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An extremely fast, React-like JavaScript library for building modern user interfaces
Filed under application tools › frameworksInferno is an insanely fast, React-like library for building high-performance user interfaces on both the client and server.
Description
The main objective of the InfernoJS project is to provide the fastest possible runtime performance for web applications. Inferno excels at rendering real time data views or large DOM trees.
The performance is achieved through multiple optimizations, for example:
- Inferno's own JSX plugin creates monomorphic
createVNode
calls, instead ofcreateElement
- Inferno's diff process uses bitwise flags to memoize the shape of objects
- Child nodes are normalized only when needed
- Special JSX flags can be used during compile time to optimize runtime performance at application level
- Many micro optimizations
Features
- Component driven + one-way data flow architecture
- React-like API, concepts and component lifecycle events
- Partial synthetic event system, normalizing events for better cross browser support
- Inferno's
linkEvent
feature removes the need to use arrow functions or binding event callbacks - Isomorphic rendering on both client and server with
inferno-server
- Unlike React and Preact, Inferno has lifecycle events on functional components
- Unlike Preact and other React-like libraries, Inferno has controlled components for input/select/textarea elements
- Components can be rendered outside their current html hierarchy using
createPortal
- API - Support for older browsers without any polyfills
- defaultHooks for Functional components, this way re-defining lifecycle events per usage can be avoided
- Inferno supports setting styles using string
<div style="background-color: red"></div>
or using object literal syntax<div style={{"background-color": "red"}}></div>
. For camelCase syntax support seeinferno-compat
. - Fragments (v6)
- createRef and forwardRef APIs (v6)
- componentDidAppear, componentWillDisappear and componentWillMove (v8) - class and function component callbacks to ease animation work, see inferno-animation package
Browser support
Since version 4 we have started running our test suite without any polyfills. Inferno is now part of Saucelabs open source program and we use their service for executing the tests.
InfernoJS is actively tested with browsers listed below, however it may run well on older browsers as well. This is due to limited support of browser versions in recent testing frameworks. https://github.com/jasmine/jasmine/blob/main/release_notes/5.0.0.md
Migration guides
Benchmarks
Live examples at https://infernojs.github.io/inferno
Code Example
Let's start with some code. As you can see, Inferno intentionally keeps the same design ideas as React regarding components: one-way data flow and separation of concerns.
In these examples, JSX is used via the Inferno JSX Babel Plugin to provide a simple way to express Inferno virtual DOM. You do not need to use JSX, it's completely optional, you can use hyperscript or createElement (like React does). Keep in mind that compile time optimizations are available only for JSX.
import { render } from 'inferno'; const message = "Hello world"; render( <MyComponent message={ message } />, document.getElementById("app") );
Furthermore, Inferno also uses ES6 components like React:
import { render, Component } from 'inferno'; class MyComponent extends Component { constructor(props) { super(props); this.state = { counter: 0 }; } render() { return ( <div> <h1>Header!</h1> <span>Counter is at: { this.state.counter }</span> </div> ); } } render( <MyComponent />, document.getElementById("app") );
Because performance is an important aspect of this library, we want to show you how to optimize your application even further. In the example below we optimize diffing process by using JSX $HasVNodeChildren and $HasTextChildren to predefine children shape compile time. In the MyComponent render method there is a div that contains JSX expression
node
as its content. Due to dynamic nature of Javascript that variablenode
could be anything and Inferno needs to go through the normalization process to make sure there are no nested arrays or other invalid data. Inferno offers a feature called ChildFlags for application developers to pre-define the shape of vNode's child node. In this example case it is using$HasVNodeChildren
to tell the JSX compiler, that this vNode contains only single element or component vNode. Now inferno will not go into the normalization process runtime, but trusts the developer decision about the shape of the object and correctness of data. If this contract is not kept andnode
variable contains invalid value for the pre-defined shape (fe.null
), then application would crash runtime. There is also span-element in the same render method, which content is set dynamically through_getText()
method. There$HasTextChildren
child-flag fits nicely, because the content of that given "span" is never anything else than text. All the available child flags are documented here.import { createTextVNode, render, Component } from 'inferno'; class MyComponent extends Component { constructor(props) { super(props); this.state = { counter: 0 }; } _getText() { return 'Hello!'; } render() { const node = this.state.counter > 0 ? <div>0</div> : <span $HasTextChildren>{this._getText()}</span>; return ( <div> <h1>Header!</h1> <div $HasVNodeChildren>{node}</div> </div> ); } } render( <MyComponent />, document.getElementById("app") );
Tear down
To tear down inferno application you need to render null on root element. Rendering
null
will trigger unmount lifecycle hooks for whole vDOM tree and remove global event listeners. It is important to unmount unused vNode trees to free browser memory.import { createTextVNode, render, Component } from 'inferno'; const rootElement = document.getElementById("app"); // Start the application render( <ExampleComponent/>, rootElement ); // Tear down render( null, rootElement );
More Examples
If you have built something using Inferno you can add them here:
- Simple Clock (@JSFiddle)
- Simple JS Counter (@github/scorsi): SSR Inferno (view) + Cerebral (state manager) + FuseBox (build system/bundler)
- Online interface to TMDb movie database (@codesandbox.io): Inferno + Inferno hyperscript (view) + Superagent (network requests) + Web component (custom elements v1) + state-transducer (state machine library)
- Lemmy - a self-hostable reddit alternative (front end in Inferno)
Getting Started
The easiest way to get started with Inferno is by using Create Inferno App.
