feat(ssr): enhance support for Universal and SSR with stylesheets

* Add `StyleService` class to manage application and retrieval of styles from elements in a
  platform-agnostic manner
* Add virtual stylesheet to store server styles, which applies default styles when breakpoint
  overrides are not present
* While not in the browser (ssr), intercept all style calls and reroute them to the virtual
  stylesheet.
* For server-side rendering, add a new type of MediaQueryList similar to the MockMediaQueryList
  to support manual activation/deactivation of breakpoints
* Add jasmine testing mode for SSR
* Add FlexLayoutServerModule to invoke SSR styling
* Remove unnecessary Renderer references and replace them with DOM APIs
* Add whitespace debugging mode for server styles

Fixes #373.

> See [Design Doc](https://docs.google.com/document/d/1fg04ihw42dJJHGd6fugdiBe39iJot8aErhiE7CjwfmQ/edit#)

Author: CaerusKaru

.travis.yml

@@ -21,6 +21,7 @@ jobs:
     - env: "MODE=lint"
     - env: "MODE=aot"
     - env: "MODE=prerender"
+    - env: "MODE=ssr"
     # Closure Compiler CI check is temporarily disabled until a new version of
     # the tool is released with https://github.com/google/closure-compiler/pull/2600
     # - env: "MODE=closure-compiler"
@@ -38,6 +39,10 @@ env:
   - BROWSER_PROVIDER_READY_FILE=/tmp/flex-layout-build/readyfile
   - BROWSER_PROVIDER_ERROR_FILE=/tmp/flex-layout-build/errorfile
 
+matrix:
+  allow_failures:
+    - env: "MODE=ssr"
+
 
 before_install:
   - source ./scripts/ci/env.sh

package.json

@@ -17,6 +17,7 @@
     "lib:build:aot": "gulp ci:aot",
     "lib:lint": "gulp lint",
     "lib:test": "gulp test",
+    "lib:test:ssr": "gulp test:ssr",
     "universal:build": "gulp universal:build",
     "universal:ci:prerender": "gulp ci:prerender"
   },

scripts/ci/sources/mode.sh

@@ -28,3 +28,7 @@ is_unit() {
 is_prerender() {
   [[ "$MODE" = prerender ]]
 }
+
+is_ssr() {
+  [[ "$MODE" = ssr ]]
+}

scripts/ci/travis-testing.sh

@@ -41,6 +41,8 @@ elif is_prerender; then
   $(npm bin)/gulp ci:prerender
 elif is_closure_compiler; then
   ./scripts/closure-compiler/build-devapp-bundle.sh
+elif is_ssr; then
+  $(npm bin)/gulp ci:ssr
 fi
 
 teardown_tunnel

src/lib/api/core/base-adapter.spec.ts

@@ -5,23 +5,16 @@
  * Use of this source code is governed by an MIT-style license that can be
  * found in the LICENSE file at https://angular.io/license
  */
-import {ElementRef, Renderer2} from '@angular/core';
+import {ElementRef} from '@angular/core';
 import {BaseFxDirectiveAdapter} from './base-adapter';
 import {expect} from '../../utils/testing/custom-matchers';
-import {MediaMonitor} from '@angular/flex-layout/media-query';
-
-export class MockElementRef extends ElementRef {
-  constructor() {
-    const nEl = document.createElement('DIV');
-    super(nEl);
-    this.nativeElement = nEl;
-  }
-}
+import {MediaMonitor} from '../../media-query/media-monitor';
+import {StyleService} from '../../utils/styling/styler';
 
 describe('BaseFxDirectiveAdapter class', () => {
   let component;
   beforeEach(() => {
-    component = new BaseFxDirectiveAdapter('', {} as MediaMonitor, new MockElementRef(), {} as Renderer2, {}); // tslint:disable-line:max-line-length
+    component = new BaseFxDirectiveAdapter('', {} as MediaMonitor, {} as ElementRef, {} as StyleService); // tslint:disable-line:max-line-length
   });
   describe('cacheInput', () => {
     it('should call _cacheInputArray when source is an array', () => {

src/lib/api/core/base-adapter.ts

@@ -5,12 +5,13 @@
  * Use of this source code is governed by an MIT-style license that can be
  * found in the LICENSE file at https://angular.io/license
  */
-import {ElementRef, Inject, PLATFORM_ID, Renderer2} from '@angular/core';
+import {ElementRef} from '@angular/core';
 
 import {BaseFxDirective} from './base';
 import {ResponsiveActivation} from './responsive-activation';
 import {MediaQuerySubscriber} from '../../media-query/media-change';
 import {MediaMonitor} from '../../media-query/media-monitor';
+import {StyleService} from '../../utils/styling/styler';
 
