Angular is a comprehensive framework designed to help developers build dynamic and scalable web applications. At its core, Angular uses a component-based architecture. This means that the user interface is divided into independent, reusable pieces called components. Each component manages its logic and template, making the application modular and easier to maintain.
The structure of an Angular application is organized through modules, which group components and services logically. This modular architecture allows developers to build complex applications by combining smaller, well-defined building blocks. Understanding how components and modules work together is essential to grasping Angular fundamentals.
Angular follows the Model-View-Controller (MVC) design pattern conceptually, though it uses its variation where components act as controllers, templates serve as views, and services manage data and business logic. This separation of concerns helps keep the application organized and scalable.
Observables in Angular
Observables are a powerful concept used in Angular for handling asynchronous data streams and events. They provide a way for different parts of an application to communicate by publishing and subscribing to messages. An observable can emit multiple values over time, which subscribers can listen to and react accordingly.
In Angular applications, observables are used extensively for managing data flows, especially when dealing with user interactions, server responses, or real-time updates. For example, when a user inputs data or clicks a button, observables can be used to capture and respond to those events asynchronously.
Creating observables involves defining a publisher that emits values and one or more subscribers that listen to those emissions. This pattern simplifies managing complex asynchronous tasks by decoupling the production of data from its consumption. Observables also integrate seamlessly with Angular’s HttpClient and other reactive programming libraries, making data handling efficient and clean.
HttpClient in Angular
HttpClient is an essential service provided by Angular for communicating with backend servers through HTTP requests. It simplifies the process of sending requests and handling responses, allowing developers to easily retrieve or send data to APIs.
Angular 6 introduced an updated version of HttpClient, which is more robust and fully integrated with observables. This integration allows developers to handle asynchronous HTTP calls effectively by subscribing to the responses, enabling smooth error handling and response transformations.
HttpClient supports various HTTP methods such as GET, POST, PUT, DELETE, and others. It also handles common tasks like setting headers, handling JSON data, and managing request parameters. This makes it a vital tool for building applications that depend on external data or services.
The previous version of HttpClient still exists in older Angular packages but has been deprecated to encourage migration to the newer, more efficient API. Developers are advised to adopt the updated HttpClient to benefit from better performance and maintainability.
Routing and Navigation
Routing is a core feature of Angular that allows navigation between different views or components within a single-page application (SPA). Unlike traditional web pages, SPAs load a single HTML page and dynamically update the content as users interact with the application.
The Angular Router facilitates this by mapping URL paths to components. When a user clicks a link or performs an action that changes the route, the router displays the appropriate component without reloading the entire page. This creates a seamless and fast user experience.
Routes can also include parameters that allow dynamic content to be loaded based on the URL. For example, a product detail page can display information based on a product ID passed in the route. The router also maintains navigation history, enabling the browser’s back and forward buttons to work naturally within the application.
This feature is essential for building complex applications where users move between different sections or perform actions that require context-sensitive views.
Animations in Angular
Animations enhance user interfaces by providing visual cues and smooth transitions between states. Although animations are not mandatory for functional applications, they play a crucial role in improving the user experience.
Angular includes built-in support for defining animations in a declarative manner. Developers can specify how elements should transition in response to events, such as entering or leaving the DOM, or changing visibility.
Animations help make interfaces more intuitive and engaging by guiding user attention and making interactions feel more natural. Without animations, page transitions can appear abrupt or jarring, potentially confusing users.
By leveraging Angular’s animation system, developers can create polished applications that feel responsive and modern without needing external libraries or complex code.
Upgrading from AngularJS to Angular
The transition from AngularJS (version 1.x) to modern Angular (version 2 and beyond) represents a major shift in framework design and application architecture. AngularJS used a different model based on scopes and controllers, while Angular uses a component-based architecture with improved performance and tooling.
Upgrading an application from AngularJS to Angular can be challenging because the two frameworks are fundamentally different. However, Google and the Angular team have provided tools and resources to ease this migration.
