v5.0.21

Omi - Next generation web framework using web components with omio fallback(IE8+) in tiny js.

Why Omi?

Tiny size
Supports TypeScript
Reactive data-binding
Having official UI components - omiu
Excellent compatibility(IE8+) with omio
Real MVVM with mappingjs strong support
Enhanced CSS, rpx unit support base on 750 screen width
Compliance with browser trend and API design
Merge Web Components and JSX into one framework
Web Components can also be a data-driven view, UI = fn(data).
JSX is the best development experience (code intelligent completion and tip) UI Expression with least grammatical noise and it's turing complete(template engine is not, es template string is but grammatical noise is too loud)
Look at Facebook React vs Web Components，Omi combines their advantages and gives developers the freedom to choose the way they like
Shadow DOM merges with Virtual DOM, Omi uses both virtual DOM and real Shadow DOM to make view updates more accurate and faster
Scoped CSS's best solution is Shadow DOM, the community churning out frameworks and libraries for Scoped CSS (using JS or JSON writing styles such as Radium, jsxstyle, react-style; binding to webpack using generated unique className filename-classname-hash, such as CSS Modules, Vue), are hack technologies; and Shadow DOM Style is the perfect solution.

Compare TodoApp by Omi and React, Omi and React rendering DOM structure:

Omi	React

Omi uses Shadow DOM based style isolation and semantic structure.

Ecosystem of Omi

Project	Description
omi-docs	Omi official documents
omio	Omi for old browsers(IE8+ and mobile browsers).
omiu	Omi official UI
omi-chart	Simple HTML5 Charts using chart-x tag.
md2site	Static Site Generator with markdown powered by Omio.
omi-mvvm	MVVM comes back bravely with mappingjs strong support.
omi-html	Using htm in omi.
omi-30-seconds	Useful Omi snippets that you can understand in 30 seconds.
omi-canvas	Perfect fusion of web components, jsx and canvas.
omi-mp	Develop and generate Web HTML5 Single-Page Applications by wechat mini program. The output source is base on omi + omi-router
omi-router	Omi official router in 1KB js. → DEMO
omi-devtools	Browser DevTools extension
omi-cli	Project scaffolding
omi-ex	Omi.js extension(TypeScript)
omi-transform	Omi / css3transform integration. Made css3 transform super easy in your Omi project.
omi-tap	Native tap event support(omi v4.0.24+）
omi-finger	Support touch and gesture events in your Omi project.
omi-touch	Smooth scrolling, rotation, pull to refresh and any motion for the web.
omi-use	React hooks like API
omi-native	Render web components to native
omi-i18n	Internationalization solution for omi.js using i18next ecosystem
omi-page	Tiny client-side router by page

Useful Resources

Title Name	Other language	Related
Styling We Components Using A Shared Style Sheet
Developer Tools support for Web Components in Firefox 63
Develop W3C Web Components with WebAssembly
60FPS Animation In Omi	简体中文 한국어
Render Web Components To Native	简体中文 한국어
Shadow Dom In Depth	简体中文
Part Theme Explainer	求翻译
Web Components MDN	简体中文
Web Components Google
Web Components Org
Web Components: the Right Way
Proxy MDN	简体中文 한국어
CSS Variables	简体中文 한국어
CSS Shadow Parts
Platform HTML5
Using requestIdleCallback	简体中文	A polyfill
The Power Of Web Components	简体中文
ShadowRoot	简体中文

Overview of the Readme

Ecosystem of Omi
Useful Resources
Add Omi in One Minute
Add Omi in 30 Seconds
Getting Started
- Install
- Project Template
- Hello Element
- TodoApp
- Store
- Mitt
- Observe
- Lifecycle
Debugging
React to Omi
Browsers Support
Contributors
Maintainers
Thanks
License

Add Omi in One Minute

This page demonstrates using Omi with no build tooling.

<!DOCTYPE html>
<html>

<head>
  <meta charset="UTF-8" />
  <title>Add Omi in One Minute</title>
</head>

<body>
  <script src="https://unpkg.com/omi"></script>
  <script>
    const { WeElement, h, render, define } = Omi

    define('like-button', class extends WeElement {
        install() {
          this.data = { liked: false }
        }

        render() {
          if (this.data.liked) {
            return 'You liked this.'
          }

          return h(
            'button',
            {
              onClick: () => {
                this.data.liked = true
                this.update()
              }
            },
            'Like'
          )
        }
      })

    render(h('like-button'), 'body')
  </script>
</body>

</html>

You can also use like-button tag directly in HTML：

<body>
  <like-button />
</body>

Add Omi in 30 Seconds

You can also quickly build omi projects using modern JS code:

import { render, WeElement, define } from 'omi'

define('my-counter', class extends WeElement {
    static observe = true
    
    data = {
      count: 1
    }

    css () {
      return `span{
        color: red;
      }`
    }

    sub = () => {
      this.data.count--
    }

    add = () => {
      this.data.count++
    }

    render() {
      return (
        <div>
          <button onClick={this.sub}>-</button>
          <span>{this.data.count}</span>
          <button onClick={this.add}>+</button>
        </div>
      )
    }
  })

render(<my-counter />, 'body')

