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HistoryStateStore.js
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HistoryStateStore.js
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// special store, state is href string
const createHistoryStateStore = (state = window.location.href) => {
const getState = () => {
if (listenerSet.size === 0) throw new Error('should subscribe before getState')
return state
}
const setState = (nextState, shouldPushState) => {
if (typeof (nextState) !== 'string') throw new Error(`non-string href: ${nextState}`)
if (nextState === state) return state
const prevState = state
state = nextState
shouldPushState !== 'skip' && window.history.pushState(null, '', state)
listenerSet.forEach((listener) => listener(state, prevState))
return state
}
const listenerPopState = () => { setState(window.location.href, 'skip') }
const listenerHashChange = () => { setState(window.location.href) }
const listenerSet = new Set()
const subscribe = (listener) => {
listenerSet.add(listener)
if (listenerSet.size !== 1) return
window.addEventListener('popstate', listenerPopState)
window.addEventListener('hashchange', listenerHashChange)
}
const unsubscribe = (listener) => {
listenerSet.delete(listener)
if (listenerSet.size !== 0) return
window.removeEventListener('popstate', listenerPopState)
window.removeEventListener('hashchange', listenerHashChange)
}
return { getState, setState, subscribe, unsubscribe }
}
export { createHistoryStateStore }