These token interfaces will make it easier to reason about tokens in the
parser and in specs.
Previously, it was never clear what items could appear in the `parts`
array of a token given a particular `TokenType`. Now, each token interface
declares a labelled tuple for the parts, which helps to document the token
better.
PR Close#42062
Previously, the way templates were tokenized meant that we lost information
about the location of interpolations if the template contained encoded HTML
entities. This meant that the mapping back to the source interpolated strings
could be offset incorrectly.
Also, the source-span assigned to an i18n message did not include leading
whitespace. This confused the output source-mappings so that the first text
nodes of the message stopped at the first non-whitespace character.
This commit makes use of the previous refactorings, where more fine grain
information was provided in text tokens, to enable the parser to identify
the location of the interpolations in the original source more accurately.
Fixes#41034
PR Close#42062
When it was tokenized, text content is split into parts that can include
interpolations and encoded entities tokens.
To make this information available to downstream processing, this commit
adds these tokens to the `Text` AST nodes, with suitable processing.
PR Close#42062
The lexer now splits encoded entity tokens out from text and attribute value tokens.
Previously encoded entities would be decoded and the decoded value would be
included as part of the text token of the surrounding text. Now the entities
have their own tokens. There are two scenarios: text and attribute values.
Previously the contents of `<div>Hello & goodbye</div>` would be a single
TEXT token. Now it will be three tokens:
```
TEXT: "Hello "
ENCODED_ENTITY: "&", "&"
TEXT: " goodbye"
```
Previously the attribute value in `<div title="Hello & goodbye">` would be
a single text token. Now it will be three tokens:
```
ATTR_VALUE_TEXT: "Hello "
ENCODED_ENTITY: "&", "&"
ATTR_VALUE_TEXT: " goodbye"
```
- ENCODED_ENTITY tokens have two parts: "decoded" and "encoded".
- ENCODED_ENTITY tokens are always preceded and followed by either TEXT tokens
or ATTR_VALUE_TEXT tokens, depending upon the context, even if they represent
an empty string.
The HTML parser has been modified to recombine these tokens to allow this
refactoring to have limited effect in this commit. Further refactorings
to use these new tokens will follow in subsequent commits.
PR Close#42062
The lexer now splits interpolation tokens out from attribute value tokens.
Previously the attribute value of `<div attr="Hello, {{ name}}">` would be a single
token. Now it will be three tokens:
```
ATTR_VALUE_TEXT: "Hello, "
ATTR_VALUE_INTERPOLATION: "{{", " name", "}}"
ATTR_VALUE_TEXT: ""
```
- ATTR_VALUE_INTERPOLATION tokens have three parts, "start marker",
"expression" and "end marker".
- ATTR_VALUE_INTERPOLATION tokens are always preceded and followed
by TEXT tokens, even if they represent an empty string.
The HTML parser has been modified to recombine these tokens to allow this
refactoring to have limited effect in this commit. Further refactorings
to use these new tokens will follow in subsequent commits.
PR Close#42062
The lexer now splits interpolation tokens out from text tokens.
Previously the contents of `<div>Hello, {{ name}}<div>` would be a single
text token. Now it will be three tokens:
```
TEXT: "Hello, "
INTERPOLATION: "{{", " name", "}}"
TEXT: ""
```
- INTERPOLATION tokens have three parts, "start marker", "expression"
and "end marker".
- INTERPOLATION tokens are always preceded and followed by TEXT tokens,
even if they represent an empty string.
The HTML parser has been modified to recombine these tokens to allow this
refactoring to have limited effect in this commit. Further refactorings
to use these new tokens will follow in subsequent commits.
PR Close#42062
Angular inserts text either through text nodes (`document.createTextNode`) or using `textContent`, but the drawback of doing so is that HTML entities won't be decoded. In order to work around it, the compiler has some logic that maps the entities to their unicode representation which can safely be inserted. The problem is that our current mapping is arbitrarily limited which means that some entities will be mapped while others will throw an error, even though they're valid.
These changes expand the list to cover all entities that are supported by the HTML spec.
Fixes#41186.
PR Close#42818
In combination with the TS `noImplicitOverride` compatibility changes,
we also want to follow the best-practice of adding `override` to
members which are implemented as part of abstract classes. This
commit fixes all instances which will be flagged as part of the
custom `no-implicit-override-abstract` TSLint rule.
