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Revamp DI module

master
Mohammad Fares 4 years ago
parent
commit
2cc0601ed0
  1. 147
      di.js

147
di.js

@ -1,17 +1,154 @@
/**
* Dependency Injection
* Dependency injection
*
* @author Mohammad Fares <faressoft.com@gmail.com>
*/
var path = require('path'),
_ = require('lodash');
/**
* Dependency injection
*/
function DI() {
/**
* Injected dependecies
* @type {Object}
*/
this._dependencies = {};
/**
* A wrapper proxy object to set traps
* @type {Proxy}
*/
this._proxy = new Proxy(this, {
get: this.getHandler,
set: this.setHandler
});
return this._proxy;
}
/**
* Set/Add a dependency
* Trap for getting a property value
*
* @param {Object} target
* @param {String} key
* @return {*}
*/
DI.prototype.getHandler = function(target, key) {
if (key in target) {
return target[key];
}
if (key in target._dependencies) {
return target._dependencies[key];
}
};
/**
* Trap for setting a property value
*
* @param {Object} target
* @param {String} key
* @param {*} value
* @return {*}
*/
DI.prototype.setHandler = function(target, key, value) {
if (key in target) {
throw new Error(`It is not allowed to set '${key}'`);
}
target._dependencies[key] = value;
return true;
};
/**
* Require and set a package
*
* - Require the module
* - Add the module as depndency
* - Format the key as
* - Convert the moduleName to camelCase
* - Remove the extension
* - Resolve third party packages as the native `require`.
* - Resolve our own scripts with paths relative to
* the app's root path `require`.
*
* @param {String} moduleName
* @param {String} key (Optional) (Default: the moduleName camel cased)
*/
DI.prototype.require = function(moduleName, key) {
var parsedModuleName = path.parse(moduleName);
// Default value for key
if (typeof key == 'undefined') {
key = _.camelCase(parsedModuleName.name);
}
// Is not a third party package
if (parsedModuleName.dir != '') {
// Resolve the path to an absolute path
moduleName = path.resolve(this._getAppRootPath(), moduleName);
}
this._dependencies[key] = require(moduleName);
};
/**
* Inject a dependency
*
* @param {String} key
* @param {Object} value
* @param {*} value
*/
DI.prototype.set = function(key, value) {
this[key] = value;
};
/**
* Get an injected dependency
*
* @param {String} key
* @return {*}
*/
module.exports.set = function(key, value) {
DI.prototype.get = function(key) {
module.exports[key] = value;
return this[key];
};
/**
* Get the root path of the app
*
* - Follow the module.parent.parent... etc until null
*
* @return {String}
*/
DI.prototype._getAppRootPath = function() {
var parent = module.parent;
while (parent.parent) {
parent = parent.parent;
}
return path.dirname(parent.filename);
};
module.exports = DI;
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