Creating a service with CLI in Angular - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to generate a new Angular service using the CLI.

Angular

ng generate [1] my-service

Drag options to blanks, or click blank then click option'

Aservice

Bcomponent

Cmodule

Ddirective

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'component' instead of 'service' will create a component, not a service.

Forgetting to specify the type after 'ng generate'.

The Angular CLI command ng generate service creates a new service.

2fill in blank

medium

Complete the command to create a service with the CLI and skip the test file generation.

Angular

ng generate service my-service [1]

Drag options to blanks, or click blank then click option'

A--noTest

B--skip-tests

C--skipTest

D--no-tests

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect flag names like '--no-tests' which are not recognized.

Omitting the flag and getting test files generated.

The --skip-tests flag tells the CLI not to create the test file.

3fill in blank

hard

Fix the error in the command to generate a service named 'data' inside a folder 'shared'.

Angular

ng generate service [1]/data

Drag options to blanks, or click blank then click option'

Ashared

Bshare

Cshared/

D/shared

Attempts:

3 left

💡 Hint

Common Mistakes

Adding a trailing slash after the folder name.

Adding a leading slash before the folder name.

The correct folder path is 'shared/data'. Do not add trailing slashes or leading slashes in the argument.

4fill in blank

hard

Fill in the blanks to generate a service named 'auth' in the 'core' folder and make it provided in root.

Angular

ng generate service [1]/[2] --[3]

Drag options to blanks, or click blank then click option'

Acore

Bauth

CprovidedIn=root

DprovidedInRoot

Attempts:

3 left

💡 Hint

Common Mistakes

Using kebab-case for the flag instead of camelCase.

Swapping folder and service names.

The service path is 'core/auth'. The flag --providedIn=root makes the service available app-wide.

5fill in blank

hard

Fill all three blanks to generate a service named 'logger' in the 'utils' folder, skip tests, and specify flat structure.

Angular

ng generate service [1]/[2] --[3] --skip-tests

Drag options to blanks, or click blank then click option'

Autils

Blogger

Cflat

Dflat-structure

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'flat-structure' instead of 'flat' for the flag.

Omitting the folder or service name.

The service path is 'utils/logger'. The --flat flag creates the service without a folder. The --skip-tests flag skips test files.

Practice

1. What is the main purpose of creating a service in Angular using the CLI?

easy

A. To generate routing modules

B. To share logic and data across multiple components

C. To style components with CSS

D. To create new components automatically

Solution

1. Step 1: Understand Angular services role

   Services in Angular are used to share logic and data between components, avoiding duplication.

2. Step 2: Recognize CLI service creation purpose

   The CLI command generates a service file with proper structure to be injected and reused.

3. Final Answer:

   To share logic and data across multiple components -> Option B

4. Quick Check:

   Services share logic/data = D [OK]

Hint: Services share data/logic, not create components [OK]

Common Mistakes:

• Confusing services with components
• Thinking services handle styling
• Assuming services generate routing

2. Which Angular CLI command correctly creates a new service named data?

easy

A. ng new service data

B. ng create service data

C. ng generate service data

D. ng make service data

Solution

1. Step 1: Recall Angular CLI syntax for services

   The correct command to generate a service is ng generate service [name].

2. Step 2: Match the command with options

   Only ng generate service data uses the correct ng generate service syntax.

3. Final Answer:

   ng generate service data -> Option C

4. Quick Check:

   Use ng generate service for services [OK]

Hint: Use 'ng generate service' to create services [OK]

Common Mistakes:

• Using 'ng create' instead of 'ng generate'
• Confusing 'ng new' for service creation
• Typing 'ng make' which is invalid

3. Given the command ng generate service user, what files are created by default?

medium

A. user.component.ts and user.component.html

B. user.service.js and user.service.test.js

C. user.module.ts and user-routing.module.ts

D. user.service.ts and user.service.spec.ts

Solution

1. Step 1: Understand CLI output for service generation

   The Angular CLI creates a TypeScript service file and a test spec file by default.

2. Step 2: Identify correct file extensions and names

   Files are named user.service.ts and user.service.spec.ts, matching user.service.ts and user.service.spec.ts.

3. Final Answer:

   user.service.ts and user.service.spec.ts -> Option D

4. Quick Check:

   Service + test files = B [OK]

Hint: Service files end with .service.ts and .service.spec.ts [OK]

Common Mistakes:

• Confusing service files with component files
• Expecting .js or .test.js extensions
• Thinking routing or module files are created

4. You ran ng generate service auth but got an error: Unknown command: 'generatee'. What is the likely cause?

medium

A. Typo in the command: 'generatee' instead of 'generate'

B. Service name 'auth' is invalid

C. Angular CLI is not installed

D. Missing --service flag

Solution

1. Step 1: Analyze the error message

   The error says 'Unknown command: generatee', indicating a typo in the command.

2. Step 2: Check command spelling

   The correct command is 'generate', not 'generatee'. This typo causes the error.

3. Final Answer:

   Typo in the command: 'generatee' instead of 'generate' -> Option A

4. Quick Check:

   Check spelling of CLI commands carefully [OK]

Hint: Check command spelling carefully for typos [OK]

Common Mistakes:

• Typing 'generatee' instead of 'generate'
• Assuming service name causes error
• Thinking CLI is missing when it is installed

5. You want to create a service named logger inside a folder shared/utils using Angular CLI. Which command is correct?

hard

A. ng generate service shared/utils/logger

B. ng generate service logger/shared/utils

C. ng generate service shared-utils-logger

D. ng generate service /shared/utils/logger

Solution

1. Step 1: Understand CLI path syntax for nested folders

   Angular CLI uses slash-separated paths to place files in nested folders.

2. Step 2: Identify correct command format

   ng generate service shared/utils/logger correctly uses shared/utils/logger to create the service in nested folders.

3. Final Answer:

   ng generate service shared/utils/logger -> Option A

4. Quick Check:

   Use slash paths for nested service folders [OK]

Hint: Use folder paths with slashes before service name [OK]

Common Mistakes:

• Reversing folder and service name order
• Using dashes instead of slashes for folders
• Starting path with a slash causing errors