 
 /**
@@ -48,9 +49,8 @@ export class BaseFxDirectiveAdapter extends BaseFxDirective {
   constructor(protected _baseKey: string,   // non-responsive @Input property name
               protected _mediaMonitor: MediaMonitor,
               protected _elementRef: ElementRef,
-              protected _renderer: Renderer2,
-              @Inject(PLATFORM_ID) protected _platformId: Object) {
-    super(_mediaMonitor, _elementRef, _renderer, _platformId);
+              protected _styler: StyleService) {
+    super(_mediaMonitor, _elementRef, _styler);
   }
 
   /**

src/lib/api/core/base.ts

@@ -11,20 +11,13 @@ import {
   SimpleChanges,
   OnChanges,
   SimpleChange,
-  Renderer2,
-  Inject,
-  PLATFORM_ID,
 } from '@angular/core';
 
 import {buildLayoutCSS} from '../../utils/layout-validator';
 import {
   StyleDefinition,
-  lookupStyle,
-  lookupInlineStyle,
-  applyStyleToElement,
-  applyStyleToElements,
-  lookupAttributeValue,
-} from '../../utils/style-utils';
+  StyleService,
+} from '../../utils/styling/styler';
 
 import {ResponsiveActivation, KeyOptions} from '../core/responsive-activation';
 import {MediaMonitor} from '../../media-query/media-monitor';
@@ -70,8 +63,7 @@ export abstract class BaseFxDirective implements OnDestroy, OnChanges {
    */
   constructor(protected _mediaMonitor: MediaMonitor,
               protected _elementRef: ElementRef,
-              protected _renderer: Renderer2,
-              @Inject(PLATFORM_ID) protected _platformId: Object) {
+              protected _styler: StyleService) {
   }
 
   // *********************************************
@@ -85,7 +77,7 @@ export abstract class BaseFxDirective implements OnDestroy, OnChanges {
     return this._elementRef.nativeElement.parentNode;
   }
 
-  protected get nativeElement(): any {
+  protected get nativeElement(): HTMLElement {
     return this._elementRef.nativeElement;
   }
 
@@ -137,19 +129,20 @@ export abstract class BaseFxDirective implements OnDestroy, OnChanges {
 
   /**
    * Quick accessor to the current HTMLElement's `display` style
-   * Note: this allows use to preserve the original style
+   * Note: this allows us to preserve the original style
    * and optional restore it when the mediaQueries deactivate
    */
   protected _getDisplayStyle(source: HTMLElement = this.nativeElement): string {
-    return lookupStyle(this._platformId, source || this.nativeElement, 'display');
+    const query = 'display';
+    return this._styler.lookupStyle(source, query);
   }
 
   /**
    * Quick accessor to raw attribute value on the target DOM element
    */
   protected _getAttributeValue(attribute: string,
                                source: HTMLElement = this.nativeElement): string {
-    return lookupAttributeValue(source || this.nativeElement, attribute);
+    return this._styler.lookupAttributeValue(source, attribute);
   }
 
   /**
@@ -158,36 +151,37 @@ export abstract class BaseFxDirective implements OnDestroy, OnChanges {
    * Check inline style first then check computed (stylesheet) style.
    * And optionally add the flow value to element's inline style.
    */
-  protected _getFlowDirection(target: any, addIfMissing = false): string {
+  protected _getFlowDirection(target: HTMLElement, addIfMissing = false): string {
     let value = 'row';
+    let hasInlineValue = '';
 
     if (target) {
-      value = lookupStyle(this._platformId, target, 'flex-direction') || 'row';
-      let hasInlineValue = lookupInlineStyle(target, 'flex-direction');
+      [value, hasInlineValue] = this._styler.getFlowDirection(target);
 
       if (!hasInlineValue && addIfMissing) {
-        applyStyleToElements(this._renderer, buildLayoutCSS(value), [target]);
+        const style = buildLayoutCSS(value);
+        const elements = [target];
+        this._styler.applyStyleToElements(style, elements);
       }
     }
 
-    return value.trim();
+    return value.trim() || 'row';
   }
 
   /**
    * Applies styles given via string pair or object map to the directive element.
    */
   protected _applyStyleToElement(style: StyleDefinition,
                                  value?: string | number,
-                                 nativeElement: any = this.nativeElement) {
-    let element = nativeElement || this.nativeElement;
-    applyStyleToElement(this._renderer, element, style, value);
+                                 element: HTMLElement = this.nativeElement) {
+    this._styler.applyStyleToElement(element, style, value);
   }
 
   /**
    * Applies styles given via string pair or object map to the directive's element.
    */
-  protected _applyStyleToElements(style: StyleDefinition, elements: HTMLElement[ ]) {
-    applyStyleToElements(this._renderer, style, elements || []);
+  protected _applyStyleToElements(style: StyleDefinition, elements: HTMLElement[]) {
+    this._styler.applyStyleToElements(style, elements);
   }
 
