Playground workflow

Last reviewed May 28, 2026 Content v20260528

Track mode

client_angular

Means

In-browser Angular TS

Reading

~1 min

Level

beginner

This lesson

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

Without Playground workflow, you will struggle to read or extend Angular codebases and playground exercises.

You will apply Playground workflow in contexts like: Large Angular codebases, line-of-business apps, and teams standardized on TypeScript everywhere.

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.

At the start of the track—complete before JSX-heavy lessons that assume you understand the playground.

Use printOutput for values and mountApp(Component) with selector app-root for live previews.

Recommended workflow

Read the concept before editing code.
Click Run in browser to compile TypeScript in the iframe.
Use printOutput(...) for terminal inspection.
For UI lessons: const { Component, signal } = Ng; then mountApp(AppComponent).

Important interview questions and answers

Q: Why does this matter?
A: Use printOutput for values and mountApp(Component) with selector app-root for live previews.

Self-check

Summarize Playground workflow in one sentence.
What would you try next in the playground?

Challenge

First run

Run default code.
Confirm typeof Ng is object.

Done when: terminal shows Ng is available.

Playground

Runs in your browser in a sandboxed frame. Backend runners appear when this track’s profile allows them.

Discussion

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Starter discussion topics

mountApp vs printOutput?
Ng global namespace?

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