metamask-extension/app/scripts/controllers/alert.js

import ObservableStore from 'obs-store'

/**
 * @typedef {Object} AlertControllerInitState
 * @property {Object} alertEnabledness - A map of alerts IDs to booleans, where
 * `true` indicates that the alert is enabled and shown, and `false` the opposite.
 * @property {Object} unconnectedAccountAlertShownOrigins - A map of origin
 * strings to booleans indicating whether the "switch to connected" alert has
 * been shown (`true`) or otherwise (`false`).
 */

/**
 * @typedef {Object} AlertControllerOptions
 * @property {AlertControllerInitState} initState - The initial controller state
 */

export const ALERT_TYPES = {
  unconnectedAccount: 'unconnectedAccount',
  // enumerated here but has no background state
  invalidCustomNetwork: 'invalidCustomNetwork',
}

const defaultState = {
  alertEnabledness: Object.keys(ALERT_TYPES)
    .reduce(
      (alertEnabledness, alertType) => {
        alertEnabledness[alertType] = true
        return alertEnabledness
      },
      {},
    ),
  unconnectedAccountAlertShownOrigins: {},
}

/**
 * Controller responsible for maintaining
 * alert related state
 */
export default class AlertController {

  /**
   * @constructor
   * @param {AlertControllerOptions} [opts] - Controller configuration parameters
   */
  constructor (opts = {}) {
    const { initState, preferencesStore } = opts
    const state = {
      ...defaultState,
      ...initState,
      unconnectedAccountAlertShownOrigins: {},
    }

    this.store = new ObservableStore(state)

    this.selectedAddress = preferencesStore.getState().selectedAddress

    preferencesStore.subscribe(({ selectedAddress }) => {
      const currentState = this.store.getState()
      if (currentState.unconnectedAccountAlertShownOrigins && this.selectedAddress !== selectedAddress) {
        this.selectedAddress = selectedAddress
        this.store.updateState({ unconnectedAccountAlertShownOrigins: {} })
      }
    })
  }

  setAlertEnabledness (alertId, enabledness) {
    let { alertEnabledness } = this.store.getState()
    alertEnabledness = { ...alertEnabledness }
    alertEnabledness[alertId] = enabledness
    this.store.updateState({ alertEnabledness })
  }

  /**
   * Sets the "switch to connected" alert as shown for the given origin
   * @param {string} origin - The origin the alert has been shown for
   */
  setUnconnectedAccountAlertShown (origin) {
    let { unconnectedAccountAlertShownOrigins } = this.store.getState()
    unconnectedAccountAlertShownOrigins = { ...unconnectedAccountAlertShownOrigins }
    unconnectedAccountAlertShownOrigins[origin] = true
    this.store.updateState({ unconnectedAccountAlertShownOrigins })
  }
}