The ngMigration Assistant is one such tool that analyzes existing AngularJS codebases and suggests the best migration paths based on complexity and project size. It helps identify components that need rewriting and estimates the effort required.
Additionally, the ngMigration Forum serves as a community platform where developers can share experiences, ask questions, and find guidance on upgrading projects. This support network helps smooth the transition and addresses common concerns about when and how to upgrade.
While AngularJS applications continue to work and receive support, upgrading to the latest Angular versions is recommended to benefit from improved performance, security, and new features.
In summary, Angular’s fundamental building blocks include components, modules, observables, HttpClient, routing, and animations. Together, these elements form a powerful framework that supports the creation of modern, scalable web applications.
Observables provide a clean way to handle asynchronous data and events, making the app responsive and interactive. HttpClient enables efficient communication with backend services. Routing ensures smooth navigation between different parts of the application without full page reloads, enhancing user experience. Animations add polish and engagement to the interface.
Finally, the journey from AngularJS to Angular involves adopting new architectural patterns and leveraging tools designed to make migration as painless as possible. Mastering these fundamentals equips developers to build and maintain robust Angular applications that meet today’s demanding web standards.
Introduction to Angular 6 Features
Angular 6 introduced a number of significant updates and features aimed at improving the developer experience and enhancing application performance. While the core fundamentals of Angular remained the same, these new features helped streamline development workflows and provided better tooling support. Understanding these features is important for developers who want to leverage the full potential of Angular 6 and build modern web applications efficiently.
This section explores the key features introduced in Angular 6, explaining their purpose and how they benefit the development process.
Angular Elements
One of the most exciting additions in Angular 6 was Angular Elements. This feature allows Angular components to be packaged as custom elements or web components. Essentially, Angular Elements makes it possible to embed Angular components inside non-Angular environments such as React, Vue, or even plain HTML pages.
Web components are a set of web platform APIs that enable the creation of reusable custom elements, which work natively in any modern browser. Angular Elements wraps Angular components with these APIs, so the component can be used as a standalone widget outside the Angular ecosystem.
This provides great flexibility, especially for projects where Angular components need to coexist with other frameworks or legacy applications. Developers can create rich, self-contained UI components that are framework-agnostic, improving code reuse and integration possibilities.
Angular Elements supports all Angular features within the component, including data binding, dependency injection, and lifecycle hooks, making it a powerful tool for hybrid application development.
Service Worker Support and Progressive Web Apps
Service workers are scripts that run in the background of a web application to enable features such as offline support, background sync, and push notifications. Angular 6 enhanced its support for service workers by allowing better configuration and improved handling of navigation URLs.
With Angular’s service worker integration, developers can easily create Progressive Web Apps (PWAs) — web applications that behave like native apps, offering offline functionality and improved performance. Angular 6 introduced the ability to configure navigation URLs so that the service worker redirects navigation requests that do not match any asset or data group to a specified index file.
This ensures that client-side routing works seamlessly with service workers, preventing issues where certain URLs might be improperly cached or fail to load offline.
Additionally, Angular 6 introduced a safety-worker.js file that helps deactivate existing service workers more gracefully, addressing a common pain point when updating or removing service workers from deployed applications.
The improvements in service worker support made Angular 6 a strong candidate for building reliable PWAs, combining the power of Angular with modern web capabilities.
Bye-bye Template Element: ng-template
Angular 6 replaced the older <template> element with <ng-template>. This change was part of a broader effort to clarify and improve template handling in Angular applications.
In earlier versions, the <template> tag was used to define template fragments that Angular could instantiate dynamically, but it was often confused because the HTML <template> element has different behavior in browsers.
The introduction of <ng-template> in Angular 6 provides a clear and consistent way to define template blocks that are not rendered directly but can be used with structural directives like *ngIf or *ngFor.
This change improves code readability and avoids conflicts with native HTML elements, making templates easier to understand and manage.
Angular Ivy: The New Rendering Engine
Angular Ivy was introduced as an experimental rendering and view engine in Angular 6. Although not the default at that time, Ivy represented a major shift in how Angular compiles and renders components.
