operator

1.8kb drop-in "PJAX" solution for fluid, smooth transitions between pages. Zero stress.

Features

Advanced routing via matchit
Client-side redirects
Async-by-default, easy data loading between routes
Pages are cached after initial visit
Pre-fetch select pages, as needed

Install

npm i operator --save

Usage

Basically zero config by default, just specify a root DOM node to attach to.

import operator from 'operator'

operator('#root')

Defining routes

To define custom handlers for a given route, pass an object with a path property and handler method.

operator('#root', [
  {
    path: '/',
    handler (state) {
      console.log(state)
    }
  }
])

Routes handlers can also return Promises, and they support params, optional params, and wildcards.

operator('#root', [
  {
    path: '/',
    handler (state) {
      console.log(state)
    }
  },
  {
    path: '/products',
    handler (state) {
      return getProducts() // Promise
    }
  },
  {
    path: '/products/:category/:slug?',
    handler ({ params }) {
      const reqs = [ getProductCategory(params.category) ]
      if (params.slug) reqs.push(getProductBySlug(params.slug))
      return Promise.all(reqs)
    }
  }
])

Route Caching

Routes are cached by default, so on subsequent visits, no data will be loaded. To follow links to pages via AJAX, but fetch fresh content on each navigation action, set cache to false:

operator('#root', [
  {
    'path': '/',
    cache: false
  }
])

Ignoring Routes

Sometimes you need to navigate to a page without AJAX, perhaps to load some sort of iframe content. To do so, set ignore to true:

operator('#root', [
  {
    'path': '/',
    ignore: true
  }
])

Lifecycle

Any function passed to the route config will be called on every route change, kind of like middleware.

const app = operator('#root', [
  state => console.log(state)
])

Operator also emits some helpful events.

app.on('navigate', state => {}) // on valid link click
app.on('before', state => {}) // before render
app.on('after', state => {}) // after render
app.on('hash', state => {}) // when the URL contains a hash

History state

Operator does not manage History or page title, for maximum flexibility to the user. Most people should probably just use this snippet:

app.on('after', ({ previousDocument, location }) => {
  document.title = previousDocumnt.title
  window.history.pushState({}, '', location)
})

If you want to ignore things like query strings or hashes, use pathname:

app.on('after', ({ previousDocumnt, pathname }) => {
  document.title = previousDocumnt.title
  window.history.pushState({}, '', pathname)
})

Hash Anchors

When a hash is encountered – whether on a navigate action between pages, or for scroll-anchors on the same page - Operator will emit a hash event. It's up to you to handle scrolling.

For most sites, this should work:

app.on('hash', ({ hash }) => {
  const target = document.getElementById(hash)

  if (target) {
    const scroll = target.getBoundingClientRect().top + window.pageYOffset
    window.scrollTo(0, scroll)
  }
})

Smooth scrolling is also pretty easy:

import sscroll from 'sscroll'

app.on('hash', ({ hash }) => {
  const target = document.getElementById(hash)
  target && sscroll(target, { duration: 500 })
})

API

go(path)

app.go('/about')

load(path)

Use this for prefetching pages.

app.load('/about')

state (getter)

app.state // => { previousDocument, pathname, location, params, hash, search, handler }

Recipes

Redirects

app.on('before', ({ pathname }) => {
  if (/redirect/.test(pathname)) {
    app.go('/') // redirect
  }
})

Transition animation

import wait from 'w2t'

operator('#root', [
  state => {
    return wait(600, [
      const root = document.documentElement.classList
      return new Promise(res => {
        root.add('is-transitioning')
        setTimeout(() => {
          root.remove('is-transitioning')
          res()
        }, 600)
      })
    ])
  }
])

Changelog

v1.8.0

Removed default scroll handling. This should be moved to user-space in the event the user doesn't want the page to reset to the top.

v1.7.0

Added previousDocument (a complete cloned document object) to the state object. Replaces state.title via previousDocument.title.

v1.6.0

Implemented hash event, see docs
Fix bad mailto and tel regex, thanks @gabrielloeb!

v1.2.0

Slight update to the API, will require brief migration to new syntax for most users.

Deprecated Array format for route configs in favor of more flexible Object syntax
Add ignore and cache options

mikehwagz/operator