Ivy is a complete rewrite of Renderer2 and significantly changes the way the framework renders our applications. In this high-level overview of the changes, Sumit will introduce you to:

• the new rendering pipeline and underlying Ivy engine
• how we can use it to create higher-order components
• the new component factories and dependency injection
• how to easily debug them

Angular 9 Renderer2

Extend this base class to implement custom rendering. By default, Angular renders a template into DOM. You can use custom rendering to intercept rendering calls, or to render to something other than DOM.

abstract class Renderer2 {
  abstract data: {...}
  destroyNode: ((node: any) => void) | null
  abstract destroy(): void
  abstract createElement(name: string, namespace?: string): any
  abstract createComment(value: string): any
  abstract createText(value: string): any
  abstract appendChild(parent: any, newChild: any): void
  abstract insertBefore(parent: any, newChild: any, refChild: any): void
  abstract removeChild(parent: any, oldChild: any, isHostElement?: boolean): void
  abstract selectRootElement(selectorOrNode: any, preserveContent?: boolean): any
  abstract parentNode(node: any): any
  abstract nextSibling(node: any): any
  abstract setAttribute(el: any, name: string, value: string, namespace?: string): void
  abstract removeAttribute(el: any, name: string, namespace?: string): void
  abstract addClass(el: any, name: string): void
  abstract removeClass(el: any, name: string): void
  abstract setStyle(el: any, style: string, value: any, flags?: RendererStyleFlags2): void
  abstract removeStyle(el: any, style: string, flags?: RendererStyleFlags2): void
  abstract setProperty(el: any, name: string, value: any): void
  abstract setValue(node: any, value: string): void
  abstract listen(target: any, eventName: string, callback: (event: any) => boolean | void): () => void
}

Create your custom renderer using RendererFactory2.

Use a custom renderer to bypass Angular’s templating and make custom UI changes that can’t be expressed declaratively. For example if you need to set a property or an attribute whose name is not statically known, use the setProperty() or setAttribute() method.

#angular #angularjs #angular9