Beattie-Hood Ben / Битти-Худ Бен - Modern TypeScript: A Practical Guide to Accelerate Your Development Velocity / Современный TypeScript: Практическое руководство по ускорению вашей разработки [2023, PDF, ENG]

Примеры страниц

Оглавление

About the Author ................................................................................................... ix
About the Technical Reviewer .................................................................................. xi
Chapter 1: How Typescript Came to Be ..................................................................... 1
lntroduction ........................................................................................................... 1
History .................................................................................................................. 1
The Problem ........................................................................................................... 5
Scalable Velocity ..................................................................................................... 6
Testing Allows Scale ................................................................................................ 6
Docs Allow Scale ..................................................................................................... 7
Types Provide Both Testing and Docs ......................................................................... 7
Summary ............................................................................................................... 8
Chapter 2: Getting Started with the Developer Experience ............................................ 9
Introduction ........................................................................................................... 9
Environment and IDE ............................................................................................. 10
No-Frills Typescript Setup ....................................................................................... 10
Debugging Typescript ............................................................................................. 11
Typescript Within a More Realistic Setup ................................................................... 13
Honorable Mentions ............................................................................................... 15
Summary ............................................................................................................. 16
Chapter 3: Typescript Basics ................................................................................... 19
Introduction ......................................................................................................... 19
Structural Typing .................................................................................................. 20
JavaScript Types Are Structural Contracts ................................................................ 24
Adding Explicit Types to JavaScript .......................................................................... 25
Optionality ........................................................................................................... 31
All The Sugar ....................................................................................................... 33
Array and Object Destructuring, Spread, and Rest ..................................................... 33
Async ................................................................................................................. 37
Generators .......................................................................................................... 38
Inferred Types ..................................................................................................... 39
Types, Automagically ............................................................................................ 39
Type Widening and Narrowing ................................................................................ 43
Auto-narrowing, but Not Too Much .......................................................................... 45
Type Assertions .................................................................................................... 49
Compile-Time Assertions ........................................................................................ 50
Runtime Assertions ............................................................................................... 59
any and unknown Keywords ................................................................................... 65
Caution: Handle with Care ...................................................................................... 68
Parameterized Values ............................................................................................. 69
Index Signatures ................................................................................................... 71
Function Signatures ............................................................................................... 72
Constructor Signatures ........................................................................................... 74
A New Mental Model .............................................................................................. 75
Summary ............................................................................................................. 78
Chapter 4: Classes ................................................................................................ 81
Introduction ......................................................................................................... 81
Classes ................................................................................................................ 82
Constructors ........................................................................................................ 82
Access Modifiers ................................................................................................... 82
Fields .................................................................................................................. 83
Getters and Setters .............................................................................................. 86
Methods .............................................................................................................. 87
Inheritance .......................................................................................................... 87
Implements ......................................................................................................... 89
Static Modifier ..................................................................................................... 92
Warning 1: Classes Are Not Types .......................................................................... 93
Warning 2: Classes Can Cause Scope Bleed ............................................................ 95
Summary ........................................................................................................... 98
Chapter 5: Computed Types ................................................................................. 101
Introduction ....................................................................................................... 101
Type Aliases ...................................................................................................... 102
Using Type Aliases ............................................................................................. 105
Union Types ....................................................................................................... 107
Intersection Types ............................................................................................. 115
Generic Types ................................................................................................... 118
Type Parameters ............................................................................................... 118
con st Modifier on Generic Parameters ................................................................. 122
Generic Constraints .......................................................................................... 123
Inferred Type Keywords .................................................................................... 125
typeof Type Inference Keyword ......................................................................... 126
keyof Type Inference Keyword .......................................................................... 128
Where's the valueof Type Inference Keyword? .................................................... 131
Utility Types .................................................................................................. 132
Record ...................................................................................... 132
Pick< Type, Keys> ........................................................................................ 133
Omit ........................................................................................ 135
Partial< Type> ............................................................................................. 138
Required .......................................................................................... 139
Readonly ......................................................................................... 140
Exclude .................................................................................. 144
Extract ................................................................................... 147
Parameters ......................................................................... 147
ConstructorParameters ............................................................ 149
ReturnType ......................................................................... 150
Conditional Types ....................................................................................... 152
extends Keyword ........................................................................................ 153
infer Keyword ............................................................................................ 155
Extracting Inferred Types ............................................................................. 159
Distributive and Nondistributive Conditional Types ........................................... 161
Conditional Types via Property Accessors ......................................................... 163
Mapped Types .............................................................................................. 164
Changing the Type of Fields ............................................................................ 164
Adding and Removing Fields ............................................................................ 169
Renaming Fields .............................................................................................. 171
Recursive Types ................................................................................................ 172
Recursion Within an ObjectType ........................................................................... 172
Recursion over a Tuple Type ................................................................................ 174
Template Literals ................................................................................................ 177
Summary ........................................................................................................... 179
Chapter 6: Advanced Usage .................................................................................. 181
Introduction ....................................................................................................... 181
Expect and lsEqual .............................................................................................. 182
Compute ............................................................................................................ 185
JsonOf ............................................................................................................... 189
Flatten ............................................................................................................... 196
UrlParameters .................................................................................................... 198
Uri Parameters with Optional Pa rams .................................................................... 201
Further Reading .................................................................................................. 208
Summary ........................................................................................................... 209
Chapter 7: Performance ...................................................................................... 213
Introduction ..................................................................................................... 213
Reducing lnline Types ....................................................................................... 214
Reducing Inferred Types ................................................................................... 217
In line Caching Using Conditional Types ............................................................. 221
Reduce Intersections ....................................................................................... 223
Reduce Union Types ........................................................................................ 225
Partition Using Packages and Projects ............................................................... 225
Partitioning Using Packages ............................................................................. 225
Partitioning Using Projects ............................................................................... 226
Other Performance Tweaks ............................................................................... 228
Debugging Performance Issues .......................................................................... 228
Using the @typescript/analyze-trace NPM Package ................................................. 229
Using a Trace Viewer Within Your Browser ............................................................. 230
Summary ........................................................................................................... 231
Chapter B: Build .................................................................................................. 235
Introduction ....................................................................................................... 235
Compiler Options ............................................................................................... 236
Recommended tsconfig.json Settings .................................................................. 238
Other Options ................................................................................................. 246
Linting ........................................................................................................... 247
Installing ESLint. ............................................................................................ 247
Ideal Ruleset. ................................................................................................ 248
Additional Strict Errors ................................................................................... 253
Additional Strict Warnings .............................................................................. 257
Removed Rules ............................................................................................ 261
Further Rules ............................................................................................... 267
JSX/TSX ...................................................................................................... 267
Modules ...................................................................................................... 274
Module Types Explained ................................................................................ 274
Exports and Imports .................................................................................... 278
How Typescript Resolves Modules .................................................................. 282
Summary ................................................................................................... 286
Chapter 9: Wrap Up ..................................................................................... 289
Index ......................................................................................................... 291