tessl/npm-nodemon
Simple monitor script for use during development of a Node.js app.
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Nodemon
Nodemon is a development tool that automatically monitors Node.js applications and restarts them when file changes are detected in the directory. It serves as a drop-in replacement wrapper for the node command, requiring no changes to existing code or development workflows.
Package Information
- Package Name: nodemon
- Package Type: npm
- Language: JavaScript/TypeScript
- Installation:
npm install -g nodemonornpm install --save-dev nodemon
Core Imports
For programmatic usage (as a library):
const nodemon = require('nodemon');For CommonJS with destructuring:
const { config } = require('nodemon');For TypeScript (using CommonJS export pattern):
import nodemon = require('nodemon');
import type { NodemonSettings, NodemonConfig } from 'nodemon';
// Alternative ES module style (requires esModuleInterop)
import nodemon from 'nodemon';
import type { NodemonSettings, NodemonConfig } from 'nodemon';Basic Usage
CLI Usage
# Basic usage - monitors current directory and restarts on file changes
nodemon app.js
# With specific extensions
nodemon --ext js,json,ts app.js
# With custom watch directories
nodemon --watch src --watch config app.js
# With ignore patterns
nodemon --ignore test/ --ignore logs/ app.jsProgrammatic Usage
const nodemon = require('nodemon');
// Object configuration
nodemon({
script: 'app.js',
ext: 'js json ts',
watch: ['src/', 'config/'],
ignore: ['test/', 'logs/']
});
// String configuration (CLI-style)
nodemon('--ext js,json app.js');
// Event handling
nodemon.on('start', function () {
console.log('App has started');
}).on('quit', function () {
console.log('App has quit');
process.exit();
}).on('restart', function (files) {
console.log('App restarted due to: ', files);
});Architecture
Nodemon is built around several key components:
- Main Function: The primary
nodemon()function that can accept configuration objects or CLI-style strings - Event System: Built-in event emitter for monitoring application lifecycle (start, restart, quit, crash)
- File Monitoring: Uses Chokidar for efficient file system watching with ignore patterns and custom rules
- Process Management: Handles child process spawning, restarting, and signal forwarding
- Configuration System: Supports JSON config files, CLI arguments, and programmatic options
- CLI Interface: Command-line tool with comprehensive argument parsing and help system
Capabilities
Core API
The main nodemon function and essential control methods for starting, restarting, and managing monitored processes.
/**
* Main nodemon function - starts monitoring with given settings
* @param settings - Configuration object or CLI-style string
* @returns Nodemon instance for chaining
*/
function nodemon(settings: NodemonSettings | string): Nodemon;
interface Nodemon {
/** Manually restart the monitored process */
restart(): Nodemon;
/** Reset nodemon to clean state (useful for testing) */
reset(callback?: Function): Nodemon;
/** Reference to internal configuration */
config: NodemonSettings;
/** Dynamic stdout stream (available when stdout: false is configured) */
stdout?: NodeJS.ReadableStream;
/** Dynamic stderr stream (available when stdout: false is configured) */
stderr?: NodeJS.ReadableStream;
}Event System
Event emitter interface for monitoring application lifecycle and handling custom events.
interface NodemonEventListener {
/** Add event listener for nodemon events */
on(event: 'start' | 'crash' | 'readable', listener: () => void): Nodemon;
on(event: 'log', listener: (e: NodemonEventLog) => void): Nodemon;
on(event: 'stdout' | 'stderr', listener: (e: string) => void): Nodemon;
on(event: 'restart', listener: (e?: NodemonEventRestart) => void): Nodemon;
on(event: 'quit', listener: (e?: NodemonEventQuit) => void): Nodemon;
on(event: 'exit', listener: (e?: number) => void): Nodemon;
on(event: 'config:update', listener: (e?: NodemonEventConfig) => void): Nodemon;
}
type NodemonEventHandler = 'start' | 'crash' | 'exit' | 'quit' | 'restart' | 'config:update' | 'log' | 'readable' | 'stdout' | 'stderr';Configuration
Comprehensive configuration options for file watching, process execution, and monitoring behavior.
interface NodemonSettings extends NodemonConfig, NodemonExecOptions {
events?: Record<string, string>;
env?: Record<string, string>;
}
interface NodemonConfig {
restartable?: false | string;
colours?: boolean;
watch?: string[];
ignore?: string[];
ext?: string;
verbose?: boolean;
stdout?: boolean;
delay?: number;
// ... additional configuration options
}Types
Event Types
type NodemonEventHandler =
| 'start'
| 'crash'
| 'exit'
| 'quit'
| 'restart'
| 'config:update'
| 'log'
| 'readable'
| 'stdout'
| 'stderr';
interface NodemonEventLog {
/** Log level: detail, log, status, error, fail */
type: 'detail' | 'log' | 'status' | 'error' | 'fail';
/** Plain text message */
message: string;
/** Terminal escape codes with color and "[nodemon]" prefix */
colour: string;
}
interface NodemonEventRestart {
matched?: {
result: string[];
total: number;
};
}
type NodemonEventQuit = 143 | 130;Configuration Types
interface NodemonExecOptions {
script: string;
scriptPosition?: number;
args?: string[];
ext?: string;
exec?: string;
execArgs?: string[];
nodeArgs?: string[];
}
interface NodemonEventConfig {
run: boolean;
system: {
cwd: string;
};
required: boolean;
dirs: string[];
timeout: number;
options: NodemonConfig;
lastStarted: number;
loaded: string[];
load: (settings: NodemonSettings, ready: (config: NodemonEventConfig) => void) => void;
reset: () => void;
}- Workspace
- tessl
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- Public
- Created
- Last updated
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