src/lens_factory.js

  1. import CCCLens from './ccc_lens.js';
  2. import { DEFAULT_FACTORY as jsContainers } from './js_container_factory.js';
  4. /**
  5.  * @interface ContainerFactory
  6.  * @see Factory
  7.  */
  9. /**
  10.  * @function ContainerFactory#construct
  11.  * @summary Construct a missing container
  12.  * @param {Array} keys  The keys up to and including the one indexing into the missing container
  13.  * @returns {*} The missing container
  14.  */
  16. class LensFactory {
  17.   /**
  18.    * @constructs Factory
  19.    * @summary A factory for Lens-derived objects with customized container construction
  20.    * @param {Object} spec
  21.    * @param {ContainerFactory} spec.containerFactory  Factory for containers, used by [Lenses]{@link Lens} created by this Factory, invoked when modify-cloning missing containers in subject data
  22.    * 
  23.    * @description
  24.    * When POD container types (Object and Array) are not the desired types to 
  25.    * construct in a clone -- as with use of immutable containers -- this class
  26.    * can be used to build lenses that *do* build the desired types of objects.
  27.    * 
  28.    * This class is often used in conjunction with a JsContainerFactory object
  29.    * implementing the container factory.
  30.    */
  31.   constructor({containerFactory = jsContainers} = {}) {
  32.     this.containerFactory = containerFactory;
  33.   }
  34.   
  35.   /**
  36.    * Construct a lens through the factory
  37.    * @param {...*} key  A key of the customized lens type
  38.    * @returns {Lens}  A lens with customized container creation behavior
  39.    */
  40.   lens(...keys) {
  41.     const result = new CCCLens(...keys);
  42.     result._containerFactory = this.containerFactory;
  43.     return result;
  44.   }
  45. }
  47. export default LensFactory;