Effective TypeScript: 62 Specific Ways to Improve Your TypeScript

Inhaltsverzeichnis des Buches

• Preface
• Who This Book Is For
• Why I Wrote This Book
• How This Book Is Organized
• Conventions in TypeScript Code Samples
• Typographical Conventions Used in This Book
• Using Code Examples
• O’Reilly Online Learning
• How to Contact Us
• Acknowledgments
• 1. Getting to Know TypeScript
• Item 1: Understand the Relationship Between TypeScript and JavaScript
• Item 2: Know Which TypeScript Options You’re Using
• Item 3: Understand That Code Generation Is Independent of Types
• Item 4: Get Comfortable with Structural Typing
• Item 5: Limit Use of the any Type
• 2. TypeScript’s Type System
• Item 6: Use Your Editor to Interrogate and Explore the Type System
• Item 7: Think of Types as Sets of Values
• Item 8: Know How to Tell Whether a Symbol Is in the Type Space or Value Space
• Item 9: Prefer Type Declarations to Type Assertions
• Item 10: Avoid Object Wrapper Types (String, Number, Boolean, Symbol, BigInt)
• Item 11: Recognize the Limits of Excess Property Checking
• Item 12: Apply Types to Entire Function Expressions When Possible
• Item 13: Know the Differences Between type and interface
• Item 14: Use Type Operations and Generics to Avoid Repeating Yourself
• Item 15: Use Index Signatures for Dynamic Data
• Item 16: Prefer Arrays, Tuples, and ArrayLike to number Index Signatures
• Item 17: Use readonly to Avoid Errors Associated with Mutation
• Item 18: Use Mapped Types to Keep Values in Sync
• 3. Type Inference
• Item 19: Avoid Cluttering Your Code with Inferable Types
• Item 20: Use Different Variables for Different Types
• Item 21: Understand Type Widening
• Item 22: Understand Type Narrowing
• Item 23: Create Objects All at Once
• Item 24: Be Consistent in Your Use of Aliases
• Item 25: Use async Functions Instead of Callbacks for Asynchronous Code
• Item 26: Understand How Context Is Used in Type Inference
• Item 27: Use Functional Constructs and Libraries to Help Types Flow
• 4. Type Design
• Item 28: Prefer Types That Always Represent Valid States
• Item 29: Be Liberal in What You Accept and Strict in What You Produce
• Item 30: Don’t Repeat Type Information in Documentation
• Item 31: Push Null Values to the Perimeter of Your Types
• Item 32: Prefer Unions of Interfaces to Interfaces of Unions
• Item 33: Prefer More Precise Alternatives to String Types
• Item 34: Prefer Incomplete Types to Inaccurate Types
• Item 35: Generate Types from APIs and Specs, Not Data
• Item 36: Name Types Using the Language of Your Problem Domain
• Item 37: Consider “Brands” for Nominal Typing
• 5. Working with any
• Item 38: Use the Narrowest Possible Scope for any Types
• Item 39: Prefer More Precise Variants of any to Plain any
• Item 40: Hide Unsafe Type Assertions in Well-Typed Functions
• Item 41: Understand Evolving any
• Item 42: Use unknown Instead of any for Values with an Unknown Type
• Item 43: Prefer Type-Safe Approaches to Monkey Patching
• Item 44: Track Your Type Coverage to Prevent Regressions in Type Safety
• 6. Types Declarations and @types
• Item 45: Put TypeScript and @types in devDependencies
• Item 46: Understand the Three Versions Involved in Type Declarations
• Item 47: Export All Types That Appear in Public APIs
• Item 48: Use TSDoc for API Comments
• Item 49: Provide a Type for this in Callbacks
• Item 50: Prefer Conditional Types to Overloaded Declarations
• Item 51: Mirror Types to Sever Dependencies
• Item 52: Be Aware of the Pitfalls of Testing Types
• 7. Writing and Running Your Code
• Item 53: Prefer ECMAScript Features to TypeScript Features
• Item 54: Know How to Iterate Over Objects
• Item 55: Understand the DOM hierarchy
• Item 56: Don’t Rely on Private to Hide Information
• Item 57: Use Source Maps to Debug TypeScript
• 8. Migrating to TypeScript
• Item 58: Write Modern JavaScript
• Item 59: Use @ts-check and JSDoc to Experiment with TypeScript
• Item 60: Use allowJs to Mix TypeScript and JavaScript
• Item 61: Convert Module by Module Up Your Dependency Graph
• Item 62: Don’t Consider Migration Complete Until You Enable noImplicitAny
• Index