node.js の project のための config ファイルを管理する.

conf.js

/*jslint indent: 4*/
/*jslint node: true */
'use strict';

var fs = require('fs'),
    conf = {},
    conf_dir = '/config';

conf.home = process.env.NODE_HOME || '.';
conf.env = process.env.NODE_ENV || 'development';

conf = extend(conf, readJSON(conf.home + conf_dir + '/config.json'));

if (fs.existsSync(conf.home + conf_dir + '/config_' + conf.env + '.json')) {
    conf = extend(conf, readJSON(conf.home + conf_dir + '/config_' + conf.env + '.json'));
}

if (fs.existsSync(conf.home + conf_dir + '/config_local.json')) {
    conf = extend(conf, readJSON(conf.home + conf_dir + '/config_local.json'));
}

module.exports = conf;

function readJSON(path) {
    return JSON.parse(fs.readFileSync(path, 'UTF-8'));
}

function extend(target, obj) {
    var result,
        obj_keys = Object.keys(obj);
    
    result = Object.keys(target).length ? clone(target) : {};

    obj_keys.forEach(function (key) {
        Object.defineProperty(result, key, Object.getOwnPropertyDescriptor(obj, key));
    });

    return result;
}

function clone(obj) {
    return extend({}, obj);
}