PR Close#42512
Previously the lexer would break out of consuming a text token if it contains
a `<` character. Then if the next characters did not indicate an HTML syntax
item, such as a tag or comment, then it would start a new text token. These
consecutive text tokens are then merged into each other in a post tokenization
step.
In the commit before this, interpolation no longer leaks across text tokens.
The approach given above to handling `<` characters that appear in text is
no longer adequate. This change ensures that the lexer only breaks out of
a text token if the next characters indicate a valid HTML tag, comment,
CDATA etc.
PR Close#42605
When consuming a text token, the lexer tracks whether it is reading characters
from inside an interpolation so that it can identify invalid ICU expressions.
Inside an interpolation there will be no ICU expression so it is safe to
have unmatched `{` characters, but outside an interpolation this is an error.
Previously, if an interpolation was started, by an opening marker (e.g. `{{`)
in a text token but the text came to an end before the closing marker (e.g. `}}`)
then the lexer was not clearing its internal state that tracked that it was
inside an interpolation. When the next text token was being consumed,
the lexer, incorrectly thought it was already within an interpolation.
This resulted in invalid ICU expression errors not being reported.
For example, in the following snippet, the first text block has a prematurely
ended interpolation, and the second text block contains an invalid `{` character.
```
<div>{{</div>
<div>{</div>
```
Previously, the lexer would not have identified this as an error. Now there
will be an EOF error that looks like:
```
TS-995002: Unexpected character "EOF"
(Do you have an unescaped "{" in your template? Use "{{ '{' }}") to escape it.)
```
PR Close#42605
This commit updates the parser logic to continue to try to match an end
tag to an unclosed open tag on the stack. Previously, it would only
push an error to the list and stop looking at unclosed elements.
For example, the invalid HTML of `<li><div></li>`, has an unclosed
element stack of [`li`, `div`] when it encounters the close `li` tag.
We compare against the previously unclosed tag `div` and see that this is
unexpected. Instead of simply giving up here, we continue to move up the
unclosed tags until we find a match (if there is one).
PR Close#42554
The compiler's parsing code has logic to recover from incomplete open
tags (i.e. `<div`) but the recovery logic does not handle when the
incomplete tag is terminated by an EOF. This commit updates the logic to
allow for the EOF character to be interpreted as the end of the tag open
so that the parser can continue processing. It will then fail to find
the end tag and recover by marking the open tag as incomplete.
Part of https://github.com/angular/vscode-ng-language-service/issues/1140
PR Close#41054
If the template parse option `leadingTriviaChars` is configured to
consider whitespace as trivia, any trailing whitespace of an element
would be considered as leading trivia of the subsequent element, such
that its `start` span would start _after_ the whitespace. This means
that the start span cannot be used to mark the end of the current
element, as its trailing whitespace would then be included in its span.
Instead, the full start of the subsequent element should be used.
To harden the tests that for the Ivy parser, the test utility `parseR3`
has been adjusted to use the same configuration for `leadingTriviaChars`
as would be the case in its production counterpart `parseTemplate`. This
uncovered another bug in offset handling of the interpolation parser,
where the absolute offset was computed from the start source span
(which excludes leading trivia) whereas the interpolation expression
would include the leading trivia. As such, the absolute offset now also
uses the full start span.
Fixes#39148
PR Close#40513
The parser has a list of tag definitions that it uses when parsing the template. Each tag has a
`contentType` which tells the parser what kind of content the tag should contain. The problem is
that the browser has two separate `title` tags (`HTMLTitleElement` and `SVGTitleElement`) and each
of them has to have a different `contentType`, otherwise the parser will throw an error further down
the pipeline.
These changes update the tag definitions so that each tag name can have multiple content types
associated with it and the correct one can be returned based on the element's prefix.
Fixes#31503.
PR Close#40259
Similar to #39609 and #38898, though we currently have the knowledge of where the key for an
attribute appears during parsing, we do not propagate this
information to the output AST. This means that once we produce the
template AST, we have no way of mapping a template position to the key
span alone. The best we can currently do is map back to the
sourceSpan. This presents problems downstream, specifically for the
language service, where we cannot provide correct information about a
position in a template because the AST is not granular enough.
