stonex

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import { StonexModule } from '.'
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import { copy, isType, noop, types } from './helpers/base'
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declare interface EmptyStateMap {
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  [moduleName: string]: any
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}
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/**
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 * StateWorker it is class which do all work
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 * linked with state inside each Stonex Module connected to the store
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 *
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 * @export
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 * @class StateWorker
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 * @template StateMap
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 *
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 *
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 * @example
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 * import { StateWorker, StonexStore } from '../src'
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 * import modules, { Modules } from './modules'
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 *
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 * class SuperStateWorker extends StateWorker {
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 *
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 *  getState(moduleName: string){
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 *    // own behaviour
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 *    return super.getState(moduleName)
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 *  }
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 * }
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 *
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 * const store = new StonexStore<Modules>(modules,{
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 *  stateWorker: SuperStateWorker
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 * })
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 */
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export class StateWorker<StateMap = EmptyStateMap> {
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  /**
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   * Map of stonex module states
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   *
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   * @public
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   * @type {StateMap}
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   * @memberof StateWorker
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   */
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  public state: StateMap = {} as StateMap
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  /**
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   * Method which calls when Stonex initializing state inside your module
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   *
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   * @param {StonexModule<State>} moduleInstance
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   *
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   * @public
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   */
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  public initializeState<State = any> (moduleInstance: StonexModule<State>): void {
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    this.state[moduleInstance.moduleName] = copy(moduleInstance.__initialState)
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    Object.defineProperty(moduleInstance, 'state', {
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      get: () => moduleInstance.getState(),
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      set: () => {
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        throw new Error(
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          `State of the module ${moduleInstance.moduleName} is immutable.\r\n` +
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          `Please use "this.setState" for updating state of the ${moduleInstance.moduleName} module`
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        )
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      },
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    })
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  }
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  /**
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   * Preparing new state to update
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   *
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   * @param {StonexModule<State>} moduleInstance
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   * @param {Partial<State> | ((state: State) => Partial<State>)} changes
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   * @param {function?} callback
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   *
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   * @public
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   */
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  public setState<State> (
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    moduleInstance: StonexModule<State>,
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    changes: Partial<State> | ((state: State) => Partial<State>),
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    callback: (state: State) => any = noop
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  ): void {
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    const changesAsFunction = isType(changes, types.function)
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    const changeAction = (stateChanges: Partial<State>) => {
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      this.updateState<State>(moduleInstance, stateChanges)
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      callback(moduleInstance.state)
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    }
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    if (changesAsFunction) {
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      setTimeout(() => changeAction((changes as (state: State) => Partial<State>)(moduleInstance.state)), 0)
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    } else {
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      changeAction(changes as Partial<State>)
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    }
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  }
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  /**
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   * Returns state of stonex module
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   *
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   * @param {string} moduleName
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   *
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   * @public
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   */
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  public getState<State> (moduleName: string): State {
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    return copy(this.state[moduleName])
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  }
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  /**
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   * Reset state of stonex module
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   *
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   * @param {StonexModule<State>} moduleInstance
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   * @param {function?} callback
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   *
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   * @public
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   */
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  public resetState<State> (moduleInstance: StonexModule<State>, callback: (state: any) => any = noop): void {
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    return this.setState(moduleInstance, moduleInstance.__initialState, callback)
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  }
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  /**
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   * Updating state of stonex module
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   *
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   * @param {StonexModule<State>} moduleInstance
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   * @param {Partial<State>} stateChanges
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   */
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  private updateState<State> (moduleInstance: StonexModule<State>, stateChanges: Partial<State>): void | never {
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    let flattedStateChanges = null
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    if (isType(stateChanges, types.function)) {
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      throw new Error(`State of ${moduleInstance.moduleName} module can not have the type of function`)
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    }
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    if (isType(stateChanges, types.object)) {
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      flattedStateChanges = { ...copy(stateChanges) }
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    } else {
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      flattedStateChanges = isType(stateChanges, types.array) ? [...copy(stateChanges)] : stateChanges
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    }
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    this.state[moduleInstance.moduleName] = flattedStateChanges
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  }
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}
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