Allow `@Component.deferredImports` to be an object mapping block names to arrays of dependencies, and support `@defer (name blockName)` syntax to configure block-specific dependency lists in both standard and local compilation modes.
This enables more targeted dependency chunk generation during local compilation instead of over-eagerly loading all deferred imports together.
Finalizes compiler implementation of the new `hydrate` triggers by:
* Reworking the logic that was depending on the `hydrateSpan` to distinguish hydrate triggers from non-hydrate triggers.
* Fixing that the `hydrate when` trigger didn't have a `hydrateSpan`.
* Adding an error if a parameter is passed into a `hydrate` trigger.
* Add an error if other `hydrate` triggers are used with `hydrate never`.
* Replacing the `prefetch` and `hydrate` flags in the template pipeline with a `modifiers` field.
* Fixing an error that was being thrown when reifying `hydrate` triggers in the pipeline.
* Adding quick info support for the `hydrate` keyword in the language service.
* Adding some tests for the new logic.
PR Close#57831
Two key refactors to enable deeper language service support for blocks:
(1) We now generate accurate source spans for the various block types. Additionally, all the top-level source spans for a block are now *inclusive* of all the connected or descending blocks. This helps the language service visit connected blocks.
(2) The language service's template visitor was previously skipping over the AST nodes corresponding to several block types. We are now careful to visit all such nodes.
PR Close#52038
Adds support for defining `viewport`, `interaction` and `hover` triggers with no parameters. If the framework encounters such a case, it resolves the trigger to the root element of the `@placeholder` block. Triggers with no parameters have the following restrictions:
1. They have to be placed on an `@defer` block that has an `@placeholder`.
2. The `@placeholder` can only have one root node.
3. The root placeholder node has to be an element.
PR Close#51922
Switches the syntax for blocks from `{#block}{/block}` to `@block {}` based on the feedback from the community.
Read more about the decision-making process in our blog: https://blog.angular.io/meet-angulars-new-control-flow-a02c6eee7843
The existing block types changed in the following ways:
**Conditional blocks:**
```html
<!-- Before -->
{#if cond}
Main content
{:else if otherCond}
Else if content
{:else}
Else content
{/if}
<!-- After -->
@if (cond) {
Main content
} @else if (otherCond) {
Else if content
} @else {
Else content
}
```
**Deferred blocks**
```html
<!-- Before -->
{#defer when isLoaded}
Main content
{:loading} Loading...
{:placeholder} <icon>pending</icon>
{:error} Failed to load
{/defer}
<!-- After -->
@defer (when isLoaded) {
Main content
} @loading {
Loading...
} @placeholder {
<icon>pending</icon>
} @error {
Failed to load
}
```
**Switch blocks:**
```html
<!-- Before -->
{#switch value}
{:case 1}
One
{:case 2}
Two
{:default}
Default
{/switch}
<!-- After -->
@switch (value) {
@case (1) {
One
}
@case (2) {
Two
}
@default {
Default
}
}
```
**For loops**
```html
<!-- Before -->
{#for item of items; track item}
{{item.name}}
{:empty} No items
{/for}
<!-- After -->
@for (item of items; track item) {
{{item.name}}
} @empty {
No items
}
```
PR Close#51891
Adds validations for the following invalid deferred block structures:
* Duplicated triggers.
* Multiple `minimum` parameters on `placeholder` and `loading` blocks.
* Multiple `after` parameters on `loading` blocks.
PR Close#51262
Stores the `deferred` block triggers as a map instead of an array, because triggers can't be duplicated and because having to search through an array will be inconvenient later on.
I've also added a `DeferredBlock.visitAll` method to deduplicate the logic from the various visitor implementations.
PR Close#51262
Adds the logic to create `defer`-specific AST nodes from the generic HTML `BlockGroup` and `Block`. The logic for parsing the triggers will be in the next commit.
PR Close#51050
Alex Rickabaugh