vuepress/lib/default-theme/util.js

export const hashRE = /#.*$/
export const extRE = /\.(md|html)$/
export const endingSlashRE = /\/$/
export const outboundRE = /^https?:/

export function normalize (path) {
  return path
    .replace(hashRE, '')
    .replace(extRE, '')
}

export function getHash (path) {
  const match = path.match(hashRE)
  if (match) {
    return match[0]
  }
}

export function ensureExt (path) {
  if (outboundRE.test(path)) {
    return path
  }
  const hashMatch = path.match(hashRE)
  const hash = hashMatch ? hashMatch[0] : ''
  const normalized = normalize(path)

  if (endingSlashRE.test(normalized)) {
    return path
  }
  return normalized + '.html' + hash
}

export function isActive (route, path) {
  const routeHash = route.hash
  const linkHash = getHash(path)
  if (linkHash && routeHash !== linkHash) {
    return false
  }
  const routePath = normalize(route.path)
  const pagePath = normalize(path)
  if (endingSlashRE.test(routePath) || endingSlashRE.test(pagePath)) {
    return routePath === pagePath
  } else {
    return routePath.indexOf(pagePath) === 0
  }
}

export function resolvePage (pages, rawPath, base) {
  if (base) {
    rawPath = resolvePath(rawPath, base)
  }
  const path = normalize(rawPath)
  for (let i = 0; i < pages.length; i++) {
    if (normalize(pages[i].path) === path) {
      return Object.assign({}, pages[i], {
        type: 'page',
        path: ensureExt(rawPath)
      })
    }
  }
  console.error(`[vuepress] No matching page found for sidebar item "${rawPath}"`)
  return {}
}

function resolvePath (relative, base, append) {
  const firstChar = relative.charAt(0)
  if (firstChar === '/') {
    return relative
  }

  if (firstChar === '?' || firstChar === '#') {
    return base + relative
  }

  const stack = base.split('/')

  // remove trailing segment if:
  // - not appending
  // - appending to trailing slash (last segment is empty)
  if (!append || !stack[stack.length - 1]) {
    stack.pop()
  }

  // resolve relative path
  const segments = relative.replace(/^\//, '').split('/')
  for (let i = 0; i < segments.length; i++) {
    const segment = segments[i]
    if (segment === '..') {
      stack.pop()
    } else if (segment !== '.') {
      stack.push(segment)
    }
  }

  // ensure leading slash
  if (stack[0] !== '') {
    stack.unshift('')
  }

  return stack.join('/')
}