RouterLink.ts

import {
  defineComponent,
  h,
  PropType,
  inject,
  computed,
  reactive,
  unref,
  VNodeProps,
  AllowedComponentProps,
  ComponentCustomProps,
  getCurrentInstance,
  watchEffect,
} from 'vue'
import { RouteLocationRaw, VueUseOptions, RouteLocation } from './types'
import { isSameRouteLocationParams, isSameRouteRecord } from './location'
import { routerKey, routeLocationKey } from './injectionSymbols'
import { RouteRecord } from './matcher/types'
import { NavigationFailure } from './errors'
import { isBrowser } from './utils'

export interface RouterLinkOptions {
  /**
   * Route Location the link should navigate to when clicked on.
   */
  to: RouteLocationRaw
  /**
   * Calls `router.replace` instead of `router.push`.
   */
  replace?: boolean
  // TODO: refactor using extra options allowed in router.push. Needs RFC
}

export interface RouterLinkProps extends RouterLinkOptions {
  /**
   * Whether RouterLink should not wrap its content in an `a` tag. Useful when
   * using `v-slot` to create a custom RouterLink
   */
  custom?: boolean
  /**
   * Class to apply when the link is active
   */
  activeClass?: string
  /**
   * Class to apply when the link is exact active
   */
  exactActiveClass?: string
  /**
   * Value passed to the attribute `aria-current` when the link is exact active. Defaults to "page"
   */
  ariaCurrentValue?:
    | 'page'
    | 'step'
    | 'location'
    | 'date'
    | 'time'
    | 'true'
    | 'false'
}

export type UseLinkOptions = VueUseOptions<RouterLinkOptions>

// TODO: we could allow currentRoute as a prop to expose `isActive` and
// `isExactActive` behavior should go through an RFC
export function useLink(props: UseLinkOptions) {
  const router = inject(routerKey)!
  const currentRoute = inject(routeLocationKey)!

  const route = computed(() => router.resolve(unref(props.to)))

  const activeRecordIndex = computed<number>(() => {
    let { matched } = route.value
    let { length } = matched
    const routeMatched: RouteRecord | undefined = matched[length - 1]
    let currentMatched = currentRoute.matched
    if (!routeMatched || !currentMatched.length) return -1
    let index = currentMatched.findIndex(
      isSameRouteRecord.bind(null, routeMatched)
    )
    if (index > -1) return index
    // possible parent record
    let parentRecordPath = getOriginalPath(
      matched[length - 2] as RouteRecord | undefined
    )
    return (
      // we are dealing with nested routes
      length > 1 &&
        // if the parent and matched route have the same path, this link is
        // referring to the empty child. Or we currently are on a different
        // child of the same parent
        getOriginalPath(routeMatched) === parentRecordPath &&
        // avoid comparing the child with its parent
        currentMatched[currentMatched.length - 1].path !== parentRecordPath
        ? currentMatched.findIndex(
            isSameRouteRecord.bind(null, matched[length - 2])
          )
        : index
    )
  })

  const isActive = computed<boolean>(
    () =>
      activeRecordIndex.value > -1 &&
      includesParams(currentRoute.params, route.value.params)
  )
  const isExactActive = computed<boolean>(
    () =>
      activeRecordIndex.value > -1 &&
      activeRecordIndex.value === currentRoute.matched.length - 1 &&
      isSameRouteLocationParams(currentRoute.params, route.value.params)
  )

  function navigate(
    e: MouseEvent = {} as MouseEvent
  ): Promise<void | NavigationFailure> {
    if (guardEvent(e))
      return router[unref(props.replace) ? 'replace' : 'push'](unref(props.to))
    return Promise.resolve()
  }

  return {
    route,
    href: computed(() => route.value.href),
    isActive,
    isExactActive,
    navigate,
  }
}

export const RouterLinkImpl = /*#__PURE__*/ defineComponent({
  name: 'RouterLink',
  props: {
    to: {
      type: [String, Object] as PropType<RouteLocationRaw>,
      required: true,
    },
    replace: Boolean,
    activeClass: String,
    // inactiveClass: String,
    exactActiveClass: String,
    custom: Boolean,
    ariaCurrentValue: {
      type: String as PropType<RouterLinkProps['ariaCurrentValue']>,
      default: 'page',
    },
  },

  setup(props, { slots }) {
    const link = reactive(useLink(props))
    const { options } = inject(routerKey)!

