Currently fallback content for `ng-content` gets declared and rendered out in one go. This breaks down if multiple instances of the same component are used where one doesn't render the fallback content while the other one does, because the `TNode` for the content has to be created during the first creation pass.
These changes resolve the issue by always _declaring_ the template, but only rendering it if the slot is empty.
Fixes#55466.
PR Close#55478
Rework the i18n cleanup behavior to more closely match that of containers. Specifically, we assume that nodes are going to be claimed unless they are part of a branching ICU block.
During hydration, we then track which ICU case was active at serialization time, and which was active during hydration. Any remaining cases that weren't used during hydration are then cleaned up.
PR Close#54823
Add support for hydrating i18n blocks. This is accomplished by serializing information about selected ICU cases for a block during server-side rendering.
During hydration, this data is read and is used to traverse both an AST of the translated message and the DOM, in parallel, to map each LView with an RNode.
Finally, this mapping is used while nodes are being created (either via i18n or their respective instructions) to locate existing nodes.
PR Close#54823
Adds the ability to specify content that Angular should fall back to if nothing is projected into an `ng-content` slot. For example, if we have the following setup
```
@Component({
selector: 'my-comp',
template: `
<ng-content select="header">Default header</ng-content>
<ng-content select="footer">Default footer</ng-content>
`
})
class MyComp {}
@Component({
template: `
<my-comp>
<footer>New footer</footer>
</my-comp>
`
})
class MyApp {}
```
The instance of `my-comp` in the app will have the default header and the new footer.
**Note:** Angular's content projection happens during creation time. This means that dynamically changing the contents of the slot will not cause the default content to show up, e.g. if a `if` block goes from `true` to `false`.
Fixes#12530.
PR Close#54854
In some cases the hydration mismatch is nested within a component.
As the devTool only reports issues on the component level, we need to mark the component node rather than the actual mismatched node.
PR Close#54671
Add an internal API to enable and use i18n hydration for testing and development. This helps ensure that we don't accidentally break the current behavior until we are completely ready to roll out i18n support.
PR Close#54784
This commit adds hydration informations to the devtools.
* List of hydrated/hydrated components
* Shows hydration overlays
* Shows hydration errors for NG0500, 501 & 502
PR Close#53910
In certain cases Angular hydration logic can not rely on the order in which elements are present in a template (for example, in content-projection use-cases) and there is a need to serialize a path from one node to another, so that hydration can locate an element on a page. The logic attempts to use an immediate parent element as an anchor and compute the path from it. If it fails - the path is computed starting from the <body> (this is a fallback).
This commit updates the logic to walk up the parents tree if an immediate parent (from a template) is disconnected from the DOM. This helps to shorten the lookup path and make it more stable.
PR Close#53317
This commit fixes an issue where swapping hydrated views was not possible in the new control flow repeater. The problem was caused by the fact that an internal representation of a view had no indication that hydration is completed and further detaching/attaching should work in a regular (non-hydration) mode. This commit adds a logic that resets a pointer to a dehydrated content and we use this as an indication that the view is swtiched to a regular mode.
Resolves#53163.
PR Close#53274
This commit fixes an issue with hydration, which happens when a content is projected in a certain way, leaving host elements non-projected, but the child content projected.
The fix is to detect such situations and add extra annotations to help runtime logic locate those elements at the right locations.
Resolves#53276.
PR Close#53304
This commit updates the logic to handle hydration of multiple nodes projected in a single slot. Currently, in case component nodes are content-projected and their order is changed during the projection, hydration can not find the correct element. With this fix, extra annotation info would be included for such nodes and hydration logic at runtime will use it to locate the right element.
Resolves#53246.
PR Close#53270
This commit drops the `ɵ` symbol from hydration annotation key: `__ɵnghData__` -> `__nghData__`. This helps ensure that there are no UTF8 symbols that might be damaged in case a web server is misconfigured.
Noticed while working on https://github.com/angular/angular/pull/52206.
PR Close#52207
This commit removes the `withNoDomReuse` function to minimize public API. The `withNoDomReuse` function used to disable DOM reuse, which is the main feature of the `provideClientHydration()`.
The `withNoDomReuse()` function was in the "developer preview" mode, so the removal happens without prior deprecation.
BREAKING CHANGE:
The `withNoDomReuse()` function was removed from the public API. If you need to disable hydration, you can exclude the `provideClientHydration()` call from provider list in your application (which would disable hydration features for the entire application) or use `ngSkipHydration` attribute to disable hydration for particular components. See this guide for additional information: https://angular.io/guide/hydration#how-to-skip-hydration-for-particular-components.
PR Close#52057
Enables the new `@` block syntax by default by removing the `enabledBlockTypes` flags. There are still some internal flags that allow special use cases to opt out of the block syntax, like during XML parsing and when compiling older libraries (see #51979).
