56 lines
1.5 KiB
TypeScript
56 lines
1.5 KiB
TypeScript
import { produce } from "immer"
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type Listener<State> = (state: State) => void
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type SetStateAction<State> = (state: State) => void
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export const FETCH_STATES = ["idle", "loading", "error", "success"] as const
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export type FetchState = (typeof FETCH_STATES)[number]
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export type ErrorGlobal = "unknown" | null
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export abstract class Presenter<State> {
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private _state: State
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private readonly _initialState: State
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private readonly _listeners: Array<Listener<State>>
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public constructor(initialState: State) {
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this._state = initialState
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this._initialState = initialState
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this._listeners = []
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}
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public get initialState(): State {
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return this._initialState
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}
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/**
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* @description Set the state of the presenter.
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* @param action A function that receives the current state and can update it by mutating it.
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* @returns The new state.
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*/
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public setState(action: SetStateAction<State>): State {
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this._state = produce(this._state, action)
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this.notifyListeners()
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return this._state
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}
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public subscribe(listener: Listener<State>): void {
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this._listeners.push(listener)
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}
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public unsubscribe(listener: Listener<State>): void {
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const listenerIndex = this._listeners.indexOf(listener)
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const listenerFound = listenerIndex !== -1
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if (listenerFound) {
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this._listeners.splice(listenerIndex, 1)
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}
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}
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private notifyListeners(): void {
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for (const listener of this._listeners) {
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listener(this._state)
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}
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}
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}
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