   /**

src/lib/api/ext/class.spec.ts

@@ -5,8 +5,8 @@
  * Use of this source code is governed by an MIT-style license that can be
  * found in the LICENSE file at https://angular.io/license
  */
-import {Component} from '@angular/core';
-import {CommonModule} from '@angular/common';
+import {Component, PLATFORM_ID} from '@angular/core';
+import {CommonModule, isPlatformServer} from '@angular/common';
 import {ComponentFixture, TestBed, async, inject} from '@angular/core/testing';
 
 import {customMatchers, expect} from '../../utils/testing/custom-matchers';
@@ -21,15 +21,19 @@ import {BreakPointRegistry} from '../../media-query/breakpoints/break-point-regi
 
 import {ClassDirective} from './class';
 import {MediaQueriesModule} from '../../media-query/_module';
+import {ServerStylesheet} from '../../utils/styling/server-stylesheet';
+import {StyleService} from '../../utils/styling/styler';
 
 describe('class directive', () => {
   let fixture: ComponentFixture<any>;
   let matchMedia: MockMatchMedia;
+  let platformId: Object;
   let createTestComponent = (template: string) => {
     fixture = makeCreateTestComponent(() => TestClassComponent)(template);
 
-    inject([MatchMedia], (_matchMedia: MockMatchMedia) => {
+    inject([MatchMedia, PLATFORM_ID], (_matchMedia: MockMatchMedia, _platformId: Object) => {
       matchMedia = _matchMedia;
+      platformId = _platformId;
     })();
   };
 
@@ -46,7 +50,9 @@ describe('class directive', () => {
       declarations: [TestClassComponent, ClassDirective],
       providers: [
         BreakPointRegistry, DEFAULT_BREAKPOINTS_PROVIDER,
-        {provide: MatchMedia, useClass: MockMatchMedia}
+        {provide: MatchMedia, useClass: MockMatchMedia},
+        ServerStylesheet,
+        StyleService,
       ]
     });
   });
@@ -224,15 +230,21 @@ describe('class directive', () => {
     fixture.detectChanges();
     let button = queryFor(fixture, '[mat-raised-button]')[0].nativeElement;
 
-    expect(button).toHaveCssClass('mat-raised-button');
+    // TODO(CaerusKaru): MatButton doesn't apply host attributes on the server
+    if (!isPlatformServer(platformId)) {
+      expect(button).toHaveCssClass('mat-raised-button');
+    }
     expect(button).toHaveCssClass('btn-xs');
     expect(button).toHaveCssClass('mat-primary');
 
     fixture.componentInstance.formButtonXs = false;
     fixture.detectChanges();
     button = queryFor(fixture, '[mat-raised-button]')[0].nativeElement;
 
-    expect(button).toHaveCssClass('mat-raised-button');
+    // TODO(CaerusKaru): MatButton doesn't apply host attributes on the server
+    if (!isPlatformServer(platformId)) {
+      expect(button).toHaveCssClass('mat-raised-button');
+    }
     expect(button).not.toHaveCssClass('btn-xs');
     expect(button).toHaveCssClass('mat-primary');
   });

src/lib/api/ext/class.ts

@@ -19,8 +19,6 @@ import {
   SimpleChanges,
   Self,
   OnInit,
-  Inject,
-  PLATFORM_ID,
 } from '@angular/core';
 import {NgClass} from '@angular/common';
 
@@ -29,14 +27,15 @@ import {BaseFxDirectiveAdapter} from '../core/base-adapter';
 import {MediaChange} from '../../media-query/media-change';
 import {MediaMonitor} from '../../media-query/media-monitor';
 import {RendererAdapter} from '../core/renderer-adapter';
+import {StyleService} from '../../utils/styling/styler';
 
 /** NgClass allowed inputs **/
 export type NgClassType = string | string[] | Set<string> | {[klass: string]: any};
 
 /**
  * Directive to add responsive support for ngClass.
  * This maintains the core functionality of 'ngClass' and adds responsive API
- *
+ * Note: this class is a no-op when rendered on the server
  */
 @Directive({
   selector: `
@@ -95,8 +94,8 @@ export class ClassDirective extends BaseFxDirective
               protected _ngEl: ElementRef,
               protected _renderer: Renderer2,
               @Optional() @Self() private _ngClassInstance: NgClass,
-              @Inject(PLATFORM_ID) protected _platformId: Object) {
-    super(monitor, _ngEl, _renderer, _platformId);
+              protected _styler: StyleService) {
+    super(monitor, _ngEl, _styler);
     this._configureAdapters();
   }
 
@@ -139,7 +138,10 @@ export class ClassDirective extends BaseFxDirective
    */
   protected _configureAdapters() {
     this._base = new BaseFxDirectiveAdapter(
-        'ngClass', this.monitor, this._ngEl, this._renderer, this._platformId
+      'ngClass',
+      this.monitor,
+      this._ngEl,
+      this._styler
     );
     if (!this._ngClassInstance) {
       // Create an instance NgClass Directive instance only if `ngClass=""` has NOT been defined on