Source: data/sources.js

  1. import {RegistryBase} from '../registry/base';
  2. import { ADAPTERS } from '../registry';
  4. /**
  5.  * Create and coordinate an ensemble of (namespaced) data adapter instances.
  6.  * This is the mechanism by which users tell a plot how to retrieve data for a specific plot: adapters are created
  7.  *  through this object rather than instantiating directly.
  8.  *
  9.  * @public
  10.  * @alias module:LocusZoom~DataSources
  11.  * @extends module:registry/base~RegistryBase
  12.  * @inheritDoc
  13.  */
  14. class DataSources extends RegistryBase {
  15.     /**
  16.      * @param {RegistryBase} [registry] Primarily used for unit testing. When creating sources by name, specify where to
  17.      *  find the registry of known sources.
  18.      */
  19.     constructor(registry) {
  20.         super();
  21.         // This both acts as a registry (of the instantiated sources for this plot), and references a registry
  22.         //   (to locate adapter classes by name, when creating from config)
  23.         this._registry = registry || ADAPTERS;
  24.     }
  26.     /**
  27.      * For data sources, there is a special behavior of "create item from config, then add"
  28.      * @param {String} namespace Uniquely identify this datasource
  29.      * @param {BaseAdapter|Array} item An instantiated datasource, or an array of arguments that can be used to
  30.      *   create a known datasource type.
  31.      * @param [override=false] Whether to allow existing sources to be redefined
  32.      * @return {DataSources} Most registries return the created instance, but this registry returns a reference to
  33.      *  itself (to support chaining)
  34.      */
  35.     add(namespace, item, override = false) {
  36.         if (this._registry.has(namespace)) {
  37.             throw new Error(`The namespace ${namespace} is already in use by another source`);
  38.         }
  40.         if (namespace.match(/[^A-Za-z0-9_]/)) {
  41.             throw new Error(`Data source namespace names can only contain alphanumeric characters or underscores. Invalid name: ${namespace}`);
  42.         }
  43.         if (Array.isArray(item)) {
  44.             const [type, options] = item;
  45.             item = this._registry.create(type, options);
  46.         }
  47.         // Each datasource in the chain should be aware of its assigned namespace
  48.         item.source_id = namespace;
  50.         super.add(namespace, item, override);
  51.         return this;
  52.     }
  53. }
  56. export default DataSources;