The primary goal of Angular Ivy is to make the compilation process faster and the generated code smaller and more efficient. Ivy compiles components and their templates directly into optimized JavaScript and HTML, reducing bundle sizes and improving runtime performance.
Ivy introduced two important concepts: locality and tree shaking.
Locality means that Angular compiles each file independently, without needing to analyze the entire application. This allows faster recompilation during development because changes in one component don’t trigger recompilation of the whole app.
Tree shaking is an optimization technique that removes unused code from the final bundle, resulting in smaller files and faster load times. Ivy enables better tree shaking by producing code that is easier for build tools to analyze and prune.
Though still in experimental stages in Angular 6, Ivy laid the foundation for future Angular versions, where it became the default rendering engine due to its benefits in performance and developer productivity.
Removing Whitespace in Templates
Angular 6 introduced a new compiler setting called preserveWhitespaces that controls whether whitespaces in component templates should be preserved during compilation.
By default, Angular 6 preserves whitespaces, which can be useful for certain designs where spacing is critical. However, this can lead to larger bundle sizes and unnecessary DOM nodes if not needed.
Developers can disable this setting in the configuration file to remove extra whitespaces, which reduces the size of the compiled templates and results in more efficient rendering.
Controlling whitespace preservation gives developers flexibility to optimize the application for performance or design requirements.
New Angular CLI Commands: ng add and ng update.
Angular CLI is a command-line interface tool that greatly simplifies development by automating common tasks. Angular 6 introduced two important new commands that improve the workflow:
The ng add command allows developers to add new libraries or features to an existing Angular project quickly. Instead of manually installing packages and configuring the project, ng add installs the required dependencies and applies necessary configuration changes automatically.
This command streamlines the integration of popular tools like Angular Material, PWA support, or other third-party libraries.
The ng update command helps in upgrading the Angular project dependencies to newer versions. It analyzes the project’s package configuration and updates Angular core packages and related dependencies, applying any needed code migrations.
This command reduces the manual effort involved in upgrading Angular applications and helps keep projects up to date with the latest improvements and fixes.
Together, these commands improve developer productivity and simplify managing Angular project dependencies.
Enhanced Service Worker Capabilities
Angular 6 made service worker management more flexible and safer. Previously, removing a service worker from a project was complex, often requiring manual steps to unregister it in browsers.
With the introduction of a safety-worker.js script, Angular 6 provides a way to deactivate existing service workers more reliably during deployment updates or project changes.
Furthermore, navigation requests can now be redirected intelligently through the service worker, improving support for client-side routing and ensuring smoother offline experiences.
These enhancements make service workers easier to implement, manage, and update, encouraging developers to adopt progressive web app technologies.
Improvements in Angular Animations
Animations in Angular 6 saw improvements that simplified their implementation and reduced dependency size.
One major update was the removal of the need for the web-animations-js polyfill in many cases. This polyfill was previously required to support animation features in browsers that lacked native support for the Web Animations API.
By updating the animation implementation, Angular 6 reduced the bundle size and simplified setup, making it easier to include animations without extra dependencies.
This change helps create smoother and more appealing user interfaces while minimizing the impact on application size.
URL Serialization Bug Fix
Angular 6 fixed an important bug related to URL serialization in route parameters. Previously, some characters, such as parentheses and semicolons, were not properly encoded when passed in route parameters, leading to issues in navigation and URL handling.
This bug fix improved the robustness of Angular’s router, ensuring that special characters in URLs are encoded and decoded correctly.
This enhancement makes routing more reliable, especially for applications that use complex parameters or need to handle user-generated input in URLs.
RxJS 6 Update
RxJS, or Reactive Extensions for JavaScript, is a core library for reactive programming in Angular. Angular 6 was upgraded to RxJS version 6, which brought several improvements and changes.
RxJS 6 introduced a more consistent and modular approach to operators, encouraging the use of pipeable operators that improve tree shaking and reduce bundle sizes.
