index.js

function crossTab (config = {}) {
  let key = config.key || 'storeon-crosstab'

  let ignoreNext = false
  let ignoreDate = 0
  let counter = 0

  return function (store) {
    store.on('@dispatch', (_, [eventName, data]) => {
      if (eventName[0] === '@') {
        return
      }

      if (ignoreNext) {
        ignoreNext = false
        return
      }

      if (config.filter && !config.filter(eventName, data)) {
        return
      }

      try {
        ignoreDate = Date.now() + '' + counter++
        localStorage[key] = JSON.stringify([eventName, data, ignoreDate])
      } catch (e) {}
    })

    if (typeof window !== 'undefined') {
      window.addEventListener('storage', event => {
        if (event.key === key) {
          let [eventName, data, ignoreDateFromEvent] = JSON.parse(
            event.newValue
          )

          if (ignoreDate !== ignoreDateFromEvent) {
            ignoreNext = true
            store.dispatch(eventName, data)
          }
        }
      })
    }
  }
}

module.exports = { crossTab }