requirez/loader.js

module require loader with no cache and dir concat

'use strict';

const kit = require('./kit.js');

class Loader{
	
	/**
	 * @constructor
	 * @param {object} op
	 */
	constructor(op){
		this.config = {
			root: ''
			, extname: '.js'
			// , dirExtname: '/'
			, codeExtname: '.code'
			, forceUpdate: false
		};
		this.param = {};
		this.alias = {};
		this.cache = {};
		
		this._setConfig(op);
	}
	
	
	_setConfig(op){
		Object.assign(this.config, op);
		
		['param', 'alias'].forEach((key)=>{
			Object.assign(this[key], this.config[key]);
			delete this.config[key];
		});
		
		this.config.root = kit.toUnixPath(this.config.root || process.cwd(), 1);
	}
	
	
	/**
	 * 加载一个模块或从缓存中读取
	 * @param {string} name
	 */
	get(name){
		let path, rs;
		
		name = name == null ? '' : name.toString();
		
		//* parse param
		name = name.indexOf('{') === -1 ? name : kit.parseString(name, this.param);
		
		//* parse alias
		path = this.alias[name] || name;
		
		if(path && ['object', 'function'].indexOf(typeof path) > -1){
			return path;
		}
		
		//* get path
		path = kit.isAbsolutePath(path) ? path : this.config.root + path;
		
		//* get extname
		let extname = kit.extname(path);
		
		if(extname === this.config.codeExtname){
			path = kit.toUnixPath(path, 1);
			kit.concatDirFiles(path);
			path += 'index.js';
		}else if(extname === ''){
			path += this.config.extname;
		}
		
		//* is clear cache
		if(this.config.forceUpdate){
			delete this.cache[path];
			this.clear(path);
		}
		
		//* is cache exists
		if(path in this.cache){
			rs = this.cache[path];
		}else{
			rs = this.cache[path] = require(path);
		}
		
		return rs;
	}
	
	
	/**
	 * 清除缓存
	 * @param {string} id - module id
	 */
	clear(id){
		if(id == null){
			let key;
			for(key in require.cache){
				delete require.cache[key]
			}
		}else{
			id = id.charAt(1) !== ':' ? id : id.replace(/\//g, '\\');
			delete require.cache[id];
			// console.log('<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<')
			// console.log('clear cache', id)
			// console.log('>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>')
		}
	}
}

module.exports = Loader;