Alternatively, you can try any of the following:
- the Inferno Boilerplate for a very simple setup.
- for a more advanced example demonstrating how Inferno might be used, we recommend trying out Inferno Starter Project by nightwolfz.
- for using Inferno to build a mobile app, try Inferno Mobile Starter Project by Rudy-Zidan.
- for TypeScript support and bundling, check out ts-plugin-inferno, or inferno-typescript-example.
- for an example of how to use Inferno in codesandbox: https://codesandbox.io/s/znmyj24w4p
- for using parcel and typescript
Core package:
npm install --save inferno
Addons:
# server-side rendering npm install --save inferno-server # routing npm install --save inferno-router
Pre-bundled files for browser consumption can be found on our cdnjs:
Or on jsDelivr:
https://cdn.jsdelivr.net/npm/inferno@latest/dist/inferno.min.js
Or on unpkg.com:
https://unpkg.com/inferno@latest/dist/inferno.min.js
Creating Virtual DOM
JSX:
npm install --save-dev babel-plugin-inferno
Hyperscript:
npm install --save inferno-hyperscript
createElement:
npm install --save inferno-create-element
Compatibility with existing React apps
npm install --save-dev inferno-compat
Note: Make sure you read more about
inferno-compat
before using it.Third-party state libraries
Inferno now has bindings available for some of the major state management libraries out there:
- Redux via
inferno-redux
- MobX via
inferno-mobx
- Cerebral via
@cerebral/inferno
JSX
Inferno has its own JSX Babel plugin.
Differences from React
- Inferno doesn't have a fully synthetic event system like React does. Inferno has a partially synthetic event system, instead opting to only delegate certain events (such as
onClick
). - Inferno doesn't support React Native. Inferno was only designed for the browser/server with the DOM in mind.
- Inferno doesn't support legacy string refs, use
createRef
or callbackref
API - Inferno provides lifecycle events on functional components. This is a major win for people who prefer lightweight components rather than ES2015 classes.
Differences from Preact
- Inferno has a partial synthetic event system, resulting in better performance via delegation of certain events.
- Inferno is much faster than Preact in rendering, updating and removing elements from the DOM. Inferno diffs against virtual DOM, rather than the real DOM (except when loading from server-side rendered content), which means it can make drastic improvements. Unfortunately, diffing against the real DOM has a 30-40% overhead cost in operations.
- Inferno fully supports controlled components for
input
/select
/textarea
elements. This prevents lots of edgecases where the virtual DOM is not the source of truth (it should always be). Preact pushes the source of truth to the DOM itself. - Inferno provides lifecycle events on functional components. This is a major win for people who prefer lightweight components rather than ES2015 classes.
