MobX JSX

This library is a demonstration of how MobX fine grain control can be leveraged directly in JSX for considerably better performance than pairing it with a Virtual DOM library. Even the fastest Virtual DOM library will have overhead when reconciling many small discrete changes into a scheduled render and patch.

Check out MobX JSX performance near the top of the charts on the JS Frameworks Benchmark.

It accomplishes this with using Babel Plugin JSX DOM Expressions. It compiles JSX to DOM statements and wraps expressions in functions that can be called by the library of choice. In this case

autorun

Usage

To use call render as follow

import { render } from "mobx-jsx";

render(App, document.getElementById("main"));

And include 'babel-plugin-jsx-dom-expressions' in your babelrc, webpack babel loader, or rollup babel plugin.

"plugins": [["babel-plugin-jsx-dom-expressions", {moduleName: 'mobx-jsx'}]]

See plugin options

For TS JSX types add to your

tsconfig.json

"jsx": "preserve",
"jsxImportSource": "mobx-jsx"

Installation

> npm install mobx-jsx babel-plugin-jsx-dom-expressions

Examples

• Counter Using Functions
• Counter Using Classes
• Lazy Loading
• Context

API

MobX JSX works both with function and Class components (extend Component from this library).

Map For Observable Arrays

Ships a specialize map function for optimal list rendering that takes an observable array as it's first argument. To avoid re-rendering the complete list on changes.

import { map } from "mobx-jsx";

const list = observable(["Alpha", "Beta", "Gamma"]);

{map(list, item => (
• {item}
))}

Lifecycles

Unlike React

render

render

However, you may emulate

componentDidMount

componentWillUnmount

Promise

cleanup

Example

import { render, cleanup, Component as _Component } from "mobx-jsx";

class Component extends _Component {
  constructor(props) {
    super(props);
    if (this.componentDidMount) {
      Promise.resolve().then(() => this.componentDidMount());
    }
    if (this.componentWillUnmount) {
      cleanup(() => this.componentWillUnmount());
    }
  }
}
class App extends Component {
  componentDidMount() {
    console.log("componentDidMount");
  }
  componentWillUnmount() {
    console.log("componentWillUnmount");
  }
}

Lazily Loading a Component

import { render, lazy } from "mobx-jsx";

// use lazy to allow code splitting
const SomeComponent = lazy(() => import("./SomeComponent"));
function App() {
  return (
    <>
      
    >
  );
}
render(App, document.body);

MobX JSX also supports a Context API.

Non-precompiled environments

Alternatively supports Tagged Template Literals or HyperScript for non-precompiled environments by installing the companion library and including variants:

import { html } from "mobx-jsx/html"; // or
import { h } from "mobx-jsx/h";

There is a small performance overhead of using these runtimes but the performance is still very impressive. Tagged Template solution is much more performant that the HyperScript version, but HyperScript opens up compatibility with some companion tooling like:

• HyperScript Helpers Use an element as functions DSL
• Babel Plugin HTM Transpile Tagged Template Literals to HyperScript for IE11 compatibility

Further documentation available at: Lit DOM Expressions and Hyper DOM Expressions.