After the introduction of the view engine, we can drop a lot of code that is not used any more.
This should reduce the size of the app bundles because a lot of this code was not being properly tree-shaken by today's tools even though it was dead code.
When the `enableLegacyTemplate` is set to `false`, `<template>` tags and the
`template` attribute are no more used to define angular templates but are
treated as regular tag and attribute.
The default value is `true`.
In order to define a template, you have to use the `<ng-template>` tag.
This option applies to your application and all the libraries it uses. That is
you should make sure none of them rely on the legacy way to defined templates
when this option is turned off (`false`).
The rationale of this change is to improve the inter-operability with web
components that might make use of the `<template>` tag.
DEPRECATION
The template tags and template attribute are deprecated:
<template ngFor [ngFor]=items let-item><li>...</li></template>
<li template="ngFor: let item of items">...</li>
should be rewritten as:
<ng-template ngFor [ngFor]=items let-item><li>...</li></ng-template>
Note that they still be supported in 4.x with a deprecartion warning in
development mode.
MIGRATION
- `template` tags (or elements with a `template` attribute) should be rewritten
as a `ng-template` tag,
- `ng-content` selectors should be updated to referto a `ng-template` where they
use to refer to a template: `<ng-content selector="template[attr]">` should be
rewritten as `<ng-content selector="ng-template[attr]">`
- if you consume a component relying on your templates being actual `template`
elements (that is they include a `<ng-content selector="template[attr]">`). You
should still migrate to `ng-template` and make use of `ngProjectAs` to override
the way `ng-content` sees the template:
`<ng-template projectAs="template[attr]">`
- while `template` elements are deprecated in 4.x they continue to work.
Aspects: di, query, content projection
Included refactoring:
- use a number as query id
- use a bloom filter for aggregating matched queries of nested elements
- separate static vs dynamic queries
Part of #14013
Included refactoring:
- make ViewData.parentIndex point to component provider index
- split NodeType.Provider into Provider / Directive / Pipe
- make purePipe take the real pipe as argument to detect changes
- order change detection:
1) directive props
2) renderer props
Part of #14013
PR Close#14412
Subclassing errors is problematic since Error returns a
new instance. All of the patching which we do than prevent
proper application of source maps.
PR Close#14160
Removes `CompileIdentifierMetadata.name` / `.moduleUrl`,
as well as `CompileTypeMetadata.name / moduleUrl` and
`CompileFactoryMetadata.name / moduleUrl`.
Tobias Bosch
Victor Berchet
Dzmitry Shylovich
Miško Hevery
Bowen Ni
Chuck Jazdzewski
Joao Dias
Zaven Muradyan