This version also deprecated older APIs and provided migration paths to simplify the upgrade process for existing applications.
Upgrading to RxJS 6 aligns Angular projects with the latest reactive programming standards and improves performance by enabling better optimization during builds.
Bazel Compiler Integration
Bazel is a build tool developed by Google that focuses on fast, incremental builds by only rebuilding changed parts of the application.
Angular 6 integrated Bazel as an optional compiler, enabling faster builds and improved development workflows, especially for large projects.
By using Bazel, Angular developers benefit from reduced build times and more efficient resource usage, which is critical for continuous integration and delivery pipelines.
Bazel integration also opens the door for more advanced build optimizations in future Angular versions.
Internationalization (i18n) Enhancements
Internationalization, or i18n, refers to designing applications to support multiple languages and regional settings.
Angular 6 improved its i18n capabilities by updating the Angular CLI to support easier localization workflows.
Developers can now build applications that dynamically switch languages and formats, making Angular 6 suitable for global applications requiring multilingual support.
These enhancements reduce the complexity of managing translations and localized content, helping teams deliver accessible software to diverse user bases.
Angular 6 brought a range of new features and improvements aimed at enhancing performance, developer productivity, and application scalability. From Angular Elements enabling reusable components in non-Angular apps, to the experimental Ivy renderer promising faster compilation, each feature contributed to a stronger, more versatile framework.
The new CLI commands simplified adding libraries and upgrading projects, while service worker enhancements made Progressive Web Apps more accessible. Updates in animations, URL handling, RxJS, Bazel integration, and internationalization further refined the development experience.
Understanding these features allows developers to build faster, smaller, and more maintainable Angular applications that meet modern web standards and user expectations.
Angular 6 Deprecations and Removals
Angular 6 also marked the beginning of the framework’s effort to clean up deprecated APIs and remove legacy features. This is part of Angular’s commitment to keeping the framework modern and maintainable while encouraging developers to adopt newer, better approaches.
Deprecated APIs
Several APIs and lifecycle hooks were deprecated in Angular 6 to pave the way for better alternatives:
- Renderer: The older Renderer API was deprecated in favor of the more powerful and consistent Renderer2. Developers were encouraged to migrate their code to use Renderer2, which provides better support for different rendering environments.
- reflect-metadata: Angular 6 started moving away from relying on the reflect-metadata polyfill, which was often used for decorators in TypeScript. This was part of the larger effort to reduce polyfill dependencies and improve performance.
Removal of Legacy Features
Angular 6 removed some outdated features that were no longer relevant or replaced by improved mechanisms:
- @angular/http Module: The deprecated HTTP module @angular/http was fully removed, and developers were urged to switch to the more robust @angular/common/http package. This new HTTP client module offers a simplified API, better typed responses, and improved support for interceptors.
By addressing these deprecations and removals, Angular 6 helped ensure that projects remain compatible with future versions and that developers use modern best practices.
Angular Material and CDK Updates
Angular Material is the official UI component library for Angular, providing ready-to-use and accessible UI components following Material Design guidelines. The Component Dev Kit (CDK) offers foundational utilities for building custom components.
In Angular 6, Angular Material and CDK received significant updates:
- Tree component: A new mat-tree component was introduced, enabling hierarchical data display in tree format with support for expandable nodes and flexible data sources.
- Virtual scrolling: CDK’s virtual scrolling module was improved for performance, allowing efficient rendering of large lists by only displaying items visible in the viewport.
- Drag and drop: The CDK drag-and-drop feature was refined with better API and event handling, simplifying the implementation of interactive drag-and-drop interfaces.
- Theming: Angular Material introduced improved theming capabilities, allowing easier customization of component colors and styles through Sass mixins and variables.
These updates made Angular Material a more powerful and versatile toolkit for building modern user interfaces with Angular 6.
Differential Loading for Modern Browsers
Angular 6 pioneered the support for differential loading — a technique where the build process produces two separate bundles: one targeting modern browsers with support for ES2015+ (ES6), and another targeting older browsers with ES5 syntax.