Event System
Like React, Inferno also uses a light-weight synthetic event system in certain places (although both event systems differ massively). Inferno's event system provides highly efficient delegation and an event helper called
linkEvent
.One major difference between Inferno and React is that Inferno does not rename events or change how they work by default. Inferno only specifies that events should be camel cased, rather than lower case. Lower case events will bypass Inferno's event system in favour of using the native event system supplied by the browser. For example, when detecting changes on an
<input>
element, in React you'd useonChange
, with Inferno you'd useonInput
instead (the native DOM event isoninput
).Available synthetic events are:
onClick
onDblClick
onFocusIn
onFocusOut
onKeyDown
onKeyPress
onKeyUp
onMouseDown
onMouseMove
onMouseUp
onTouchEnd
onTouchMove
onTouchStart
linkEvent
(package:inferno
)linkEvent()
is a helper function that allows attachment ofprops
/state
/context
or other data to events without needing tobind()
them or use arrow functions/closures. This is extremely useful when dealing with events in functional components. Below is an example:import { linkEvent } from 'inferno'; function handleClick(props, event) { props.validateValue(event.target.value); } function MyComponent(props) { return <div><input type="text" onClick={ linkEvent(props, handleClick) } /><div>; }
This is an example of using it with ES2015 classes:
import { linkEvent, Component } from 'inferno'; function handleClick(instance, event) { instance.setState({ data: event.target.value }); } class MyComponent extends Component { render () { return <div><input type="text" onClick={ linkEvent(this, handleClick) } /><div>; } }
linkEvent()
offers better performance than binding an event in a class constructor and using arrow functions, so use it where possible.Controlled Components
In HTML, form elements such as
<input>
,<textarea>
, and<select>
typically maintain their own state and update it based on user input. In Inferno, mutable state is typically kept in the state property of components, and only updated withsetState()
.We can combine the two by making the Inferno state be the "single source of truth". Then the Inferno component that renders a form also controls what happens in that form on subsequent user input. An input form element whose value is controlled by Inferno in this way is called a "controlled component".
Inferno Top-Level API
render
(package:inferno
)import { render } from 'inferno'; render(<div />, document.getElementById("app"));
Render a virtual node into the DOM in the supplied container given the supplied virtual DOM. If the virtual node was previously rendered into the container, this will perform an update on it and only mutate the DOM as necessary, to reflect the latest Inferno virtual node.
Warning: If the container element is not empty before rendering, the content of the container will be overwritten on the initial render.
createRenderer
(package:inferno
)createRenderer
creates an alternative render function with a signature matching that of the first argument passed to a reduce/scan function. This allows for easier integration with reactive programming libraries, like RxJS and Most.import { createRenderer } from 'inferno'; import { scan, map } from 'most'; const renderer = createRenderer(); // NOTE: vNodes$ represents a stream of virtual DOM node updates scan(renderer, document.getElementById("app"), vNodes$);
See inferno-most-fp-demo for an example of how to build an app architecture around this.
createElement
(package:inferno-create-element
)Creates an Inferno VNode using a similar API to that found with React's
createElement()
import { Component, render } from 'inferno'; import { createElement } from 'inferno-create-element'; class BasicComponent extends Component { render() { return createElement('div', { className: 'basic' }, createElement('span', { className: this.props.name }, 'The title is ', this.props.title) ) } } render( createElement(BasicComponent, { title: 'abc' }), document.getElementById("app") );
Component
(package:inferno
)Class component:
import { Component } from 'inferno'; class MyComponent extends Component { render() { return <div>My Component</div> } }
This is the base class for Inferno Components when they're defined using ES6 classes.
Functional component:
const MyComponent = ({ name, age }) => ( <span>My name is: { name } and my age is: {age}</span> );
Another way of using defaultHooks.