PR Close#51994
This commit adds hydration support for repeaters (for loops) and empty blocks. The logic looks up a dehydrated view and use this information for hydration. Otherwise, DOM elements for a view are created from scratch.
PR Close#51920
Prior to this change `this.isStable.pipe(first((isStable) => isStable)).toPromise()` had to be done in multiple places across the framework and the Angular CLI see https://github.com/angular/angular-cli/pull/25856#discussion_r1328158846. In the majority of cases an Observable based `isStable` API is not needed. This also removes the need for RXJS operator imports.
PR Close#51807
This commit updates the `if` and `switch` logic to support hydration. The logic attempts to find dehydrated views in containers while processing `if` and `switch` instructions. If a dehydrated is found, its used to further match elements. Otherwise, DOM elements for a view are created from scratch.
PR Close#51915
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
This commit updates the runtime implementation of defer blocks to avoid their triggering on the server. This behavior was described in the RFC (https://github.com/angular/angular/discussions/50716, see "Server Side Rendering Behavior" section): only a placeholder is rendered on the server at this moment. This commit also updates the logic to make sure that the placeholder content is hydrated after SSR.
PR Close#51530
This commit fixes an issue where serialization of a view container fails in case it uses a component host as an anchor. This fix is similar to the fix from #51247, but for cases when we insert a component (that acts as a host for a view container) deeper in a hierarchy.
Resolves#51318.
PR Close#51456
For cases when a root component also acts as an anchor node for a ViewContainerRef (for example, when ViewContainerRef is injected in a root component), there is a need to serialize information about the component itself, as well as an LContainer that represents this ViewContainerRef. Effectively, we need to serialize 2 pieces of info: (1) hydration info for the root component itself and (2) hydration info for the ViewContainerRef instance (an LContainer). Each piece of information is included into the hydration data (in the TransferState object) separately, thus we end up with 2 ids. Since we only have 1 root element, we encode both bits of info into a single string: ids are separated by the `|` char (e.g. `10|25`, where `10` is the ngh for a component view and 25 is the `ngh` for a root view which holds LContainer).
Previously, we were only including component-related information, thus all the views in the view container remained dehydrated and duplicated (client-rendered from scratch) on the client.
Resolves#51157.
PR Close#51247
non-destructive hydration expects the DOM tree to have the same structure in both places.
With this commit, the app will throw an error if comments are stripped out by the http server (eg by some CDNs).
fixes#51160
PR Close#51170
This commit updates an internal hydration logic to make sure that the content of components with i18n blocks is cleaned up before we start rendering it.
Resolves#50627.
PR Close#50644
Prior to this change in some cases errors tht happen during routing were not being surfaced. This is due to the fact that the router has floating promises, and the platform was being destroyed prior to these being settled.
PR Close#50587
This commit updates the `ApplicationRef.isStable` API to account for
pending rendering task. This is needed as once a pending rendering task
is done, new macrotask and microtask could be created which previously caused these not
to be intercepted and thus ignored when doing SSR.
PR Close#50425
This commit removes unnecessary transfer state escaping and updates this process to be done by the means of a `replacer` and `reviver` method as this removes the need to export the escaping and unescaping methods.
The only thing that we need to escape is `<script` and `</script` which are done by the browsers, but not Node.js.
PR Close#50201
This commit updates hydration logic to support a scenario where a view container that was hydrated and later on projected to a component that skips hydration. Currently, such projected content is extracted from the DOM (since a component that skips hydration needs to be re-created), but never added back, since the current logic treats such content as "already inserted".
Closes#50175.
PR Close#50199
This commit fixes an issue where a root component with an injected ViewContainerRef (for ex. `inject(ViewContainerRef)`) was triggering a certain code path during hydration which didn't handle this case correctly.
Resolves#50133.
PR Close#50136
This adds context to the error message in the case that a DOM node is not found during the hydration process. It outputs the expected DOM structure based on the lView and tNode rather than an unhelpful text message.
PR Close#49977
Hydration relies on a signal from ZoneJS when it becomes stable inside an application, so that Angular can start serialization process on the server or post-hydration cleanup on the client (to remove DOM nodes that remained unclaimed).
Providing a custom or a "noop" ZoneJS implementation may lead to a different timing of the "stable" event, thus triggering the serialization or the cleanup too early or too late. This is not yet a fully supported configuration.
This commit adds a warning (non-blocking) for those cases.
PR Close#49944
This commit updates hydration logic to hanlde a case when the same component is used multiple times in a template and in some of those cases, component is opted-out of hydration, for example:
```
<cmp ngSkipHydration />
<cmp />
```
Previously, the first occurrence of the `<cmp>` would result in storing the `ssrId` on a TView as `null` (since hydration is disabled for the component) and the second component instance reused the `null` as a value, thus also skipping hydration.
