NgRuhLazyComponent

A simple utility to dynamically lazy load components into an angular app without routing dependency.

• Much inspiration drawn from https://netbasal.com/the-need-for-speed-lazy-load-non-routable-modules-in-angular-30c8f1c33093 and https://medium.com/@esanjiv/complete-beginner-guide-to-publish-an-angular-library-to-npm-d42343801660

Demo Screen

Benefits

• Reduce your inital app load time by loading only the essential components first
• Reduce the initial payload size
• Leverage lazy loading features WITHOUT routing dependency (Not all apps are route based )
• Ideal for apps that need to build dynamic UIs defined via JSON configs or based on user driven highly customizable UIs
• Prevents unnessasary memory hogging by loading only what is required

Usage

On app.module file import the module

import { NgRuhLazyComponentModule } from 'ng-ruh-lazy-component'; //<-- Add this line

@NgModule({
  declarations: [
    AppComponent,
  ],
  imports: [
    BrowserModule,
    NgRuhLazyComponentModule  //<-- Add this line
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule { }

• On anywhere in your component templates add the following

<ng-ruh-lazy-component 
    componentPath="src/app/modules/lazy-module-1/lazy-module-1.module#LazyModule1Module#Comp1Component"
    [data] = "dataToPushToLoadedComponent">
    <div error>There was a problem loading the component</div>
    <div loading>Loading Component, Please stand by</div>
</ng-ruh-lazy-component>

• componentPath : should take the format of <Path to .module file>#<Name of the module>#<Component Key>
• data : data To Push To Loaded Component
• error directive (Optional) : Allows you to specify html to show when an error is encountered
• loading directive (Optional) : Allows you to specify html to show when the module is loading

Prerequisites

The smallest unit of Angular code that could be lazy loaded is an Angular Module (NGModule) and NOT a Component, Hence ALWAYS make sure you create a module that encapsulates one or more of the Components you need to reload.

• Create your module, use ng g m modules/lazy-module1
• Create 1 or more components under the module, use ng g c modules/lazy-module1/comp1, ng g c modules/lazy-module1/comp2
• on the modules/lazy-module1/lazy-module1.module

@NgModule({
  declarations: [Comp1Component, Comp2Component],
  entryComponents: [Comp1Component, Comp2Component], // <-- Add this line
  imports: [
    CommonModule
  ]
})
export class LazyModule1Module { 
  static componentMap = {                 // <-- Add static property componentMap 
    "Comp1Component" : Comp1Component,    //    to map the string component key with 
    "Comp2Component" : Comp2Component     //     the actual component ref
    }                                     // you can also add a function named getComponentEntry(compType:string) 
}                                               

• On your angular.json on the project root, add the module path the the lazyModules array in the project.<your-app-name>.architect.build.options.lazyModules

 project:{
     <your-app-name>:{
         architect:{
             build:{
                 options:{
                     lazyModules:[
                         ...
                         '<path to .module file(s)>',
                         'src/app/modules/lazy-module1/lazy-module1.module',
                         ...
                     ]
                 }
             }
         }
     }
 }

• Follow above steps for each module that need to be lazy loaded