export function Static() { return <div>1</div>; } Static.defaultHooks = { onComponentShouldUpdate() { return false; } };
Default props
export function MyFunctionalComponent({value}) { return <div>{value}</div>; } MyFunctionalComponent.defaultProps = { value: 10 };
Functional components are first-class functions where their first argument is the
props
passed through from their parent.createVNode
(package:inferno
)import { createVNode } from 'inferno'; createVNode( flags, type, [className], [...children], [childFlags], [props], [key], [ref] )
createVNode is used to create html element's virtual node object. Typically
createElement()
(package:inferno-create-element
),h()
(package:inferno-hyperscript
) or JSX are used to createVNode
s for Inferno, but under the hood they all usecreateVNode()
. Below is an example ofcreateVNode
usage:import { VNodeFlags, ChildFlags } from 'inferno-vnode-flags'; import { createVNode, createTextVNode, render } from 'inferno'; const vNode = createVNode(VNodeFlags.HtmlElement, 'div', 'example', createTextVNode('Hello world!'), ChildFlags.HasVNodeChildren); // <div class="example">Hello world!</div> render(vNode, container);
createVNode
arguments explained:flags
: (number) is a value fromVNodeFlags
, this is a numerical value that tells Inferno what the VNode describes on the page.type
: (string) is tagName for element for example 'div'className
: (string) is the class attribute ( it is separated from props because it is the most commonly used property )children
: (vNode[]|vNode) is one or array of vNodes to be added as children for this vNodechildFlags
: (number) is a value fromChildFlags
, this tells inferno shape of the children so normalization process can be skipped.props
: (Object) is object containing all other properties. fe:{onClick: method, 'data-attribute': 'Hello Community!}
key
: (string|number) unique key within this vNodes siblings to identify it during keyed algorithm.ref
: (function) callback which is called when DOM node is added/removed from DOM.createComponentVNode
(package: 'inferno')import { createComponentVNode } from 'inferno'; createComponentVNode( flags, type, [props], [key], [ref] )
createComponentVNode is used for creating vNode for Class/Functional Component.
Example:
import { VNodeFlags, ChildFlags } from 'inferno-vnode-flags'; import { createVNode, createTextVNode, createComponentVNode, render } from 'inferno'; function MyComponent(props, context) { return createVNode(VNodeFlags.HtmlElement, 'div', 'example', createTextVNode(props.greeting), ChildFlags.HasVNodeChildren); } const vNode = createComponentVNode(VNodeFlags.ComponentFunction, MyComponent, { greeting: 'Hello Community!' }, null, { onComponentDidMount() { console.log("example of did mount hook!") } }) // <div class="example">Hello Community!</div> render(vNode, container);
createComponentVNode
arguments explained:flags
: (number) is a value fromVNodeFlags
, this is a numerical value that tells Inferno what the VNode describes on the page.type
: (Function/Class) is the class or function prototype for Componentprops
: (Object) properties passed to Component, can be anythingkey
: (string|number) unique key within this vNodes siblings to identify it during keyed algorithm.ref
: (Function|Object) this property is object for Functional Components defining all its lifecycle methods. For class Components this is function callback for ref.createTextVNode
(package: 'inferno')createTextVNode is used for creating vNode for text nodes.
createTextVNode
arguments explained: text: (string) is a value for text node to be created. key: (string|number) unique key within this vNodes siblings to identify it during keyed algorithm.import { createTextVNode } from 'inferno'; createTextVNode( text, key )
cloneVNode
(package:inferno-clone-vnode
)This package has same API as React.cloneElement
import { cloneVNode } from 'inferno-clone-vnode'; cloneVNode( vNode, [props], [...children] )
Clone and return a new Inferno
VNode
using aVNode
as the starting point. The resultingVNode
will have the originalVNode
's props with the new props merged in shallowly. New children will replace existing children. key and ref from the originalVNode
will be preserved.cloneVNode()
is almost equivalent to:<VNode.type {...VNode.props} {...props}>{children}</VNode.type>
An example of using
cloneVNode
:import { createVNode, render } from 'inferno'; import { cloneVNode } from 'inferno-clone-vnode'; import { VNodeFlags } from 'inferno-vnode-flags'; const vNode = createVNode(VNodeFlags.HtmlElement, 'div', 'example', 'Hello world!'); const newVNode = cloneVNode(vNode, { id: 'new' }); // we are adding an id prop to the VNode render(newVNode, container);
If you're using JSX:
import { render } from 'inferno'; import { cloneVNode } from 'inferno-clone-vnode'; const vNode = <div className="example">Hello world</div>; const newVNode = cloneVNode(vNode, { id: 'new' }); // we are adding an id prop to the VNode render(newVNode, container);
createPortal
(package: 'inferno')HTML:
<div id="root"></div> <div id="outside"></div>
Javascript:
const { render, Component, version, createPortal } from 'inferno'; function Outsider(props) { return <div>{`Hello ${props.name}!`}</div>; } const outsideDiv = document.getElementById('outside'); const rootDiv = document.getElementById('root'); function App() { return ( <div> Main view ... {createPortal(<Outsider name="Inferno" />, outsideDiv)} </div> ); } // render an instance of Clock into <body>: render(<App />, rootDiv);
Results into:
<div id="root"> <div>Main view ...</div> </div> <div id="outside"> <div>Hello Inferno!</div> </div>
Cool, huh? Updates (props/context) will flow into "Outsider" component from the App component the same way as any other Component. For inspiration on how to use it click here!
