4 Common Bugs in Angular (and How to Fix Them)

Angular developers often encounter bugs in their applications, which make them curse the framework and lament at some cryptic red lines on their consoles.

However, because Angular is versatile, fast, and optimized for various platforms, it should not be frustrating when using it to build dynamic single page applications.

For example, Mdixon, an experienced Angular developer from the U.S. who uses practical projects to teach developers how to avoid mistakes in their code, says that “following the best programming practices is the best way of preventing errors in Angular apps and the headache that comes with it.”

In this article, I’m going to talk about four common causes of Angular bugs and flaws and how to stay away from them (like the plague!).

1. Confusion in Terminology

Angular, which usually refers to Angular v2 and above, should not be confused with its predecessor, AngularJS.

Angular does not just refer to a new version of AngularJS; it is a rewrite of the original framework.

Now, AngularJS refers to version 1 of the framework. And, the later versions, from version 2 on, are called Angular without the “JS.”

The latest version of the framework, Angular v6, was released in May 2018. Version 7 is scheduled to be released before the close of the year.

This confusion in terminology often causes developers to misplace and misinterpret implementation of concepts when building applications using the framework, especially when collaborating in a team.

So, to avoid Angular bugs, you need to know the version you are dealing with.

2. Using Modules Incorrectly

Angular modules, called NgModules, are what allow you to organize your application such that it can realize your goals—from beginning to end.

However, if not used well, these modules can be a source of heartache that can cripple your development efforts.

From the onset, you should create a root module. This module serves the critical role of pulling together the other modules, as your app continues to grow.

If you do not include it, incorporating additional features afterward could be problematic and error-prone.

Furthermore, as your app grows, you should ensure you only import the right and necessary modules.

Importing modules you do not know well will increase the bugs in your application.

For example, if you want to deploy your application on a web browser, you need to import the BrowserModule from @angular/platform-browser, and list it in the @NgModuleimports array.

Here is an example:

/* Correctly importing modules so that AppModule can use them */

import{BrowserModule}from'@angular/platform-browser';
import{NgModule}from'@angular/core';
import{AppComponent}from'./app.component';

@NgModule({
  declarations: [
    AppComponent
  ],
  imports:[/* remember to include modules here to avoid Angular bugs */
    BrowserModule,
  ],
  providers:[],
  bootstrap:[AppComponent]
})

exportclassAppModule{ }

You should only import the modules you need; otherwise, you’ll unnecessarily bloat the size of your app and reduce its performance.

3. Improper Naming

Angular developers who do not adhere to proper naming practices often make error-prone and difficult-to-debug applications.

If you follow the correct naming conventions, you’ll reduce naming conflicts, inconsistent references, and unproductive collaboration.

Here are some things you can do to keep off naming-related bugs in your Angular applications:

• Name folders and files to demonstrate their uses, without a second a guess. For example, app/users/users-list.component.ts may be referring to an app component that manages a list of users.
• Use a consistent naming approach throughout your Angular app. For example, you can employ a technique that first names a component’s feature followed by its type (feature.type.ts)—such as naming a file app.component.ts.
• When naming classes, use the conventional upper camel case. This way, it indicates that the classes can be instantiated and constructed as instances.

/* avoid */
    export class userslist {
       constructor() { }
     }

/* recommended */
        export class UsersList {
       constructor() { }
     }

4. Directly Mutating the DOM

Another common bug that plagues Angular applications is directly mutating the DOM.

Besides being regarded as a bad practice, this mistake can also make your Angular app run dismally in platforms other than the browser.

Here is an example that mutates the DOM directly:

@Component({...})
exportclassBugComponent{
   constructor(private _elementRef:ElementRef){}

   getAngularBugs(){
     $('.bug-in-jquery').click();
     this._elementRef.nativeElement.abc ='bug in native element';
     document.getElementById('bug-in-document');
   }
 }

As you can see from the above code, the getAngularBugs function demonstrates three ways to interact with the DOM directly: using jQuery, ElementRef.nativeElement, and the global document object. However, that approach makes your app susceptible to errors.

To mutate the DOM in Angular and avoid errors, use the Renderer2 service (available in v4 and above).

The Renderer2 comes with various methods to alter an element, just like the JavaScript DOM API. You can learn more about its use on the official Angular documentation.

Here is an example of how to use the service to interact with the DOM:

@Component({...})
exportclassBugComponent{
   constructor(private _renderer2:Renderer2,
               private _elementRef:ElementRef){}

   avoidAngularBugs(){
     this._renderer2.setElementProperty(this._elementRef,'add-property-here',true);
   }
 }

Conclusion

The article demonstrated four of the most common issues Angular developers encounter when creating their applications.

As an Angular developer, you should constantly learn from your programming mistakes and avoid repeating them in future.

Additionally, constantly improving your skills using practical projects is the best way to ensure that bugs do not catch you off-guard, even if you are a seasoned developer.

What other bugs do you usually experience in your Angular projects? Please let me know in the comment section below.

Happy bug-free Angular coding!