is _decoded_ from what was
in the orginal template. This means that we cannot soley rely on the input
string to compute source spans because it does not necessarily reflect
the exact content of the original template. Specifically, when there is
an HTML entity (i.e. ` `), this will show up in its decoded form
when processing the interpolation (' '). We need to compute offsets
using the original _encoded_ string.
Note that this problem only surfaces in the splitting of interpolations.
The spans to this point have already been tracked accurately. For
example, given the template ` <div></div>`, the source span for the
`div` is already correctly determined to be 6. Only when we encounter
interpolations with many parts do we run into situations where we need
to compute new spans for the individual parts of the interpolation.
PR Close#44811
For two-way-bindings that use the banana-in-a-box syntax, the compiler
synthesizes an event assignment expression from the primary expression.
It is valid for the primary expression to be terminated by the non-null
operator, however naive string substitution is used for the synthesized
expression, such that the `!` would immediately precede the `=` token,
resulting in the valid `!=` operator token. The expression would still
parse correctly but it doesn't implement the proper semantics, resulting
in incorrect runtime behavior.
Changing the expression substitution to force a space between the
primary expression and the assignment avoids this mistake, but it
uncovers a new issue. The grammar does not allow for the LHS of an
assignment to be the non-null operator, so the synthesized expression
would fail to parse. To alleviate this, the synthesized expression is
parsed with a special parser flag to allow for this syntax.
Fixes#36551
PR Close#37809
So-called "Quote expressions" were added in b6ec2387b3
to support foreign syntax to be used in Angular templates, requiring a custom
template transform to convert them somehow during compilation. Support for template
transforms was originally implemented in a43ed79ee7 but
has since been dropped. Since the compiler is not public API the quote expressions
should not have any usages anymore. Removing support for them can improve error
reporting for expressions that contain a `:`, e.g. binding to a URL without quotes:
```html
<a [href]="http://google.com">Click me</a>
```
Here, `http` would be parsed as foreign "http" quote expression with `//google.com` as
value, later reporting the error "Quotes are not supported for evaluation!" because
there was no template transform to convert that code.
Closes#40398
PR Close#44915
The previous fix for correcting spans with comments in
59eef29a6c
had the unfortunate side effect of _breaking_ the spans with comments
when there was leading whitespace. This happened because the previous
fix was testing one without a comment, identifying that the offset shouldn't
have anything added to it, and then removing that offset adjustment
(`offsets[i] + (expressionText.length - sourceToLex.length)`).
Upon further investigation, this offset adjustment _was actually
necessary_ for when the input had comments, but this was only because
the `stripComments` function used `trim` to remove whitespace for these
cases. This is the real problem -- not only does it create a ton of confusion
but also it means that the behavior of the lexer and resulting spans is
different between inputs with comments and inputs without comments.
After reviewing how the `inputLength` of `_ParseAST` was used, it
appears that the correct behavior would be to _not_ trim the input. The
`inputLength` is used to advance the current index beyond points which
have been processed. This _should_ include any whitespace. Additionally,
`inputLength` doesn't appear to be needed at all. When there was no
comment in the input, it was always equal to the `input.length` anyways.
When there _is_ a comment, it should include that comment anyways to
advance the index beyond the comment.
PR Close#44785
When parsing a binding with a comment at the end of the expression, the
parser previously had logic to offset the parsed spans by the length of the
comment. This logic seemed not to serve any useful purpose, and instead
resulted in the corruption of the spans. For example, in the expression
`{{foo // comment}}`, the parser would map the parsed `foo` `PropertyRead`
node at the location of the characters 'ent' from the comment suffix.
This commit removes that logic, correcting the parsed spans of such nodes in
the presence of comments. Removing this logic does not seem to have caused
any tests to fail.
PR Close#44678
