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74 lines
2.1 KiB
74 lines
2.1 KiB
import {Collection} from '../collection/Collection'
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import {uuid4} from './data'
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import {AsyncLocalStorage} from 'async_hooks'
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/**
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* Type structure for a single item in the global registry.
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*/
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export type GlobalRegistrant = { key: string | symbol, value: any }
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export class AccessGlobalRegistryOutsideAsyncLifecycleError extends Error {
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constructor() {
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super('Attempted to access global registry outside of an async context.')
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}
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}
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/**
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* A convenient class to manage global variables.
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*/
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export class GlobalRegistry {
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protected readonly storage: AsyncLocalStorage<Collection<GlobalRegistrant>> = new AsyncLocalStorage<Collection<GlobalRegistrant>>()
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/** Run a closure with a global registry. */
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public run<T>(closure: () => T): T {
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return this.storage.run(new Collection<GlobalRegistrant>(), (): T => {
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this.setGlobal('registry_uuid', uuid4())
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return closure()
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})
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}
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/**
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* Store the given `value` associated by `key`.
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* @param key
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* @param value
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*/
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public setGlobal(key: string | symbol, value: unknown): this {
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const existing = this.getCollection().firstWhere('key', '=', key)
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if ( existing ) {
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existing.value = value
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} else {
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this.getCollection().push({
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key,
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value,
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})
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}
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return this
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}
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/**
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* Retrieve the value of the given `key`, if it exists in the store.
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* @param key
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*/
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public getGlobal(key: string | symbol): any {
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return this.getCollection().firstWhere('key', '=', key)?.value
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}
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/** Get the globals collection or throw an error if outside async context. */
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protected getCollection(): Collection<GlobalRegistrant> {
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const coll = this.storage.getStore()
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if ( !coll ) {
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throw new AccessGlobalRegistryOutsideAsyncLifecycleError()
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}
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return coll
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}
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}
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/**
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* Export a singleton global registry for all code to share.
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*
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* Exporting an instance here guarantees that all code that import it will get the same instance.
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*/
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export const globalRegistry = new GlobalRegistry()
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