PR Close#39613
This commit ensures that when leading whitespace is skipped by
the tokenizer, the original start location (before skipping) is captured
in the `fullStart` property of the token's source-span.
PR Close#39486
The lexer is able to skip leading trivia in the `start` location of tokens.
This makes the source-span more friendly since things like elements
appear to begin at the start of the opening tag, rather than at the
start of any leading whitespace, which could include newlines.
But some tooling requires the full source-span to be available, such
as when tokenizing a text span into an Angular expression.
This commit simply adds the `fullStart` location to the `ParseSourceSpan`
class, and ensures that places where such spans are cloned, this
property flows through too.
PR Close#39486
Let's say we have a code like
```html
<div<span>123</span>
```
Currently this gets parsed into a tree with the element tag `div<span`.
This has at least two downsides:
- An incorrect diagnostic that `</span>` doesn't close an element is
emitted.
- A consumer of the parse tree using it for editor services is unable to
provide correct completions for the opening `<span>` tag.
This patch attempts to fix both issues by instead parsing the code into
the same tree that would be parsed for `<div></div><span>123</span>`.
In particular, we do this by optimistically scanning an open tag as
usual, but if we do not notice a terminating '>', we mark the tag as
"incomplete". A parser then emits an error for the incomplete tag and
adds a synthetic (recovered) element node to the tree with the
incomplete open tag's name.
What's the downside of this? For one, a breaking change.
<ol>
<li>
The first breaking change is that `<` symbols that are ambiguously text
or opening tags will be parsed as opening tags instead of text in
element bodies. Take the code
```html
<p>a<b</p>
```
Clearly we cannot have the best of both worlds, and this patch chooses
to swap the parsing strategy to support the new feature. Of course, `<`
can still be inserted as text via the `<` entity.
</li>
</ol>
Part of #38596
PR Close#38681
Previously, the `sourceSpan` and `startSourceSpan` were the same
object, which meant that you had the following situation:
```
element = <div>some content</div>
sourceSpan = <div>
startSourceSpan = <div>
endSourceSpan = </div>
```
This made `sourceSpan` redundant and meant that if you
wanted a span for the whole element including its content
and closing tag, it had to be computed.
Now `sourceSpan` is separated from `startSourceSpan`
resulting in:
```
element = <div>some content</div>
sourceSpan = <div>some content</div>
startSourceSpan = <div>
endSourceSpan = </div>
```
PR Close#38581
Previously, the `startSourceSpan` property could be null
but in reality it is always well defined - except for a legacy
case in the old i18n extraction/merging code, where the
typings for source-spans are already being undermined.
Making this property non-null, simplifies code elsewhere
in the project.
PR Close#38581
Previously the lexer was responsible for deciding whether an "inline"
template should also have its line-endings normalized.
Now this decision is made higher up in the call stack to allow more
flexibility in the parser/lexer.
PR Close#38581
The HTML parser gets an element's namespace either from the tag name
(e.g. `<svg:rect>`) or from its parent element `<svg><rect></svg>`) which
breaks down when an element is inside of an SVG `foreignElement`,
because foreign elements allow nodes from a different namespace to be
inserted into an SVG.
These changes add another flag to the tag definitions which tells child
nodes whether to try to inherit their namespaces from their parents.
It also adds a definition for `foreignObject` with the new flag,
allowing elements placed inside it to infer their namespaces instead.
Fixes#37218.
PR Close#38477
Within an angular template, when a character entity is unable to be parsed, previously a generic
unexpected character error was thrown. This does not properly express the issue that was discovered
as the issue is actually caused by the discovered character making the whole of the entity unparsable.
The compiler will now instead inform via the error message what string was attempted to be parsed
and what it was attempted to be parsed as.
Example, for this template:
```
<p>
ģp
</p>
```
Before this change:
`Unexpected character "p"`
After this change:
`Unable to parse entity "ģp" - hexadecimal character reference entities must end with ";"`
Fixes#26067
PR Close#38319
HTML is very lenient when it comes to closing elements, so Angular's parser has
rules that specify which elements are implicitly closed when closing a tag.
