0
# @loopback/build
1

2
@loopback/build is a comprehensive set of build tools and configurations specifically designed for LoopBack 4 and other TypeScript projects. It provides command-line utilities for TypeScript compilation, code linting, formatting, testing, and coverage, along with programmatic APIs for integration into build workflows.
3

4
## Package Information
5

6
- **Package Name**: @loopback/build
7
- **Package Type**: npm
8
- **Language**: TypeScript/JavaScript
9
- **Installation**: `npm install @loopback/build --save-dev`
10

11
## Core Imports
12

13
```typescript
14
import { 
15
  tsc,
16
  prettier,
17
  mocha,
18
  nyc,
19
  clean,
20
  runCLI, 
21
  runShell, 
22
  mergeMochaConfigs, 
23
  typeScriptPath 
24
} from "@loopback/build";
25
```
26

27
For CommonJS:
28

29
```javascript
30
const { 
31
  tsc,
32
  prettier,
33
  mocha,
34
  nyc,
35
  clean,
36
  runCLI, 
37
  runShell, 
38
  mergeMochaConfigs, 
39
  typeScriptPath 
40
} = require("@loopback/build");
41
```
42

43
## Basic Usage
44

45
```json
46
{
47
  "scripts": {
48
    "build": "lb-tsc",
49
    "build:watch": "lb-tsc --watch",
50
    "clean": "lb-clean",
51
    "lint": "npm run prettier:check && npm run eslint",
52
    "lint:fix": "npm run prettier:fix && npm run eslint:fix",
53
    "prettier:cli": "lb-prettier \"**/*.ts\" \"**/*.js\"",
54
    "prettier:check": "npm run prettier:cli -- -l",
55
    "prettier:fix": "npm run prettier:cli -- --write",
56
    "eslint": "lb-eslint --report-unused-disable-directives .",
57
    "eslint:fix": "npm run eslint -- --fix",
58
    "pretest": "npm run clean && npm run build",
59
    "test": "lb-mocha \"dist/__tests__\"",
60
    "posttest": "npm run lint"
61
  }
62
}
63
```
64

65
## Architecture
66

67
@loopback/build is built around several key components:
68

69
- **CLI Tools**: Command-line executables (`lb-tsc`, `lb-eslint`, etc.) that wrap popular development tools
70
- **Programmatic API**: Node.js functions for programmatic access to build operations
71
- **Utility Functions**: Helper functions for CLI resolution, configuration loading, and process management
72
- **Default Configurations**: Pre-configured settings for TypeScript, ESLint, Prettier, Mocha, and NYC
73
- **Console Log Detection**: Advanced Mocha integration that detects and fails on unexpected console output
74

75
## Capabilities
76

77
### TypeScript Compilation
78

79
TypeScript compiler wrapper with support for ttypescript plugins, resource copying, and automatic configuration generation.
80

81
```typescript { .api }
82
function tsc(argv: string[], options?: RunOptions): ChildProcess | string;
83
```
84

85
[TypeScript Compilation](./typescript-compilation.md)
86

87
### Code Linting
88

89
ESLint integration with automatic configuration discovery and LoopBack-specific rules through the `lb-eslint` CLI command.
90

91
[Code Linting](./code-linting.md)
92

93
### Code Formatting
94

95
Prettier integration with configuration discovery and file pattern support.
96

97
```typescript { .api }
98
function prettier(argv: string[], options?: RunOptions): ChildProcess | string;
99
```
100

101
[Code Formatting](./code-formatting.md)
102

103
### Test Execution
104

105
Mocha test runner with console log detection, configuration merging, and enhanced error reporting.
106

107
```typescript { .api }
108
function mocha(argv: string[], options?: RunOptions): ChildProcess | string;
109
```
110

111
[Test Execution](./test-execution.md)
112

113
### Code Coverage
114

115
NYC code coverage wrapper for generating test coverage reports.
116

117
```typescript { .api }
118
function nyc(argv: string[], options?: RunOptions): ChildProcess | string;
119
```
120

121
[Code Coverage](./code-coverage.md)
122

123
### File Cleanup
124

125
Utility for safely removing build artifacts and temporary files.
126

127
```typescript { .api }
128
function clean(argv: string[], options?: RunOptions): string;
129
```
130

131
[File Cleanup](./file-cleanup.md)
132

133
### Process Management
134

135
Core utilities for running CLI commands and managing child processes.
136

137
```typescript { .api }
138
function runCLI(
139
  cli: string,
140
  args: string[],
141
  options?: RunCLIOptions
142
): ChildProcess | string;
143

144
function runShell(
145
  command: string,
146
  args: string[],
147
  options?: RunShellOptions
148
): ChildProcess | string;
149
```
150

151
[Process Management](./process-management.md)
152

153
## Types
154

155
```typescript { .api }
156
import { ChildProcess } from "child_process";
157

158
interface RunOptions {
159
  dryRun?: boolean;
160
  cwd?: string;
161
  resolveFromProjectFirst?: boolean;
162
}
163

164
interface RunCLIOptions extends RunOptions {
165
  nodeArgs?: string[];
166
}
167

168
interface RunShellOptions extends RunOptions {
169
  stdio?: string;
170
  env?: Record<string, string>;
171
  shell?: boolean;
172
}
173

174
interface MochaConfig {
175
  timeout?: number;
176
  require?: string | string[];
177
  [key: string]: any;
178
}
179
```