Is AOT (ahead of time) the default compilation in Angular 7

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Starting with Angular version 9, the default compilation of choice is AOT, This means that whenever you build your Angular application for production with the command ng build --prod, the application will also be compiled as part of the build process

Example_snippet/controller/utility/_compilation.js/ ng build --prod. . .
ng build--prod
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The ahead-of-time (AOT) compiler can catch template errors early and improve performance by compiling at build time,,Learn how to use ahead-of-time compilation

Example_snippet/controller/utility/_compilation.js/ <button (click)="toggleHeading. . .
<button (click)="toggleHeading()">Toggle Heading</button>
<h1 *ngIf="showHeading">Hello Angular</h1>

<h3>List of Heroes</h3>
<div *ngFor="let hero of heroes">{{hero}}</div>
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Just-in-Time (JIT), which compiles your application in the browser at runtime, This was the default until Angular 8

Example_snippet/controller/utility/_compilation.js/ content_copy . . .
  selector: 'app-typical',
  template: '<div>A typical component for {{}}</div>'
export class TypicalComponent {
  @Input() data: TypicalData;
  constructor(private someService: SomeService) { ... }
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Why should you use the Ahead of Time compiler ?,Why and When Should you use Just In Time Compiler ?,What is Ahead of Time (AOT) compiler ?,In simple words, when you serve/build your angular application, the Ahead of Time compiler converts your code during the build time before your browser downloads and runs that code, From Angular 9, by default compiling option is set to true for ahead of time compiler

Example_snippet/controller/utility/_compilation.js/ ng build OR ng serve. . .
ng build OR ng serve
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JIT compilation is the default when you run the ng build (build only) or ng serve (build and serve locally) CLI commands, This is for development

Example_snippet/controller/utility/_compilation.js/ ng build. . .
ng build
Step 2 continued with ng serve. . .
ng serve
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An application can be executed with AoT during development using the following command:,By the end of this Angular AoT tutorial, you will understand:,Though Angular CLI provides all the required setup for development of a matured Angular application, you might want to use your own custom webpack based setup,,AoT can be used to render the application in both development and production modes

Example_snippet/controller/utility/_default.js/ import { Component } from '@an. . .
import { Component } from '@angular/core';

  selector: 'app-root',
  template: `<span>{{title}}</span>
  <br />
  <button (click)="changeTitle()">Click here!</button>`,
  styles: [`
  span {
    font-family: cursive
export class AppComponent {
  title = 'Hello world!';
  private count = 0;

    this.title = `Changed! ${this.count}`;
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Ahead-of-Time (AOT), which compiles your app at build time,,JIT compilation is the default when you run the ng build (build only) or ng serve (build and serve locally) CLI commands:,Just-in-Time (JIT), which compiles your app in the browser at runtime

Example_snippet/controller/utility/_default.js/ ``` ng build ng serve ``` . . .
ng build
ng serve
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it is for production, For development (ng serve) the default is JIT

Example_snippet/controller/utility/_default.js/ options { "aot": true, } . . .
options {
   "aot": true,