Angular - 3 2 Planning an application

Before writing a single line of code, we sit down and plan the structure of the application. Sketching the future component tree and listing the data we are going to handle takes only a few minutes but pays back massively during implementation. Plans are rarely perfect: components will be added, merged or moved as we go, yet starting with a solid foundation prevents the kind of cargo-cult coding that spirals out of control.

Every Angular application starts with a single root container — the AppComponent. Think of it as a wardrobe holding all the drawers: each feature lives in its own drawer, but they are all stored in the same root. Because the app has two distinct sections (shopping list and recipe book) it makes sense to introduce a dedicated header component that handles the navigation between them. The header will later hold a small dropdown to save and load data from the server, so isolating it as its own component is the right call.

Components we will need

• HeaderComponent — navigation between the two sections and a management dropdown.
• ShoppingListComponent + ShoppingEditComponent — list of ingredients and the edit form to add or update items.
• RecipesComponent wrapping RecipeListComponent, RecipeItemComponent and RecipeDetailComponent — the master/detail recipe view.

Each of these components is responsible for one job: displaying a list, showing details, editing a single entry. Keeping them small and focused makes them easier to test and reuse. Splitting can always go deeper, or be merged, depending on how the implementation feels.

The last thing to think about up front is the data model. The application clearly needs an Ingredient class (with a name and an amount) shared between recipes and the shopping list, and a Recipe class with a title, a description, an image and a list of ingredients. Defining these classes early gives every component a clear contract for the data it produces or consumes, which becomes critical the moment components start exchanging information through services. With this rough plan in hand we can finally jump into the next lesson and create the project itself.