You can also update the view manually then you can choose the best time to update.

import { render, WeElement, define } from 'omi'

define('my-counter', class extends WeElement {
  count = 1

  //You can also pass strings directly
  css = `span{
        color: red;
      }`

  sub = () => {
    this.count--
    this.update()
  }

  add = () => {
    this.count++
    this.update()
  }

  render() {
    return (
      <div>
        <button onClick={this.sub}>-</button>
        <span>{this.count}</span>
        <button onClick={this.add}>+</button>
      </div>
    )
  }
})

render(<my-counter />, 'body')

→ counter demo

Getting Started

Install

$ npm i omi-cli -g               # install cli
$ omi init my-app     # init project, you can also exec 'omi init' in an empty folder
$ cd my-app           # please ignore this command if you executed 'omi init' in an empty folder
$ npm start                      # develop
$ npm run build                  # release

npx omi-cli init my-app is also supported(npm v5.2.0+).

Directory description:

├─ config
├─ public
├─ scripts
├─ src
│  ├─ assets
│  ├─ elements    //Store all custom elements
│  ├─ store       //Store all this store of pages
│  ├─ admin.js    //Entry js of compiler，will build to admin.html
│  └─ index.js    //Entry js of compiler，will build to index.html

Scripts

"scripts": {
    "start": "node scripts/start.js",
    "build": "PUBLIC_URL=. node scripts/build.js",
    "build-windows": "set PUBLIC_URL=.&& node scripts/build.js",
    "fix": "eslint src --fix"
}

You can set up the PUBLIC_URL, such as：

...
"build": "PUBLIC_URL=https://fe.wxpay.oa.com/dv node scripts/build.js",
"build-windows": "set PUBLIC_URL=https://fe.wxpay.oa.com/dv&& node scripts/build.js",
...

Switch omi and omio

Add or remove the alias config in package.json to switch omi and omio：

 ...
 "alias": {
    "omi": "omio"
  }
  ...

Project Template

Template Type	Command	Describe
Base Template(v3.3.0+)	`omi init my-app`	Basic omi or omio(IE8+) project template.
Base Template with snapshoot	`omi init-snap my-app`	Basic omi or omio(IE8+) project template with snapshoot prerendering.
TypeScript Template(omi-cli v3.3.0+)	`omi init-ts my-app`	Basic template with typescript.
Mobile Template	`omi init-weui my-app`	Mobile web app template with weui and omi-router.
SPA Template(omi-cli v3.0.10+)	`omi init-spa my-app`	Single page application template with omi-router.
omi-mp Template(omi-cli v3.0.13+)	`omi init-mp my-app`	Developing web with mini program template.
MVVM Template(omi-cli v3.0.22+)	`omi init-mvvm my-app`	MVVM template.

CLI's auto-created project scaffolding is based on a single-page create-react-app to be converted into a multi-page one, with configuration issues to see create-react-app user guide

Hello Element

Define a custom element by extending WeElement base class:

import { define, WeElement } from 'omi'

define('hello-element', class extends WeElement {
  onClick = evt => {
    // trigger CustomEvent
    this.fire('abc', { name: 'dntzhang', age: 12 })
    evt.stopPropagation()
  }

 css = `
      div {
        color: red;
        cursor: pointer;
      }`
  }

  render(props) {
    return (
      <div onClick={this.onClick}>
        Hello {props.msg} {props.propFromParent}
        <div>Click Me!</div>
      </div>
    )
  }
})

Using hello-element:

import { define, render, WeElement } from 'omi'
import './hello-element'

define('my-app', class extends WeElement {
  data = { abc: 'abc', passToChild: 123 }

  // define CustomEvent Handler
  onAbc = evt => {
    // get evt data by evt.detail
    this.data.abc = ' by ' + evt.detail.name
    this.data.passToChild = 1234
    this.update()
  }

  css = `
      div{
          color: green;
      }`
  }

  render(props, data) {
    return (
      <div>
        Hello {props.name} {data.abc}
        <hello-element
          onAbc={this.onAbc}
          propFromParent={data.passToChild}
          msg="WeElement"
        />
      </div>
    )
  }
})

render(<my-app name="Omi v4.0" />, 'body')

Tell Babel to transform JSX into Omi.h() call:

{
  "presets": ["env", "omi"]
}

The following two NPM packages need to be installed to support the above configuration:

"babel-preset-env": "^1.6.0",
"babel-preset-omi": "^0.1.1",

If you use babel7, you can also use the following packages and configuration:

npm install --save-dev @babel/preset-env
npm install --save-dev @babel/preset-react

{
  "presets": [
    "@babel/preset-env",
    [
      "@babel/preset-react",
      {
        "pragma": "Omi.h"
      }
    ]
  ]
}

If you don't want to write CSS in JS, you can use to-string-loader of webpack, For example, the following configuration:

{
  test: /[\\|\/]_[\S]*\.css$/,
  use: [
    'to-string-loader',
    'css-loader'
  ]
}

If your CSS file starts with "_", CSS will use to-string-loader., such as:

import { tag, WeElement render } from 'omi'

define('my-app', class extends WeElement {

  css = require('./_index.css')
  ...
  ...
  ...

You can also forget the tedious configuration and use omi-cli directly, no need to configure anything.

TodoApp

Here is a relatively complete example of TodoApp:

import { define, render, WeElement } from 'omi'

define('todo-list', function(props) {
  return (
    <ul>
      {props.items.map(item => (
        <li key={item.id}>{item.text}</li>
      ))}
    </ul>
  )
})

define('todo-app', class extends WeElement {
  static observe = true

  data = { items: [], text: '' }

  render() {
    return (
      <div>
        <h3>TODO</h3>
        <todo-list items={this.data.items} />
        <form onSubmit={this.handleSubmit}>
          <input
            id="new-todo"
            onChange={this.handleChange}
            value={this.data.text}
          />
          <button>Add #{this.data.items.length + 1}</button>
        </form>
      </div>
    )
  }

  handleChange = e => {
    this.data.text = e.target.value
  }

  handleSubmit = e => {
    e.preventDefault()
    if (!this.data.text.trim().length) {
      return
    }
    this.data.items.push({
      text: this.data.text,
      id: Date.now()
    })
    this.data.text = ''
  }
})

render(<todo-app />, 'body')

Store

Omi Store provides a way to pass data through the component tree without having to pass props down manually at every level, injected from the root component and shared across all subcomponents. It's very simple to use:

import { define, render, WeElement } from 'omi'

define('my-hello', class extends WeElement {
  render() {
    //use this.store in any method of any children components
    return <div>{this.store.name}</div>
  }
})

define('my-app', class extends WeElement {
  handleClick = () => {
     //use this.store in any method of any children components
    this.store.reverse()
    this.update()
  }

  render() {
    return (
      <div>
        <my-hello />
        <button onclick={this.handleClick}>reverse</button>
      </div>
    )
  }
})

const store = {
  name: 'abc',
  reverse: function() {
    this.name = this.name.split("").reverse().join("")
  }
}
//Injection through a third parameter
render(<my-app />, document.body, store)

Unlike global variables, when there are multiple root nodes, multiple stores can be injected, while there is only one global variable.

Mitt

If you don't want to use store's data system, you can also use publish subscribe mode. For example, using mitt across component communication in Omi:

cross-component-communication

Observe

Omi Observe

You can also use observe to create response views for element who no need store, such as:

import { define, WeElement } from "omi"

define("my-app", class extends WeElement {
  static observe = true

  install() {
    this.data.name = "omi"
  }

  onClick = () => {
    this.data.name = "Omi V4.0"
  }

  render(props, data) {
    return (
      <div onClick={this.onClick}>
        <h1>Welcome to {data.name}</h1>
      </div>
    )
  }
})

Lifecycle

Lifecycle method	When it gets called
`install`	before the component gets mounted to the DOM
`installed`	after the component gets mounted to the DOM
`uninstall`	prior to removal from the DOM
`beforeUpdate`	before update
`updated`	after update
`beforeRender`	before `render()`
`receiveProps`	parent element re-render will trigger it

Debugging

Easy to debug via Omi DevTools Extension [Install from Chrome WebStore], using Omi DevTools you can simply debug and manage your UI without any configuration. Just install and debug.

Since Omi uses Web Components and Shadow-DOM, it doesn't need to have another elements panel such as React has. It just adds a panel to the Elements' sidebar and it's powerful as much as React DevTools.

React to Omi

For example, the below is about migration React button as weui Omi button:

Browsers Support

Omio - Omi for old browsers(IE8+ and mobile browsers)

Omi 4.0+ works in the latest two versions of all major browsers: Safari 10+, IE 11+, and the evergreen Chrome, Firefox, and Edge.

→ Polyfills

<script src="https://unpkg.com/@webcomponents/webcomponentsjs@2.0.0/webcomponents-bundle.js"></script>

Contributors

Maintainers

Please contact us for any questions. Also, Add Omi QQ Group.

flyfly6/omi