This approach delivers smaller, more efficient bundles to modern browsers, improving load times and performance without sacrificing compatibility with older environments.
Angular CLI automatically detects the target environment based on the browser’s capabilities and loads the appropriate bundle.
Differential loading helps optimize Angular applications for a wide range of browsers with minimal developer effort.
Lazy Loading Improvements
Lazy loading is a key technique for optimizing application startup time by loading feature modules only when they are needed.
Angular 6 improved lazy loading by simplifying the syntax and making it easier to implement:
- The new syntax uses dynamic imports with import() instead of string-based module paths, which enables better type checking and tooling support.
Example:
typescript
CopyEdit
{
path: ‘feature’,
loadChildren: () => import(‘./feature/feature.module’).then(m => m.FeatureModule)
}
This modern syntax allows IDEs to provide better autocompletion and error detection and enables Webpack to perform more efficient bundling.
Angular 6 Performance Enhancements
Several under-the-hood performance improvements were introduced in Angular 6, making applications faster and more efficient:
- Improved build speeds: Angular CLI leveraged better caching and incremental builds, reducing compile times during development.
- Smaller bundles: The combination of Ivy’s experimental optimizations, RxJS 6 tree shaking, and improved Angular CLI build tools led to reduced final bundle sizes.
- Optimized change detection: Angular 6 enhanced the change detection mechanism by minimizing unnecessary checks and updates, improving runtime performance in complex applications.
These improvements collectively contributed to smoother user experiences and faster development workflows.
Angular 6 Testing Enhancements
Testing is a crucial part of Angular development, and Angular 6 introduced several enhancements to the testing infrastructure:
- Updated TestBed APIs: Angular 6 improved the TestBed setup and teardown processes, reducing memory leaks and improving test isolation.
- Better support for asynchronous tests: The framework provided more robust tools for handling async operations in tests, including improved zone management and error reporting.
- CLI Test Improvements: Angular CLI test commands were enhanced with better defaults, faster test runs, and compatibility with popular test runners like Karma and Jasmine.
These testing improvements helped developers write more reliable, maintainable tests and maintain higher code quality.
Updated Angular Package Format (APF)
The Angular Package Format defines how Angular libraries should be packaged for distribution. Angular 6 updated the APF to improve compatibility with modern build tools and optimize packaging.
Key changes included:
- ES2015 module support: Libraries could now provide ES2015 module bundles alongside older formats, enabling better tree shaking and smaller application bundles.
- Improved typings and metadata: Enhanced metadata files allowed better IDE support and static analysis.
- Flat module entry points: The Improved flat module design made it easier to import modules and reduced bundle complexity.
These changes helped Angular libraries integrate more smoothly into applications and build processes.
Angular 6 was an important milestone that set the stage for future improvements by introducing:
- Framework modernization through Ivy and RxJS 6
- Improved developer experience with CLI commands like ng add and ng update.
- Enhanced support for Progressive Web Apps and service workers
- Performance and build optimizations, including differential loading and Bazel integration
- A cleaner API surface with deprecations and removals of legacy features
By adopting Angular 6, developers gained access to cutting-edge tools and features that simplified complex workflows, improved app quality, and prepared applications for the evolving web landscape.
Angular 6 and Progressive Web App (PWA) Support
One of the significant focuses in Angular 6 was enhanced support for building Progressive Web Apps (PWAs). PWAs are web applications that provide native app-like experiences, including offline access, push notifications, and fast load times.
Service Worker Integration
Angular 6 improved the way service workers are integrated into Angular applications. Service workers act as proxies between the web app, the browser, and the network. They enable features like offline support, caching, and background sync.
The Angular CLI introduced better configuration options for service workers, allowing developers to specify navigation URLs and cache strategies in a more flexible way. This included the ability to define fallback URLs, so that navigation requests without a matching asset or data file could still be handled gracefully.
Safety Worker
A common challenge with service workers in previous Angular versions was the difficulty of disabling or removing them once enabled. Angular 6 introduced a safety-worker script that makes it easier to deactivate existing service workers if necessary, providing more control during app updates or rollbacks.
