hash.js

/* @flow */

import type Router from '../index'
import { History } from './base'
import { cleanPath } from '../util/path'
import { getLocation } from './html5'
import { setupScroll, handleScroll } from '../util/scroll'
import { pushState, replaceState, supportsPushState } from '../util/push-state'

export class HashHistory extends History {
  constructor (router: Router, base: ?string, fallback: boolean) {
    super(router, base)
    // check history fallback deeplinking
    if (fallback && checkFallback(this.base)) {
      return
    }
    ensureSlash()
  }

  // this is delayed until the app mounts
  // to avoid the hashchange listener being fired too early
  setupListeners () {
    const router = this.router
    const expectScroll = router.options.scrollBehavior
    const supportsScroll = supportsPushState && expectScroll

    if (supportsScroll) {
      setupScroll()
    }

    window.addEventListener(
      supportsPushState ? 'popstate' : 'hashchange',
      () => {
        const current = this.current
        if (!ensureSlash()) {
          return
        }
        this.transitionTo(getHash(), route => {
          if (supportsScroll) {
            handleScroll(this.router, route, current, true)
          }
          if (!supportsPushState) {
            replaceHash(route.fullPath)
          }
        })
      }
    )
  }

  push (location: RawLocation, onComplete?: Function, onAbort?: Function) {
    const { current: fromRoute } = this
    this.transitionTo(
      location,
      route => {
        pushHash(route.fullPath)
        handleScroll(this.router, route, fromRoute, false)
        onComplete && onComplete(route)
      },
      onAbort
    )
  }

  replace (location: RawLocation, onComplete?: Function, onAbort?: Function) {
    const { current: fromRoute } = this
    this.transitionTo(
      location,
      route => {
        replaceHash(route.fullPath)
        handleScroll(this.router, route, fromRoute, false)
        onComplete && onComplete(route)
      },
      onAbort
    )
  }

  go (n: number) {
    window.history.go(n)
  }

  ensureURL (push?: boolean) {
    const current = this.current.fullPath
    if (getHash() !== current) {
      push ? pushHash(current) : replaceHash(current)
    }
  }

  getCurrentLocation () {
    return getHash()
  }
}

function checkFallback (base) {
  const location = getLocation(base)
  if (!/^\/#/.test(location)) {
    window.location.replace(cleanPath(base + '/#' + location))
    return true
  }
}

function ensureSlash (): boolean {
  const path = getHash()
  if (path.charAt(0) === '/') {
    return true
  }
  replaceHash('/' + path)
  return false
}

export function getHash (): string {
  // We need to get the raw hash to keep consistent behavior with routes
  // `fullPath` using encoded path. The params are decoded later in the
  // matcher.
  let href = window.location.href
  const index = href.indexOf('#')
  // empty path
  if (index < 0) return ''

  href = href.slice(index + 1)
  return href
}

function getUrl (path) {
  const href = window.location.href
  const i = href.indexOf('#')
  const base = i >= 0 ? href.slice(0, i) : href
  return `${base}#${path}`
}

function pushHash (path) {
  if (supportsPushState) {
    pushState(getUrl(path))
  } else {
    window.location.hash = path
  }
}

function replaceHash (path) {
  if (supportsPushState) {
    replaceState(getUrl(path))
  } else {
    window.location.replace(getUrl(path))
  }
}