Solution: Construct a Form Schema Builder with Validation Rules

Explore how to use the Builder pattern to create a FormSchemaBuilder that assembles complex form schemas with validation rules. Understand how to enforce no duplicate fields, require completion of field setups, and chain methods fluently for scalable form handling in Node.js.

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Solution explanation
Revisit the problem statement

Solution explanation

Lines 2–6: We initialize FormSchemaBuilder with an empty fields object and state flags to track defined fields, the field currently being built, and whether a field is currently being constructed.
Lines 8–18: .addField() enforces that no duplicate fields are added and that only one field is being built at a time. It creates a new FieldBuilder and passes in the field context.
Lines 20–24: _finalizeField() is called by FieldBuilder.done() to register a field definition and reset the state.
Lines 26–31: .build() throws if ...

1.Introduction to Node.js Patterns

2.Factory Pattern: Generate Config-Driven Services Dynamically

3.Builder Pattern: Assemble Complex Objects with Fluent APIs

4.Decorator Pattern: Extend Behavior Without Modifying Core Logic

5.Adapter Pattern: Standardize Interface Across Dependencies

6.Proxy Pattern: Intercept and Control Access Transparently

7.Strategy Pattern: Swap Algorithms Based on Context

8.Wrapping Up

Solution: Construct a Form Schema Builder with Validation Rules

Solution explanation