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What's New in Angular 9? Angular 9 New Features

Angular 9 is the smaller, faster, and easier to use and it will be making Angular developers life easier. The fully version of Angular 9 will be released in the month of October/November 2019.

 Explore this: Angular 9 vs. Angular 8 vs. Angular 7 vs. Angular 6, 5, 4, 2
Added Angular 9 Features -
1.      Added undecorated classes migration schematic in the core.
2.      The formControlName also accepts a number in the form
3.      Now allow selector-less directives as base classes in View Engine in the compiler.
4.      Added support selector-less directive as base classes in Ivy and also make the Ivy compiler the default for ngc.
5.      Convert all ngtsc diagnostics to ts.Diagnostics
6.      bazel: support ts_library targets as entry-points for ng_package.
7.      core: add dynamic queries schematic.
8.      core: Mark TestBed.get as deprecated.
9.      ivy: expose window.ng.getDebugNode helper and also support ng-add in localize package.
10.  ivy: i18n – add syntax support for $localize metadata block.
11.  ivy: i18n – reorganize entry-points for better reuse.
12.  language-service: enable logging on TypeScriptHost.
13.  language-service: provide diagnostic for invalid templateUrls.
14.  language-service: provide diagnostics for invalid styleUrls.

DEPRECATIONS -

core: TestBed.get function is marked as deprecated, use TestBed.inject instead.

 Performance Improvements :
  1. Binding update benchmark and also convert all node-based benchmark to use a testing harness.
  2. Avoid megamorphic reads during property binding.
  3. Avoid repeated lview reads in pipe instructions.
  4. Avoid repeated LView reads in property instructions.
  5. Avoid unnecessary DOM reads in styling instructions.
  6. Initialise TNode inputs / outputs on the first creation pass for the Ivy.
  7. limit TNode.outputs reads for the ivy.

 8. The language-service, keep analyzedModules cache when source files don't change.

 It looks like -
describe('TypeScriptServiceHost', () => {
  it('should not clear caches when external template changes', () => {
    const tsLSHost = new MockTypescriptHost(['/app/main.ts'], toh);
    const tsLS = ts.createLanguageService(tsLSHost);
    const ngLSHost = new TypeScriptServiceHost(tsLSHost, tsLS);
    const oldModules = ngLSHost.getAnalyzedModules();
    tsLSHost.override('/app/test.ng', '<div></div>');
    const newModules = ngLSHost.getAnalyzedModules();
    expect(newModules).toBe(oldModules);
   });

 });

Angular 9 Breaking Changes -

 1) Ivy applications :- 
Previously, in Ivy applications, Hammer providers were included by default. With this commit, apps that want Hammer support must import HammerModule in their root module i.e.

import {HAMMER_PROVIDERS} from './dom/events/hammer_gestures'

 2) ServiceWorker: 
Remove deprecated option versionedFiles from service worker asset group configuration in ngsw-config.json

 Before

 "assetGroups": [
  {
    "name": "test",
    "resources": {
      "versionedFiles": [
        "/**/*.txt"
      ]
    }
  }
]

 After

 "assetGroups": [
  {
    "name": "test",
    "resources": {
      "files": [
        "/**/*.txt"
      ]
    }
  }
]

 Angular 9 Bug Fixes -

common: update $locationShim to notify onChange listeners before emitting AngularJS events.

compiler: return enableIvy true when using readConfiguration
ivy -
1.      Get name directly from nativeNode
2.      Handle empty bindings in template type checker
3.      In ngcc, handle inline exports in commonjs code
4.      The ngcc should only index .d.ts exports within the package
5.      The ngTemplateOutlet error when switching between null and template value

language-service -
1.      Instantiate MetadataResolver once
2.      Remove 'context' used for module resolution
ngcc -
1.      Handle deep imports that already have an extension

2.      Ignore format properties that exist but are undefined

Reference link - https://github.com/angular/angular/blob/master/CHANGELOG.md


Compatibility note: The primary goal of the backward compatibility promise is to ensure that changes in the core framework and tooling don't break the existing ecosystem of components and applications and don't put undue upgrade/migration burden on Angular application and component authors.

Note: Angular versions ^4.0.0 and ^5.0.0 are no longer under support.

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