createRef
(package:inferno
)createRef API provides shorter syntax than callback ref when timing of element is not needed.
import { Component, render, createRef } from 'inferno'; class Foobar extends Component { constructor(props) { super(props); // Store reference somewhere this.element = createRef(); // Returns object {current: null} } render() { return ( <div> <span id="span" ref={this.element}> Ok </span> </div> ); } } render(<Foobar />, container);
createFragment
(package:inferno
)createFragment is the native way to createFragment vNode.
createFragment(children: any, childFlags: ChildFlags, key?: string | number | null)
createFragment
arguments explained:children
: (Array) Content of fragment vNode, typically array of VNodeschildFlags
: (number) is a value fromChildFlags
, this tells inferno shape of the children so normalization process can be skipped.key
: (string|number) unique key within this vNodes siblings to identify it during keyed algorithm.Alternative ways to create fragment vNode are:
- Using JSX
<> ... </>
,<Fragment> .... </Fragment>
or<Inferno.Fragment> ... </Inferno.Fragment>
- Using createElement API
createElement(Inferno.Fragment, {key: 'test'}, ...children)
- Using hyperscript API
h(Inferno.Fragment, {key: 'test'}, children)
In the below example both fragments are identical except they have different key
import { Fragment, render, createFragment } from 'inferno'; import { ChildFlags } from 'inferno-vnode-flags'; function Foobar() { return ( <div $HasKeyedChildren> {createFragment( [<div>Ok</div>, <span>1</span>], ChildFlags.HasNonKeyedChildren, 'key1' )} <Fragment key="key2"> <div>Ok</div> <span>1</span> </Fragment> </div> ); } render(<Foobar />, container);
forwardRef
(package:inferno
)forwardRef is a new mechanism to "forward" ref inside a functional Component. It can be useful if you have simple functional Components and you want to create reference to a specific element inside it.
import { forwardRef, Component, render } from 'inferno'; const FancyButton = forwardRef((props, ref) => ( <button ref={ref} className="FancyButton"> {props.children} </button> )); class Hello extends Component { render() { return ( <FancyButton ref={btn => { if (btn) { // btn variable is the button rendered from FancyButton } }} > Click me! </FancyButton> ); } } render(<Hello />, container);
hydrate
(package:inferno-hydrate
)import { hydrate } from 'inferno-hydrate'; hydrate(<div />, document.getElementById("app"));
Same as
render()
, but is used to hydrate a container whose HTML contents were rendered byinferno-server
. Inferno will attempt to attach event listeners to the existing markup.options.componentComparator
( packageinferno
) DEV onlyThis option can be used during development to create custom component comparator method. This option will be called on every Component update. It gets two parameters: lastVNode and nextVNode. When it returns
true
lastVNode will be replaced with nextVNode. If anything else thantrue
is returned it falls to normal behavior.import {options} from 'inferno'; options.componentComparator = function (lastVNode, nextVNode) { /* custom logic */ return true; // Replaces lastVNode with nextVNode }
findDOMNode
(package:inferno-extras
)This feature has been moved from inferno to inferno-compat in v6. No options are needed anymore.
