Now we are ready to build the final Angular version of the Task Board app.

The goal of this part is not only to show code structure. It is to show how the earlier design decisions become a coherent Angular implementation.

Step 1: Start with a modern Angular shape

For a current Angular application, a good beginner-friendly baseline is:

  • standalone components
  • typed models
  • a feature state service
  • signals for state
  • computed values for derived state
  • reactive forms for editing
  • Angular routing for page boundaries

This setup maps closely to how Angular is presented today.

Step 2: Create the core types first

Before building components, define the data shapes.

export type TaskStatus = 'todo' | 'doing' | 'done';
export type TaskPriority = 'low' | 'medium' | 'high';

export interface Task {
  id: string;
  title: string;
  description: string;
  status: TaskStatus;
  priority: TaskPriority;
  dueDate: string | null;
  createdAt: string;
}

export interface TaskDraft {
  title: string;
  description: string;
  status: TaskStatus;
  priority: TaskPriority;
  dueDate: string | null;
}

export interface TaskFilters {
  search: string;
  status: 'all' | TaskStatus;
}

Doing this early helps every other layer.

Step 3: Build the feature state service around signals

The state service is the heart of the feature.

It can hold writable signals for source state:

  • tasks
  • filters
  • selected task ID
  • whether the form is open
  • current editing task ID

Then it can expose computed state:

  • filtered tasks
  • selected task
  • stats
  • form mode
  • draft for the current editing context

This is one of the best places to teach the difference between source state and derived state.

Why signals fit well here

Signals make dependencies explicit. A computed value such as filteredTasks can depend on tasks and filters. When either changes, Angular knows it should update consumers.

That gives the feature a very clean reactive core without manually wiring update chains.

Step 4: Keep persistence behind a dedicated layer

Even if the app only uses local storage, it is helpful to separate persistence concerns.

That means one layer handles things like:

  • load initial tasks
  • save updated tasks
  • seed sample data if storage is empty

Why bother in a small tutorial?

Because this teaches a habit that scales. If the app later moves from local storage to HTTP APIs, the rest of the feature should not need to know much about that change.

Step 5: Build the page shell

The route-level TaskBoardPageComponent should compose the feature.

It can:

  • inject the state service
  • read the main signals and computed values
  • pass values to child components
  • respond to child outputs by calling state-service methods

This keeps the page responsible for composition, not for every detail.

Step 6: Build the toolbar as a focused communication surface

The toolbar is a great example of disciplined communication.

It should:

  • display the current search text and status filter
  • emit changes or call a clean page-level contract
  • trigger add mode intentionally

What it should not do:

  • manipulate the task list directly
  • compute stats
  • know how persistence works

This makes it a good teaching example for parent-child and feature-state coordination.

Step 7: Build the stats component as a pure read model

The stats component should be as close to dumb and pure as possible.

It receives counts and renders them.

This is useful pedagogically because it shows beginners that not every component needs its own business logic. Some components simply present data.

Step 8: Build the list and list item components carefully

The task list can receive the filtered tasks and selected ID.

The list item component can receive:

  • the task
  • whether it is selected

And emit:

  • selected
  • edit requested
  • delete requested

This is a strong example of explicit contracts. Each component has a small public API.

It also avoids the anti-pattern where list items directly mutate global objects or reach into sibling UI.

Step 9: Build the details component as a state-driven view

The details panel should simply reflect the selected task.

If nothing is selected, it can show an empty state.

This is a perfect example of declarative rendering. There is no need for imperative show/hide code. The template can express:

  • if there is a selected task, render details
  • otherwise, render a friendly placeholder

That is simpler and easier to maintain than toggling DOM nodes manually.

Step 10: Build the reactive form component properly

This is where many beginners need extra clarity.

The form component should:

  • create a typed reactive form
  • accept initial values for create or edit mode
  • validate title and other fields
  • emit a typed TaskDraft on save
  • emit cancel when the user backs out

A good teaching point here is that the form component should not own the whole feature workflow. It owns the form model and validation behavior. The feature state service or page decides what to do with the result.

What the form teaches

The form shows several Angular strengths at once:

  • structured state
  • validation rules
  • clean value extraction
  • reusable component boundary
  • stronger typing than ad hoc DOM reads

Step 11: Add routing even if the demo is small

Routing is still worth including.

A minimal setup might be:

  • root app with router outlet
  • redirect from empty path to /tasks
  • tasks route mapped to the board page

Why include routing in a small tutorial?

