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import { isSSR } from './core.ts'
export class Store<S = any> {  private _state: S  private _prevState: S  private _listeners: Map<string, Function> = new Map()  private _storage: 'memory' | 'local' | 'session'  private _id: string
  /**   * Create your own Store.   * @param defaultState Pass the initial State.   * @param name The name of the Store (only required if you persist the state in localStorage or sessionStorage).   * @param storage Pass 'memory', 'local' or 'session'.   */  constructor(defaultState: Object, name: string = '', storage: 'memory' | 'local' | 'session' = 'memory') {    if (isSSR()) storage = 'memory'
    this._id = name    this._storage = storage
    this._state = this._prevState = defaultState as any
    if (storage === 'memory' || !storage) return
    const Storage = storage === 'local' ? localStorage : sessionStorage
    // get/set initial state of Storage    const item = Storage.getItem(this._id)    if (item) {      this._state = this._prevState = JSON.parse(item)    } else Storage.setItem(this._id, JSON.stringify(defaultState))  }
  private persist(newState: S) {    if (this._storage === 'memory') return    const Storage = this._storage === 'local' ? localStorage : sessionStorage    Storage.setItem(this._id, JSON.stringify(newState))  }
  /** Clears the state of the whole store. */  public clear() {    // @ts-ignore    this._state = this._prevState = undefined
    if (this._storage === 'local') localStorage.removeItem(this._id)    else if (this._storage === 'session') sessionStorage.removeItem(this._id)  }
  public setState(newState: S) {    this.state = newState  }
  public set state(newState: S) {    this._prevState = this._state    this._state = newState
    this.persist(newState)
    this._listeners.forEach(fnc => {      fnc(this._state, this._prevState)    })  }
  public get state(): S {    return this._state  }
  public use() {    const id = Math.random().toString(36).substring(2, 9)    const _this = this    return {      get state(): S {        return _this.state      },      setState: (newState: S) => {        this.state = newState      },      subscribe: (fnc: (newState: S, prevState: S) => void) => {        this._listeners.set(id, fnc)      },      cancel: () => {        if (this._listeners.has(id)) this._listeners.delete(id)      }    }  }}