Note: we recommend using a
ref
callback on a component to find its instance, rather than usingfindDOMNode()
.findDOMNode()
cannot be used on functional components.If a component has been mounted into the DOM, this returns the corresponding native browser DOM element. This method is useful for reading values out of the DOM, such as form field values and performing DOM measurements. In most cases, you can attach a ref to the DOM node and avoid using
findDOMNode()
at all. When render returns null or false,findDOMNode()
returns null. If Component has rendered fragment it returns the first element.Inferno Flags (package: inferno-vnode-flags)
VNodeFlags:
VNodeFlags.HtmlElement
VNodeFlags.ComponentUnknown
VNodeFlags.ComponentClass
VNodeFlags.ComponentFunction
VNodeFlags.Text
VNodeFlags.SvgElement
VNodeFlags.InputElement
VNodeFlags.TextareaElement
VNodeFlags.SelectElement
VNodeFlags.Portal
VNodeFlags.ReCreate
(JSX $ReCreate) always re-creates the vNodeVNodeFlags.ContentEditable
VNodeFlags.Fragment
VNodeFlags.InUse
VnodeFlags.ForwardRef
VNodeFlags.Normalized
VNodeFlags Masks:
VNodeFlags.ForwardRefComponent
Functional component wrapped in forward refVNodeFlags.FormElement
- Is form elementVNodeFlags.Element
- Is vNode elementVNodeFlags.Component
- Is vNode ComponentVNodeFlags.DOMRef
- Bit set when vNode holds DOM referenceVNodeFlags.InUseOrNormalized
- VNode is used somewhere else or came from normalization processVNodeFlags.ClearInUseNormalized
- Opposite mask of InUse or Normalized
ChildFlags
ChildFlags.UnknownChildren
needs NormalizationChildFlags.HasInvalidChildren
is invalid (null, undefined, false, true)ChildFlags.HasVNodeChildren
(JSX $HasVNodeChildren) is single vNode (Element/Component)ChildFlags.HasNonKeyedChildren
(JSX $HasNonKeyedChildren) is Array of vNodes non keyed (no nesting, no holes)ChildFlags.HasKeyedChildren
(JSX $HasKeyedChildren) is Array of vNodes keyed (no nesting, no holes)ChildFlags.HasTextChildren
(JSX $HasTextChildren) vNode contains only text
ChildFlags Masks
ChildFlags.MultipleChildren
Is Array
renderToString
(package:inferno-server
)import { renderToString } from 'inferno-server'; const string = renderToString(<div />);
Render a virtual node into an HTML string, given the supplied virtual DOM.
Functional component lifecycle events
Name Triggered when Arguments to callback onComponentWillMount
a functional component is about to mount onComponentDidMount
a functional component has mounted successfully domNode
onComponentShouldUpdate
a functional component has been triggered to update lastProps, nextProps
onComponentWillUpdate
a functional component is about to perform an update lastProps, nextProps
onComponentDidUpdate
a functional component has performed an update lastProps, nextProps
onComponentWillUnmount
a functional component is about to be unmounted domNode
onComponentDidAppear
a functional component has mounted and is ready for animations domNode, props
onComponentWillDisappear
a functional component is unmounted before DOM node is removed domNode, props, callback
onComponentWillDisappear has special type of argument "callback" which needs to be called when component is ready to be removed from the DOM. fe. after animations are finished.
Class component lifecycle events
All these Component lifecycle methods ( including
render
andsetState - callback
) are called with Component instance context. You don't need to "bind" these methods.Name Triggered when Arguments to callback componentDidMount
component has been mounted successfully componentWillMount
component is about to mount componentWillReceiveProps
before render when component updates nextProps, context
shouldComponentUpdate
component has been triggered to update nextProps, nextState
componentWillUpdate
component is about to perform an update nextProps, nextState, context
componentDidUpdate
component has performed an update lastProps, lastState, snapshot
componentWillUnmount
component is about to be unmounted getChildContext
before render method, return value object is combined to sub tree context getSnapshotBeforeUpdate
before component updates, return value is sent to componentDidUpdate as 3rd parameter lastProps, lastState
static getDerivedStateFromProps
before render method nextProps, state
componentDidAppear
component has mounted and is ready for animations domNode
componentWillDisappear
component is unmounted before DOM node is removed domNode, callback
componentWillDisappear has special type of argument "callback" which needs to be called when component is ready to be removed from the DOM. fe. after animations are finished.
Using functional lifecycle events
Functional lifecycle events must be explicitly assigned via props onto a functional component like shown below:
import { render } from 'inferno'; function mounted(domNode) { // [domNode] will be available for DOM nodes and components (if the component has mounted to the DOM) } function FunctionalComponent({ props }) { return <div>Hello world</div>; } render( <FunctionalComponent onComponentDidMount={ mounted } />, document.getElementById("app") );
Please note: class components (ES2015 classes) from
inferno
do not support the same lifecycle events (they have their own lifecycle events that work as methods on the class itself).Development vs Production modes
By default, Inferno will run in development mode. Development mode provides extra checks and better error messages at the cost of slower performance and larger code to parse. When using Inferno in a production environment, it is highly recommended that you turn off development mode.
