Separation of Concerns

Kind: principle

Layer: Structural Core

Aliases: SoC

Record: architecture:separation-of-concerns

Severity: mandatory

Scope: module, package, component, system

Canonical: Ontology

A design rule that parsing, business logic, persistence and presentation each live in their own part of the code.

Listed in Architecture principles, after Single Responsibility Principle (SRP) and before Do Not Repeat Yourself (DRY).

Requires

• Explicit Boundaries
• Abstraction

Reinforces

• Single Responsibility Principle (SRP)
• Modularity
• Layered Architecture

Enables

• Maintainability
• Replaceability

Conflicts with

• Cross-Cutting Leakage
• Mixed Layers

In tension with

• Over-Layering

Tensions

• Separation of Concerns / Over-Layering

Violated by

• Mixed Layers

Refactored by

• Extract Module
• Move Behavior to Its Owner
• Define Module Boundaries

Severity

• mandatory

Category

• Core Modular Design

Enforced by

• rules/eslint/closure-no-inline-exported-types.eslint.rule.ts
• rules/eslint/closure-types-centralized.eslint.rule.ts

Reinforced by

• Visitor Pattern
• Statecharts
• One Concern Per File

Linked from

• Placement is a grammar
• The layer spine
• Principles are typed
• The structural domain
• A concern is a component
• Domain Architecture
• Core Modular Design
• Behavioral Patterns
• Codebase / System Architecture Styles
• Taxonomy / Classification / Naming
• Core Modular Design
• Quality Attributes
• Severity levels
• The resolutions