The parser keeps track of the nesting of tag names using a stack and parsing
a closing tag will pop as many elements off the stack as possible, provided
that the elements can be implicitly closed.
For example, consider the following templates:
- `<div><br></div>`, the `<br>` is implicitly closed when parsing `</div>`,
because `<br>` is a void element.
- `<div><p></div>`, the `<p>` is implicitly closed when parsing `</div>`,
as `<p>` is allowed to be closed by the closing of its parent element.
- `<ul><li>A <li>B</ul>`, the first `<li>` is implicitly closed when parsing
the second `<li>`, whereas the second `<li>` would be implicitly closed when
parsing the `</ul>`.
In all the cases above the parsed structure would be correct, however the source
span of the closing `</div>` would incorrectly be assigned to the element that
is implicitly closed. The problem was that closing an element would associate
the source span with the element at the top of the stack, however this may not
be the element that is actually being closed if some elements would be
implicitly closed.
This commit fixes the issue by assigning the end source span with the element
on the stack that is actually being closed. Any implicitly closed elements that
are popped off the stack will not be assigned an end source span, as the
implicit closing implies that no ending element is present.
Note that there is a difference between self-closed elements such as `<input/>`
and implicitly closed elements such as `<input>`. The former does have an end
source span (identical to its start source span) whereas the latter does not.
Fixes#36118
Resolves FW-2004
PR Close#38126
The html parser already normalizes line endings (converting `\r\n` to `\n`)
for most text in templates but it was missing the expressions of ICU expansions.
In ViewEngine backticked literal strings, used to define inline templates,
were already normalized by the TypeScript parser.
In Ivy we are parsing the raw text of the source file directly so the line
endings need to be manually normalized.
This change ensures that inline templates have the line endings of ICU
expression normalized correctly, which matches the ViewEngine.
In ViewEngine external templates, defined in HTML files, the behavior was
different, since TypeScript was not normalizing the line endings.
Specifically, ICU expansion "expressions" are not being normalized.
This is a problem because it means that i18n message ids can be different on
different machines that are setup with different line ending handling,
or if the developer moves a template from inline to external or vice versa.
The goal is always to normalize line endings, whether inline or external.
But this would be a breaking change since it would change i18n message ids
that have been previously computed. Therefore this commit aligns the ivy
template parsing to have the same "buggy" behavior for external templates.
There is now a compiler option `i18nNormalizeLineEndingsInICUs`, which
if set to `true` will ensure the correct non-buggy behavior. For the time
being this option defaults to `false` to ensure backward compatibility while
allowing opt-in to the desired behavior. This option's default will be
flipped in a future breaking change release.
Further, when this option is set to `false`, any ICU expression tokens,
which have not been normalized, are added to the `ParseResult` from the
`HtmlParser.parse()` method. In the future, this collection of tokens could
be used to diagnose and encourage developers to migrate their i18n message
ids. See FW-2106.
Closes#36725
PR Close#36741
Move the creation of the results objects into the wrapper functions.
This makes it easier to reason about what the parser and lexer classes
are responsible for - you create a new object for each tokenization or
parsing activity and they hold the state of the activity.
PR Close#36741
Previously, an expansion case could only start with an alpha numeric character.
This commit fixes this by allowing an expansion case to start with any character
except `}`.
The [ICU spec](http://userguide.icu-project.org/formatparse/messages) is pretty vague:
> Use a "select" argument to select sub-messages via a fixed set of keywords.
It does not specify what can be a "keyword" but from looking at the surrounding syntax it
appears that it can indeed be any string that does not contain a `}` character.
Closes#31586
PR Close#36123
On a large compilation unit with big templates, the total time spent in
the `PlainCharacterCursor` constructor was 470ms. This commit applies
two optimizations to reduce this time:
1. Avoid the object spread operator within the constructor, as the
generated `__assign` helper in the emitted UMD bundle (ES5) does not
optimize well compared to a hardcoded object literal. This results in a
significant performance improvement. Because of the straight-forward
object literal, the VM is now much better able to optimize the memory
allocations which makes a significant difference as the
`PlainCharacterCursor` constructor is called in tight loops.
2. Reduce the number of `CharacterCursor` clones. Although cloning
itself is now much faster because of the optimization above, several
clone operations were not necessary.