Running Inferno on Node JS
Ensure the environment variable
process.env.NODE_ENV
is set toproduction
.Application bundling
When building your application bundle, ensure
process.env.NODE_ENV
is replaced with string"development"
or"production"
based on the workflow. It is recommended to use ts-plugin-inferno for typescript TSX compilation and babel-plugin-infeno for javascript JSX compilation.When building for development, you may want to use
inferno.dev.esm.js
. That bundle file contains ES6 exports for better tree-shaking support, improved error messages and added validation to help fixing possible issues during development. The file is found frompackage.json
-dev:module
entry point and the file is physically located innode_modules/inferno/dist/index.dev.esm.js
. Remember that it is not recommended to use that file in production due to slower performance. For production usage usenode_modules/inferno/dist/inferno.esm.js
file.Example of Webpack configuration:
const path = require('path'); const infernoTsx = require('ts-plugin-inferno').default; ... webpack config ... module: { rules: [ { test: /\.js$/, // Add "jsx" if your application uses `jsx` file extensions exclude: /node_modules/, use: [{ loader: 'babel-loader', options: { plugins: [ // Compile javascript JSX syntax using inferno's own plugin ['babel-plugin-inferno', {imports: true}] ] } }] }, { test: /\.ts+(|x)$/, // Compile ts and tsx extensions exclude: /node_modules/, use: [{ loader: 'ts-loader', options: { getCustomTransformers: () => ({ // inferno custom TSX plugin after: [infernoTsx()] }), compilerOptions: { /* typescript compiler options */ } } }] } ] }, resolve: { extensions: ['.js', '.ts', '.tsx'], alias: { // This maps import "inferno" to es6 module entry based on workflow inferno: path.resolve(__dirname, 'node_modules/inferno/dist', isProduction ? 'index.dev.esm.js' : 'index.esm.js') } }, plugins: [ new webpack.DefinePlugin({ 'process.env': { 'NODE_ENV': JSON.stringify(isProduction ? 'production' : 'development') } }) ]
Example of Rollup configuration:
const path = require('path'); const alias = require('@rollup/plugin-alias'); const {babel} = require('@rollup/plugin-babel'); const replace = require('@rollup/plugin-replace'); const typescript = require('rollup-plugin-typescript2'); const transformInferno = require('ts-plugin-inferno').default; ... Rollup config ... { input: /* entry file */, plugins: [ alias({ resolve: ['.js'], entries: [ // This maps import "inferno" to es6 module entry based on workflow {find: 'inferno', replacement: path.resolve(__dirname, 'node_modules/inferno/dist', isProduction ? 'index.dev.esm.js' : 'index.esm.js')} ] }), typescript({ include: ['*.ts+(|x)', '**/*.ts+(|x)'], transformers: [ () => ({ after: [transformInferno()] }) ], tsconfig: 'tsconfig.json', tsconfigOverride: { /* typescript compiler options */ } }), babel({ babelrc: false, sourceMaps: isDeploy, plugins: [ // Compile javascript JSX syntax using inferno's own plugin ['babel-plugin-inferno', {imports: true}] ], babelHelpers: 'bundled' }) ] }
Custom namespaces
Inferno always wants to deliver great performance. In order to do so, it has to make intelligent assumptions about the state of the DOM and the elements available to mutate. Custom namespaces conflict with this idea and change the schema of how different elements and attributes might work, so Inferno makes no attempt to support namespaces. Instead, SVG namespaces are automatically applied to elements and attributes based on their
tag name
.Development
If you want to contribute code, fork this project and submit a PR from your fork. To run browser tests you need to build the repos. A complete rebuild of the repos can take >5 mins.
$ git clone git@github.com:infernojs/inferno.git $ cd inferno && npm i $ npm run test:node $ npm run build $ npm run test:browser
If you only want to run the browser tests when coding, use the following to reduce turnaround by 50-80%:
$ npm run quick-test:browser # Compiles all packages and runs browser tests $ npm run quick-test:browser-inferno # Only compiles the inferno package and runs browser tests $ npm run quick-test:browser-debug # Compiles all packages and runs browser tests with "debug"
Community
There is an InfernoJS Discord. You can join via https://discord.gg/SUKuhgaBpF.
Contributors
This project exists thanks to all the people who contribute. [Contribute].
Backers
Thank you to all our backers! 🙏 [Become a backer]
Sponsors
Support this project by becoming a sponsor. Your logo will show up here with a link to your website. [Become a sponsor]
- Inferno's own JSX plugin creates monomorphic