kopia lustrzana https://github.com/Tldraw/Tldraw
101 wiersze
2.8 KiB
TypeScript
101 wiersze
2.8 KiB
TypeScript
import { BaseSession } from './sessions'
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/**
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* # Session Manager
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*
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* Sessions are instances that manage data mutations for activities such as
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* dragging, transforming, drawing, etc. The session manager singleton provides
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* an API with which the state's actions can begin a session and interact it.
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*
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* A session has a lifecycle:
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*
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* - it `begin`s when the session instance is created
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* - it receives `update`s during the session
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* - it ends either when it is `complete`d or `cancel`led
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*
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* Each session may produce different effects during these life cycles, according
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* to its implementation. Most sessions call a command when completed.
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*
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* It's intended that only a single session occurs at once. This pattern helps
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* ensure that we don't accidentally begin a new session before the current one
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* is cancelled or completes.
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*/
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class SessionManager {
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#current?: BaseSession
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/**
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* Begin a new session.
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* @param session A Session instance.
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* @example
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* ```ts
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* session.begin(new Sessions.EditSession(data))
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* ```
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*/
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begin(session: BaseSession) {
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if (this.#current) {
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throw Error(
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'Cannot begin a session until the current session is complete. This error indicates a problem with the state chart.'
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)
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}
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this.#current = session
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return this
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}
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/**
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* Update the current session. Include the session type as a generic in order to properly type the arguments.
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* @param args The arguments of the current session's `update` method.
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* @example
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* ```ts
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* session.update<Sessions.EditSession>(data, payload.change)
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* ```
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*/
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update<T extends BaseSession>(...args: Parameters<T['update']>) {
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const session = this.#current
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if (session === undefined) {
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throw Error('No current session.')
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}
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session.update.call(this.#current, ...args)
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return this
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}
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/**
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* Complete the current session. Include the session type as a generic in order to properly type the arguments.
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* @param args The arguments of the current session's `complete` method.
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* @example
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* ```ts
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* session.update<Sessions.EditSession>(data, payload.change)
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* ```
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*/
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complete<T extends BaseSession>(...args: Parameters<T['complete']>) {
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this.#current?.complete.call(this.#current, ...args)
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this.#current = undefined
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return this
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}
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/**
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* Cancel the current session.
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* @param args The arguments of the current session's `cancel` method.
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* @example
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* ```ts
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* session.cancel(data)
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* ```
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*/
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cancel<T extends BaseSession>(...args: Parameters<T['cancel']>) {
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this.#current?.cancel.call(this.#current, ...args)
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this.#current = undefined
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return this
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}
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get isInSession() {
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return this.#current !== undefined
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}
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}
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const session = new SessionManager()
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export default session
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