Because it teaches the right habit: route pages are architecture boundaries.

Without routing, beginners often end up thinking of the whole app as one giant page component.

Step 12: Write the templates with discipline

This is a crucial quality rule.

Templates should be readable and declarative.

Use them for:

  • interpolation
  • property binding
  • event binding
  • conditional rendering
  • list rendering

Do not use them for:

  • complicated data transformations
  • business rules
  • long chains of fallback logic
  • hidden side effects

One of the best migration improvements is moving complicated UI decisions into named computed values or methods with clear meaning.

Step 13: Handle empty, loading, and edge states honestly

A good tutorial should not only show the happy path.

Even a local demo app should think in terms of:

  • no tasks yet
  • no matching tasks after filtering
  • no selected task
  • invalid form submission
  • editing a task that was deleted

This is where Angular and TypeScript really help. Once you model state explicitly, these non-happy paths become easier to express clearly.

Step 14: Add project structure rules

For example:

  • src/app/models for domain and draft types
  • src/app/services for state and persistence
  • src/app/features/tasks for task feature components
  • route-level file near the feature
  • keep related files close together

Organization matters because beginners often underestimate how quickly projects become hard to navigate.

Step 15: Discuss performance as a design habit

Even a small app can teach good habits.

Performance-minded design here means:

  • use derived state instead of repeating expensive work everywhere
  • keep templates simple
  • track item identity when rendering lists
  • avoid needless global mutable state
  • keep feature boundaries clear

The lesson is not to over-optimize a tiny tutorial. The lesson is to make good structure the default.

Step 16: Discuss security and DOM rules

This is especially important for students coming from plain JavaScript.

New Angular developers should learn early:

  • avoid direct DOM manipulation unless truly necessary
  • avoid raw HTML injection patterns carried over from old apps
  • prefer Angular bindings and Angular’s safety model

This helps prevent many bad habits from migrating unchanged.

Step 17: Discuss testing strategy, even if you do not build every test in the tutorial

A thorough migration tutorial should explain what to test.

State service tests

  • filtering logic
  • selection logic
  • create/update/delete logic
  • derived stats

Component tests

  • toolbar emits expected events
  • list renders tasks correctly
  • form validation and submission behavior
  • details panel renders selected task and empty state correctly

Integration behavior

  • selecting a task updates the details panel
  • creating a task updates list and stats
  • deleting a selected task clears the details state

This matters because one promise of Angular + TypeScript is safer change. That promise becomes real when the architecture is testable.

Step 18: Compare the final Angular design with the original JavaScript design

Let us summarize the transformation.

Plain JavaScript version

  • manual DOM updates
  • global mutable state
  • imperative event wiring
  • runtime object assumptions
  • a blur between rendering, state, and business behavior

Angular version

  • component-based UI
  • explicit feature state service
  • signals and computed state
  • typed models and form payloads
  • reactive forms
  • route-level boundaries
  • clear communication contracts

This is the real value of the migration.

Step 19: The biggest beginner lesson

The hardest thing for amateurs is usually not Angular syntax.

It is learning to stop asking:

  • which function should call which other function?
  • which DOM node should I patch next?

And instead ask:

  • who owns this state?
  • what is the contract between these components?
  • is this source state or derived state?
  • should this behavior live in a component, a service, or a form model?

That is the real expert mindset.

Step 20: What a comprehensive migration checklist looks like

If I were teaching this as a real workshop, the final checklist would be:

  1. describe the current behavior completely
  2. define route boundaries
  3. draw the component tree
  4. classify component types
  5. design communication paths
  6. classify state layers
  7. separate source state from derived state
  8. define domain, draft, and filter types
  9. choose persistence boundaries
  10. choose form architecture
  11. implement the feature state service
  12. build presentational components
  13. build the form component
  14. connect routing
  15. review templates for readability
  16. review error, empty, and edge states
  17. review project structure
  18. review performance habits
  19. review DOM safety and security habits
  20. add tests or at least define the testing plan

That checklist is much more valuable than “convert file A, then file B, then file C.”

Closing thought

A good Angular migration is not a story about replacing one framework with another. It is a story about making a front-end application easier to reason about.

That is why the teaching example matters. When you compare the two Task Board versions side by side, the Angular version is not better because it uses more tools. It is better because responsibilities are clearer, contracts are explicit, and state has a home.

That is what beginners should learn first.