Advantages of Angular’s PWA Support
Offline support ensures users can still interact with the app without an internet connection. Faster loading speeds are achieved thanks to intelligent caching. Push notifications enable re-engagement with users. These improvements lead to a better user experience and increased engagement through app-like behavior. These features empower Angular developers to build high-quality PWAs using built-in tools and best practices.
Internationalization (i18n) Improvements
Angular 6 brought better support for internationalization, making it easier to create applications that support multiple languages and regional settings.
Angular CLI Integration
The Angular CLI incorporates enhanced commands and workflows to streamline the localization process. This included tools to extract translatable strings from the code, easier management of translation files, and building separate application versions for different locales.
Benefits of i18n
With internationalization built into the framework and CLI, developers can reach a broader audience by localizing content, date and time formats, currency, and other culturally specific data. Supporting multiple languages improves accessibility and user satisfaction, especially for global applications.
Angular CLI Enhancements
Angular CLI is an essential tool for Angular developers, simplifying project creation, building, testing, and deployment.
New Commands: ng add and ng update
Angular 6 introduced two powerful commands to improve dependency management. The ng add command allows developers to quickly add new libraries or tools to an Angular project. It automatically installs the package and configures it within the project, reducing manual setup steps. The ng update command helps update Angular dependencies and other packages while applying necessary code migrations. It makes upgrading projects smoother and reduces compatibility issues.
Other CLI Improvements
Build performance was improved with caching and incremental compilation. Better default configurations were introduced for production builds. The CLI also provided more flexible project scaffolding options. These enhancements reduce developer effort, encourage best practices, and maintain project health through simplified upgrades.
Bazel Integration
Bazel is a powerful build tool developed by Google, designed to handle large codebases with fast and incremental builds.
Benefits of Bazel in Angular 6
Incremental builds allow Bazel to rebuild only the changed parts of the application instead of recompiling everything, which greatly speeds up build times. Bazel is highly scalable and supports large projects with multiple modules and dependencies efficiently. It also caches build outputs, allowing reuse across builds and machines. Angular 6 started experimenting with Bazel integration, aiming to provide developers with more efficient build processes, especially for large-scale applications.
Angular Elements
Angular 6 introduced Angular Elements, a new feature that enables Angular components to be packaged as custom elements or web components.
What Are Angular Elements?
Angular Elements allow developers to wrap Angular components and expose them as reusable web components that can be used outside Angular applications. This means Angular components can be embedded in projects built with other frameworks or even plain HTML pages.
Use Cases
They can be used to embed Angular components in React, Vue, or other frameworks. Developers can create reusable UI widgets that can be shared across projects. Angular Elements also enable incrementally adopting Angular in legacy applications. They bridge the gap between Angular and non-Angular environments, promoting greater flexibility and code reuse.
Animations in Angular 6
Animations play a vital role in enhancing user experience by making interactions feel smooth and responsive.
Animation Improvements
Angular 6 improved the animation system by removing the dependency on the web-animations-js polyfill, which reduced bundle size and improved performance. The animation APIs themselves remained consistent, allowing developers to create complex animation sequences using Angular’s animation DSL.
Benefits of Animations
Animations improve user engagement by providing visual feedback, guiding user attention, and making transitions less abrupt. Angular’s robust animation support ensures these effects are both powerful and easy to implement.
Final Thoughts
Angular 6 was a pivotal release that refined the framework’s foundation and enhanced the developer experience with practical new features and improvements.
Key takeaways include a greater emphasis on performance optimization with tools like Bazel and differential loading. There was enhanced support for PWAs and offline capabilities. Developer tools were improved through new Angular CLI commands. Flexibility increased with Angular Elements, enabling interoperability. Angular 6 also continued modernization with Ivy and RxJS updates, laying the groundwork for future Angular versions.
Adopting Angular 6 helps developers build faster, more maintainable, and versatile web applications while preparing for evolving web standards and user expectations.