noname/node_modules/options/lib/options.js

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2016-03-29 13:43:15 +00:00
/*!
* Copyright(c) 2011 Einar Otto Stangvik <einaros@gmail.com>
* MIT Licensed
*/
var fs = require('fs');
function Options(defaults) {
var internalValues = {};
var values = this.value = {};
Object.keys(defaults).forEach(function(key) {
internalValues[key] = defaults[key];
Object.defineProperty(values, key, {
get: function() { return internalValues[key]; },
configurable: false,
enumerable: true
});
});
this.reset = function() {
Object.keys(defaults).forEach(function(key) {
internalValues[key] = defaults[key];
});
return this;
};
this.merge = function(options, required) {
options = options || {};
if (Object.prototype.toString.call(required) === '[object Array]') {
var missing = [];
for (var i = 0, l = required.length; i < l; ++i) {
var key = required[i];
if (!(key in options)) {
missing.push(key);
}
}
if (missing.length > 0) {
if (missing.length > 1) {
throw new Error('options ' +
missing.slice(0, missing.length - 1).join(', ') + ' and ' +
missing[missing.length - 1] + ' must be defined');
}
else throw new Error('option ' + missing[0] + ' must be defined');
}
}
Object.keys(options).forEach(function(key) {
if (key in internalValues) {
internalValues[key] = options[key];
}
});
return this;
};
this.copy = function(keys) {
var obj = {};
Object.keys(defaults).forEach(function(key) {
if (keys.indexOf(key) !== -1) {
obj[key] = values[key];
}
});
return obj;
};
this.read = function(filename, cb) {
if (typeof cb == 'function') {
var self = this;
fs.readFile(filename, function(error, data) {
if (error) return cb(error);
var conf = JSON.parse(data);
self.merge(conf);
cb();
});
}
else {
var conf = JSON.parse(fs.readFileSync(filename));
this.merge(conf);
}
return this;
};
this.isDefined = function(key) {
return typeof values[key] != 'undefined';
};
this.isDefinedAndNonNull = function(key) {
return typeof values[key] != 'undefined' && values[key] !== null;
};
Object.freeze(values);
Object.freeze(this);
}
module.exports = Options;