With the changes from this commit, the `ssrId` would be set when we come across a hydratable instance. We also make sure that the `ssrId` value never changes after we first set it to a non-`null` value.
PR Close#49943
This commit updates hydration logic to handle cases when there are projection slots present in a template inside of an `<ng-container>` and when there are regular elements follow an <ng-content> slot (see tests for additional information). With this combination, the logic that annotates regular element locations should fallback to calculating a path from a reference node to that node. In case of an <ng-container>, the comment node is located *after* the node that needs an annotation. An existing logic was mistakenly returning an empty path, which was represented as a pointer to teh reference node. This commit fixes that and triggers a fallback to using a component host node as a reference in this case.
Resolves#49918.
PR Close#49920
Empty text nodes are not present in the server-rendered HTML output, thus we inject a special marker
at a text node location to later restore an empty text node at the client. Currently, we treat text nodes with spaces as "empty" as well, however those spaces are present in the HTML and text nodes are created in a browser. Adding extra annotation in this case results in extra text nodes created on the client and may trigger hydration issues. This commit updates the code to avoid treating text nodes with spaces as "empty".
PR Close#49877
Currently, the `ViewRef.rootNodes` output is missing anchor (comment) nodes for inner `ViewContainerRef`s,
when an achor node was created for that instance of a `ViewContainerRef` (which happens in all cases except
when an <ng-container> was used as a host for a view container).
This issue affects hydration logic, which relies on the number of root nodes within a view to properly determine
segments in DOM that belong to a particular view.
Resolves#49849.
PR Close#49867
This commit updates the logic to avoid enabling hydration in case server response doesn't contain hydration-related info serialized. It can happen when `provideClientHydration()` call only happens on the client, but not on the server.
PR Close#49750
This commit updates the logic to detect a situation when hydration support was enabled only on the client. If that happens, Angular produces a warning in a console with a link to the error guide.
PR Close#49743
The Domino DOM emulation library doesn't support shadow DOM. For such components we can not guarantee that client and server representations would match perfectly. To avoid hydration mismatch errors, such components are opted out of hydration.
PR Close#49722
Currently, non-destructive hydration for i18n blocks is not supported (but support is coming!).
This commit updates the serialization logic from throwing an error when it comes across an i18n
block to annotating a component with a skip hydration flag.
PR Close#49722
This commit adds support by default for HTTP caching when using `provideClientHydration`. Users can opt-out of this behaviour by using the `withoutHttpTransferCache` feature.
```ts
import {
bootstrapApplication,
provideClientHydration,
withNoHttpTransferCache,
} from '@angular/platform-browser';
// ...
bootstrapApplication(RootCmp, {
providers: [provideClientHydration(withNoHttpTransferCache())]
});
```
PR Close#49699
This commit adds the `provideClientHydration` function to the public API. This function can be used to enable the non-destructive Angular hydration.
Important note: the non-destructive hydration feature is in Developer Preview mode, learn more about it at https://angular.io/guide/releases#developer-preview.
Before you can get started with hydration, you must have a server side rendered (SSR) application. Follow the [Angular Universal Guide](https://angular.io/guide/universal) to enable server side rendering first. Once you have SSR working with your application, you can enable hydration by visiting your main app component or module and importing `provideClientHydration` from `@angular/platform-browser`. You'll then add that provider to your app's bootstrapping providers list.
```typescript
import {
bootstrapApplication,
provideClientHydration,
} from '@angular/platform-browser';
// ...
bootstrapApplication(RootCmp, {
providers: [provideClientHydration()]
});
```
Alternatively if you are using NgModules, you would add `provideClientHydration` to your root app module's provider list.
```typescript
import {provideClientHydration} from '@angular/platform-browser';
import {NgModule} from '@angular/core';
@NgModule({
declarations: [RootCmp],
exports: [RootCmp],
bootstrap: [RootCmp],
providers: [provideClientHydration()],
})
export class AppModule {}
```
You can confirm hydration is enabled by opening Developer Tools in your browser and viewing the console. You should see a message that includes hydration-related stats, such as the number of components and nodes hydrated.
Co-authored-by: jessicajaniuk <72768744+jessicajaniuk@users.noreply.github.com>
Co-authored-by: alan-agius4 <17563226+alan-agius4@users.noreply.github.com>
PR Close#49666
This commit updates the logic to handle a case when the `ngSkipHydration` attribute is applied to the root node of an app. In this case, the hydration info should not be serialized and the contents of the app on the client should be cleared up before initial rendering.
PR Close#49675
Kristiyan Kostadinov