Combined, these changes reduce the total time spent in the
`PlainCharacterCursor` constructor to just 10ms.
PR Close#34332
This is a potential fix for https://github.com/angular/vscode-ng-language-service/issues/235
suggested by @andrius-pra in
47696136e3.
Currently, CRLF line endings are converted to LFs and this causes the
diagnostics span to be off in templates that use CRLF. The line endings
must be preserved in order to maintain correct span offset. The solution
is to add an option to the Tokenizer to indicate such preservation.
PR Close#33241
Similar to interpolation, we do not want to completely remove whitespace
nodes that are siblings of an expansion.
For example, the following template
```html
<div>
<strong>items left<strong> {count, plural, =1 {item} other {items}}
</div>
```
was being collapsed to
```html
<div><strong>items left<strong>{count, plural, =1 {item} other {items}}</div>
```
which results in the text looking like
```
items left4
```
instead it should be collapsed to
```html
<div><strong>items left<strong> {count, plural, =1 {item} other {items}}</div>
```
which results in the text looking like
```
items left 4
```
---
**Analysis of the code and manual testing has shown that this does not cause
the generated ids to change, so there is no breaking change here.**
PR Close#31962
As part of FW-1265, the `@angular/compiler` package is made compatible
with the TypeScript `--strict` flag. This already unveiled a few bugs,
so the strictness flag seems to help with increasing the overall code health.
Read more about the strict flag [here](https://www.typescriptlang.org/docs/handbook/compiler-options.html)
PR Close#30993
Leading trivia, such as whitespace or comments, is
confusing for developers looking at source-mapped
templates, since they expect the source-map segment
to start after the trivia.
This commit adds skipping trivial characters to the lexer;
and then implements that in the template parser.
PR Close#30095
This PR alligns markup language lexer with the previous behaviour in version 7.x:
https://stackblitz.com/edit/angular-iancj2
While this behaviour is not perfect (we should be giving users an error message
here about invalid HTML instead of assuming text node) this is probably best we
can do without more substential re-write of lexing / parsing infrastructure.
This PR just fixes#29231 and restores VE behaviour - a more elaborate fix will
be done in a separate PR as it requries non-trivial rewrites.
PR Close#29328
This PR alligns markup language lexer with the previous behaviour in version 7.x:
https://stackblitz.com/edit/angular-iancj2
While this behaviour is not perfect (we should be giving users an error message
here about invalid HTML instead of assuming text node) this is probably best we
can do without more substential re-write of lexing / parsing infrastructure.
This PR just fixes#29231 and restores VE behaviour - a more elaborate fix will
be done in a separate PR as it requries non-trivial rewrites.
PR Close#29328
BREAKING CHANGE:
Certain elements (like `<tr>` or `<col>`) require parent elements to be of a certain type by the HTML specification
(ex. <tr> can only be inside <tbody> / <thead>). Before this change Angular template parser was auto-correcting
"invalid" HTML using the following rules:
- `<tr>` would be wrapped in `<tbody>` if not inside `<tbody>`, `<tfoot>` or `<thead>`;
- `<col>` would be wrapped in `<colgroup>` if not inside `<colgroup>`.
This meachanism of automatic wrapping / auto-correcting was problematic for several reasons:
- it is non-obvious and arbitrary (ex. there are more HTML elements that has rules for parent type);
- it is incorrect for cases where `<tr>` / `<col>` are at the root of a component's content, ex.:
```html
<projecting-tr-inside-tbody>
<tr>...</tr>
</projecting-tr-inside-tbody>
```
In the above example the `<projecting-tr-inside-tbody>` component culd be "surprised" to see additional
`<tbody>` elements inserted by Angular HTML parser.
PR Close#29219
Previously the start of a character indicated by an escape sequence
was being incorrectly computed by the lexer, which caused tokens
to include the start of the escaped character sequence in the
preceding token. In particular this affected the name extracted
from opening tags if the name was terminated by an escape sequence.
For example, `<t\n>` would have the name `t\` rather than `t`.
This fix refactors the lexer to use a "cursor" object to iterate over
the characters in the template source. There are two cursor implementations,
one expects a simple string, the other expects a string that contains
JavaScript escape sequences that need to be unescaped.
PR Close#28978
