Source: ConfigResolver.js

  1. /**
  2.  * The Config Resolver is the central manager for configurations.
  3.  * It offers the functionality to resolve configuration entries based on the injected config path.
  4.  *
  5.  * @author Wolfgang Felbermeier (@f3lang)
  6.  */
  7. class ConfigResolver {
  9. 	constructor(configs) {
  10. 		this.configs = configs || {};
  11. 		this.cache = {};
  12. 	}
  14. 	/**
  15. 	 * Adds a new configuration to the collection
  16. 	 * @param configuration The configuration object
  17. 	 * @param root The configuration root name
  18. 	 */
  19. 	addConfiguration(configuration, root) {
  20. 		this.configs[root] = configuration;
  21. 	}
  23. 	/**
  24. 	 * Returns a configuration entry of the available configurations
  25. 	 * @param root The configuration root to look in
  26. 	 * @param path The path of the configuration to return
  27. 	 * @return {*}
  28. 	 */
  29. 	getConfig(root, path) {
  30. 		if (root === '' && path === '') {
  31. 			return this.configs;
  32. 		}
  33. 		if (this.cache[root + ":" + path]) {
  34. 			return this.cache[root + ":" + path]
  35. 		}
  36. 		if (!this.configs[root]) {
  37. 			throw new Error('Configuration root "' + root + '" does not exist');
  38. 		}
  39. 		if (path === "" || path === ".") {
  40. 			return this.configs[root];
  41. 		}
  42. 		try {
  43. 			let property = this._getProperty(this.configs[root], path.split('.'));
  44. 			this.cache[root + ":" + path] = property;
  45. 			return property;
  46. 		} catch (e) {
  47. 			throw new Error('Configuration path "' + path + '" does not exist in configuration root "' + root + '"');
  48. 		}
  49. 	}
  51. 	/**
  52. 	 * Returns the next available property of obj.
  53. 	 * e.g.:
  54. 	 * Your obj:
  55. 	 * {
  56. 	 * 		banana: {
  57. 	 * 			fruit: {
  58. 	 * 				price: 1
  59. 	 * 			}
  60. 	 * 		}
  61. 	 * }
  62. 	 * and your path will be ['banana', 'fruit', 'price']
  63. 	 * Then this function will return 1
  64. 	 *
  65. 	 * @param obj
  66. 	 * @param propertyPathArray
  67. 	 * @private
  68. 	 */
  69. 	_getProperty(obj, propertyPathArray) {
  70. 		if (propertyPathArray.length === 1) {
  71. 			return obj[propertyPathArray[0]];
  72. 		} else {
  73. 			return this._getProperty(obj[propertyPathArray.shift()], propertyPathArray);
  74. 		}
  75. 	}
  77. }
  79. module.exports = ConfigResolver;
  80. module.exports.inject = ['config::'];