Standard libraries that lift up your code.
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import {Canonical} from './Canonical'
import {Singleton} from '../di'
import {Maybe} from '../util'
/**
* Error throw when a duplicate canonical key is registered.
* @extends Error
*/
export class DuplicateResolverKeyError extends Error {
constructor(key: string) {
super(`There is already a canonical unit with the scope ${key} registered.`)
}
}
/**
* Error throw when a key that isn't registered with the service.
* @extends Error
*/
export class NoSuchCanonicalResolverKeyError extends Error {
constructor(key: string) {
super(`There is no such canonical unit with the scope ${key} registered.`)
}
}
/**
* Service used to access various canonical resources.
*/
@Singleton()
export class Canon {
/**
* The resources registered with this service. Map of canonical service name
* to canonical service instance.
* @type object
*/
protected resources: { [key: string]: Canonical<any> } = {}
/**
* Get a canonical resource by its name key.
* @param {string} key
* @return Canonical
*/
resource<T>(key: string): Canonical<T> {
if ( !this.resources[key] ) {
throw new NoSuchCanonicalResolverKeyError(key)
}
return this.resources[key] as Canonical<T>
}
/**
* Get a canonical item from a fully-qualified canonical name.
* This is just a quality-of-life wrapper around `this.resource(...).get(...)`.
* @param key
*/
getFromFullyQualified(key: string): Maybe<any> {
const [namespace, ...parts] = key.split('::')
const unqualified = parts.join('::')
return this.resource(namespace).get(unqualified)
}
/**
* Register a canonical resource.
* @param {Canonical} unit
*/
registerCanonical(unit: Canonical<any>): void {
const key = unit.canonicalItems
if ( this.resources[key] ) {
throw new DuplicateResolverKeyError(key)
}
this.resources[key] = unit
}
}