Template System

/**
 * Template variables available during project creation
 */
interface TemplateVariables {
  name: string;           // Project display name (e.g., "My Awesome Project")
  npmname: string;        // NPM package name (e.g., "@company/my-project")  
  umdname: string;        // UMD global variable name (e.g., "MyProject")
  username: string;       // GitHub username (e.g., "johndoe")
  type: 'js' | 'ts';     // Template type selection
  manager: 'npm' | null; // Package manager preference
  version: string;        // CLI version used to create project
  pathname: string;       // Directory name to create
}

// Template syntax (EJS-compatible):
// <%=variable%>           - Output variable value with HTML escaping
// <%-variable%>           - Output variable value without escaping  
// <% if (condition) { %>  - Conditional blocks
// <% } %>                 - End conditional
// <% for (var i=0; i<items.length; i++) { %> - Loop constructs
// <% } %>                 - End loop

// In template file (package.json.tmpl):
{
  "name": "<%=npmname%>",
  "version": "1.0.0",
  "description": "<%=name%> - Generated by @js-lib/cli",
  "author": "<%=username%>",
  "repository": {
    "type": "git", 
    "url": "git://github.com/<%=username%>/<%=name%>.git"
  },
  "main": "dist/<%=umdname%>.cjs.js",
  "module": "dist/<%=umdname%>.esm.js"
}

// In template file (README.md.tmpl):
# [<%=name%>](https://github.com/<%=username%>/<%=name%>)

<% if (type === 'ts') { %>
This project is written in TypeScript for better type safety.
<% } else { %>
This project is written in JavaScript.
<% } %>

## Installation

```bash
npm install <%=npmname%>

### JavaScript Template Structure

The JavaScript template (`module-js`) provides a complete project structure with modern tooling.

```javascript { .api }
// JavaScript template files include:
interface JavaScriptTemplate {
  // Configuration files
  'jslib.json.tmpl': string;           // Project metadata
  'package.json.tmpl': string;         // NPM package configuration
  'rollup.config.js.tmpl': string;     // Build configuration
  '.eslintrc.js.tmpl': string;         // Linting rules
  
  // Documentation templates  
  'README.md.tmpl': string;            // English README
  'README.zh-CN.md.tmpl': string;      // Chinese README
  'CHANGELOG.md.tmpl': string;         // Change log
  'license.tmpl': string;              // MIT license
  
  // Source code templates
  'src/index.js.tmpl': string;         // Main source file
  'test/test.js.tmpl': string;         // Unit tests
  'demo/demo-node.js.tmpl': string;    // Node.js demo
  
  // Build and CI templates
  '.github/workflows/ci.yml.tmpl': string; // GitHub Actions
  'build-rollup.cjs.tmpl': string;     // Rollup CommonJS config
  'commitlint.config.js.tmpl': string; // Commit linting
}

// Generated project structure:
project-name/
├── src/              # Source code (ES6+)
├── test/             # Unit tests (Mocha)
├── demo/             # Usage examples  
├── dist/             # Compiled output
├── .github/          # CI/CD workflows
├── package.json      # NPM configuration
├── rollup.config.js  # Build configuration
├── .eslintrc.js      # Code quality rules
├── jslib.json        # Project metadata
└── README.md         # Documentation

// TypeScript template files include:
interface TypeScriptTemplate {
  // Additional TypeScript-specific files
  'tsconfig.json.tmpl': string;        // TypeScript configuration
  'src/index.ts.tmpl': string;         // TypeScript source file
  'test/test.ts.tmpl': string;         // TypeScript unit tests
  'typings/index.d.ts.tmpl': string;   // Type declarations
  
  // Same structure as JavaScript template but with TypeScript support
  // All .js files become .ts files with proper type annotations
}

// Generated TypeScript project includes:
// - Full TypeScript compilation pipeline
// - Type declaration generation (.d.ts files)
// - TypeScript-aware testing setup
// - ESLint with TypeScript parser
// - Source maps for debugging

// Package.json generation
{
  "name": "<%=npmname%>",
  "version": "1.0.0", 
  "main": "dist/<%=umdname%>.cjs.js",
  "module": "dist/<%=umdname%>.esm.js",
  "browser": "dist/<%=umdname%>.js",
  "author": "<%=username%>",
  "repository": {
    "url": "git://github.com/<%=username%>/<%=name%>.git"
  }
}

// README generation with conditional content
# [<%=name%>](https://github.com/<%=username%>/<%=name%>)

<% if (type === 'ts') { %>
[![TypeScript](https://img.shields.io/badge/TypeScript-ready-blue.svg)](https://www.typescriptlang.org/)
<% } %>

## Installation

```bash
npm install <%=npmname%>

import <%=umdname%> from '<%=npmname%>';
<% } else { %>
```javascript  
const <%=umdname%> = require('<%=npmname%>');
<% } %>

// Your code here

### Template Processing Engine

The template system is built on the `template_js` library providing powerful text processing.

```javascript { .api }
/**
 * Template processing features:
 */
interface TemplateEngine {
  // Variable interpolation
  variableSubstitution: true;     // <%=variable%> syntax
  htmlEscaping: true;             // Automatic HTML escaping
  rawOutput: true;                // <%-variable%> for unescaped output
  
  // Control structures  
  conditionals: true;             // <% if/else/endif %>
  loops: true;                    // <% for/while %>
  javascript: true;               // <% arbitrary JavaScript %>
  
  // Advanced features
  includes: false;                // Template inclusion (not used)
  filters: false;                 // Output filters (not used)
  helpers: false;                 // Custom helper functions (not used)
}

// Processing workflow:
// 1. Read .tmpl file from template directory
// 2. Apply variable substitution using provided data
// 3. Execute any embedded JavaScript logic
// 4. Write processed content to destination file
// 5. Remove .tmpl extension from destination filename

// Extended template data can include:
const customTemplateData = {
  // Standard variables
  name: 'my-project',
  npmname: '@company/my-project', 
  umdname: 'MyProject',
  username: 'johndoe',
  type: 'ts',
  version: '3.0.6',
  
  // Custom additions
  description: 'My awesome project description',
  keywords: ['javascript', 'library', 'utility'],
  license: 'MIT',
  year: new Date().getFullYear(),
  dependencies: {
    'lodash': '^4.17.21'
  }
};

# Template files must use .tmpl extension
package.json.tmpl      # Becomes package.json
README.md.tmpl         # Becomes README.md  
src/index.js.tmpl      # Becomes src/index.js
.eslintrc.js.tmpl      # Becomes .eslintrc.js

# Directory structure is preserved
template/base/src/index.js.tmpl  → project/src/index.js
template/base/test/test.js.tmpl  → project/test/test.js

// Template data structure passed to all templates
interface ProjectTemplateData {
  pathname: string;    // Directory name for the project
  name: string;        // Human-readable project name
  npmname: string;     // NPM package name (may include scope)
  umdname: string;     // Global variable name for UMD builds
  username: string;    // GitHub username for repository URLs
  type: 'js' | 'ts';  // Template type selection
  manager: 'npm' | null; // Package manager choice
  version: string;     // CLI version that created the project
}

// Template processing options
interface TemplateOptions {
  cover?: boolean;     // Whether to overwrite existing files (default: true)
  encoding?: string;   // File encoding (default: 'utf8')
}

// Template file structure
interface TemplateFile {
  path: string;        // Relative path within template directory
  content: string;     // Template content with placeholders
  destination: string; // Output path (without .tmpl extension)
}