    const elClass = computed(() => ({
      [getLinkClass(
        props.activeClass,
        options.linkActiveClass,
        'router-link-active'
      )]: link.isActive,
      // [getLinkClass(
      //   props.inactiveClass,
      //   options.linkInactiveClass,
      //   'router-link-inactive'
      // )]: !link.isExactActive,
      [getLinkClass(
        props.exactActiveClass,
        options.linkExactActiveClass,
        'router-link-exact-active'
      )]: link.isExactActive,
    }))

    // devtools only
    if ((__DEV__ || __FEATURE_PROD_DEVTOOLS__) && isBrowser) {
      const instance = getCurrentInstance()
      watchEffect(
        () => {
          if (!instance) return
          ;(instance as any).__vrl_route = link.route
        },
        { flush: 'post' }
      )
      watchEffect(
        () => {
          if (!instance) return
          ;(instance as any).__vrl_active = link.isActive
          ;(instance as any).__vrl_exactActive = link.isExactActive
        },
        { flush: 'post' }
      )
    }

    return () => {
      const children = slots.default && slots.default(link)
      return props.custom
        ? children
        : h(
            'a',
            {
              'aria-current': link.isExactActive
                ? props.ariaCurrentValue
                : null,
              href: link.href,
              // this would override user added attrs but Vue will still add
              // the listener so we end up triggering both
              onClick: link.navigate,
              class: elClass.value,
            },
            children
          )
    }
  },
})

// export the public type for h/tsx inference
// also to avoid inline import() in generated d.ts files
/**
 * Component to render a link that triggers a navigation on click.
 */
export const RouterLink = RouterLinkImpl as {
  new (): {
    $props: AllowedComponentProps &
      ComponentCustomProps &
      VNodeProps &
      RouterLinkProps
  }
}

function guardEvent(e: MouseEvent) {
  // don't redirect with control keys
  if (e.metaKey || e.altKey || e.ctrlKey || e.shiftKey) return
  // don't redirect when preventDefault called
  if (e.defaultPrevented) return
  // don't redirect on right click
  if (e.button !== undefined && e.button !== 0) return
  // don't redirect if `target="_blank"`
  // @ts-expect-error getAttribute does exist
  if (e.currentTarget && e.currentTarget.getAttribute) {
    // @ts-expect-error getAttribute exists
    const target = e.currentTarget.getAttribute('target')
    if (/\b_blank\b/i.test(target)) return
  }
  // this may be a Weex event which doesn't have this method
  if (e.preventDefault) e.preventDefault()

  return true
}

function includesParams(
  outer: RouteLocation['params'],
  inner: RouteLocation['params']
): boolean {
  for (let key in inner) {
    let innerValue = inner[key]
    let outerValue = outer[key]
    if (typeof innerValue === 'string') {
      if (innerValue !== outerValue) return false
    } else {
      if (
        !Array.isArray(outerValue) ||
        outerValue.length !== innerValue.length ||
        innerValue.some((value, i) => value !== outerValue[i])
      )
        return false
    }
  }

  return true
}

/**
 * Get the original path value of a record by following its aliasOf
 * @param record
 */
function getOriginalPath(record: RouteRecord | undefined): string {
  return record ? (record.aliasOf ? record.aliasOf.path : record.path) : ''
}

/**
 * Utility class to get the active class based on defaults.
 * @param propClass
 * @param globalClass
 * @param defaultClass
 */
const getLinkClass = (
  propClass: string | undefined,
  globalClass: string | undefined,
  defaultClass: string
): string =>
  propClass != null
    ? propClass
    : globalClass != null
    ? globalClass
    : defaultClass