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ML SystemPart 3: Chapter 10
CH.10 ~20 min

Code Quality

Validation, Errors, and ESLint.

ValidationESLintErrors
  • Implement built-in and custom validators in Mongoose schemas.
  • Create a centralized error-handling middleware in Express.
  • Configure ESLint rules to maintain consistent code style.

01 Validation & Error Handling Viz

Definition

Validation Middleware

A centralized error-handling middleware in Express that catches exceptions and returns appropriate HTTP status codes (e.g., 400 Bad Request).

Centralized Error Handling

Instead of duplicating try-catch blocks everywhere, delegate errors to a specialized middleware that analyzes error names and formats response messages.

02 Static Analysis & ESLint

  • **Standard Indentation**: Enforcing 2-space tabs.
  • **EqEqEq**: Requiring strict equality operators (=== and !==).
  • **Linebreaks**: Standardizing on Unix-style linebreaks.

Key Takeaways

  1. 1Enforce data integrity at the database level using Mongoose validators.
  2. 2Centralized error-handling middleware simplifies backend logic.
  3. 3ESLint ensures consistent code quality across the entire development team.

CH.10

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