feat(checkbox): enable checkbox global configuration

src/app/demo/checkbox-demo/checkbox-demo.module.ts

@@ -4,6 +4,8 @@ import { RouterModule } from '@angular/router';
 import { CheckboxDemoComponent } from './checkbox-demo.component';
 import { UiModule } from '../../ui/ui.module';
 import { FormsModule } from '@angular/forms';
+import { IW_CHECKBOX_CONFIG } from '../../ui/checkbox/checkbox.config';
+import { CheckboxConfig } from '../../ui/checkbox/checkbox-config.interface';
 
 @NgModule({
   imports: [
@@ -15,6 +17,12 @@ import { FormsModule } from '@angular/forms';
     FormsModule
   ],
   declarations: [CheckboxDemoComponent],
-  exports: [RouterModule]
+  exports: [RouterModule],
+  providers: [{
+    provide: IW_CHECKBOX_CONFIG,
+    useValue: <CheckboxConfig> {
+      containerClass: 'demo-checkbox'
+    }
+  }]
 })
 export class CheckboxDemoModule { }

src/app/ui/checkbox/checkbox-config.interface.ts

@@ -0,0 +1,4 @@
+
+export interface CheckboxConfig {
+  containerClass?: string;
+}

src/app/ui/checkbox/checkbox.config.ts

@@ -0,0 +1,4 @@
+import { InjectionToken } from '@angular/core';
+import { CheckboxConfig } from './checkbox-config.interface';
+
+export const IW_CHECKBOX_CONFIG = new InjectionToken<CheckboxConfig>('iw-checkbox.config');

src/app/ui/checkbox/checkbox/checkbox.component.ts

@@ -7,12 +7,18 @@ import {
   HostListener,
   HostBinding,
   Input,
-  ChangeDetectorRef
+  ChangeDetectorRef,
+  Optional,
+  Inject,
+  Renderer,
+  ElementRef
 } from '@angular/core';
 import {
   ControlValueAccessor,
   NG_VALUE_ACCESSOR
 } from '@angular/forms';
+import { CheckboxConfig } from '../checkbox-config.interface';
+import { IW_CHECKBOX_CONFIG } from '../checkbox.config';
 
 @Component({
   selector: 'iw-checkbox',
@@ -36,11 +42,23 @@ export class CheckboxComponent implements OnInit, ControlValueAccessor {
   @HostBinding('class.checkbox--disabled')
   isDisabled: boolean;
 
-  constructor(private changeDetectorRef: ChangeDetectorRef) {
+  constructor(
+    private renderer: Renderer,
+    private elementRef: ElementRef,
+    private changeDetectorRef: ChangeDetectorRef,
+    @Optional() @Inject(IW_CHECKBOX_CONFIG) private checkboxConfig: CheckboxConfig
+  ) {
     this.onChangeCb = this.onTouchedCb = () => {};
   }
 
   ngOnInit() {
+    if (this.checkboxConfig && this.checkboxConfig.containerClass) {
+      this.renderer.setElementClass(
+        this.elementRef.nativeElement,
+        this.checkboxConfig.containerClass,
+        true
+      );
+    }
   }
 
   onKeyup($event: KeyboardEvent) {