Dependency injection

Last reviewed May 28, 2026 Content v20260528

Track mode

client_angular

Means

In-browser Angular TS

Reading

~1 min

Level

intermediate

This lesson

This lesson teaches Dependency injection: the concepts, APIs, and habits you need before advancing in Angular.

provide/inject shares data down the tree without prop drilling—pair with caution and clear keys.

You will apply Dependency injection in contexts like: Shared auth, config, and API services injected across feature teams.

Write TypeScript with decorators, click Run—Angular 19 loads from CDN, use the Ng global and mountApp(Component) with selector app-root; printOutput feeds the terminal.

When you can explain the previous lesson's ideas without copying starter code.

Inject services via constructor or inject()—Angular resolves tokens from injectors.

Important interview questions and answers

Q: Why does this matter?
A: Inject services via constructor or inject()—Angular resolves tokens from injectors.

Self-check

Summarize Dependency injection in one sentence.
What would you try next in the playground?

Challenge