react/packages/react-is
Andrew Clark 857ee8cdf9
Don't minify symbols in production builds (#28881)
This disables symbol renaming in production builds. The original
variable and function names are preserved. All other forms of
compression applied by Closure (dead code elimination, inlining, etc)
are unchanged — the final program is identical to what we were producing
before, just in a more readable form.

The motivation is to make it easier to debug React issues that only
occur in production — the same reason we decided to start shipping
sourcemaps in #28827 and #28827.

However, because most apps run their own minification step on their npm
dependencies, it's not necessary for us to minify the symbols before
publishing — it'll be handled the app, if desired.

This is the same strategy Meta has used to ship React for years. The
React build itself has unminified symbols, but they get minified as part
of Meta's regular build pipeline.

Even if an app does not minify their npm dependencies, gzip covers most
of the cost of symbol renaming anyway.

This saves us from having to ship sourcemaps, which means even apps that
don't have sourcemaps configured will be able to debug the React build
as easily as they would any other npm dependency.
2024-04-20 11:23:46 -04:00
..
npm Don't minify symbols in production builds (#28881) 2024-04-20 11:23:46 -04:00
src Remove React.createFactory (#27798) 2024-03-29 16:29:48 -04:00
index.experimental.js Remove deprecated methods from react-is (#28224) 2024-02-11 00:25:17 +00:00
index.js [Codemod] Update copyright header to Meta (#25315) 2022-10-18 11:19:24 -04:00
index.stable.js Remove deprecated methods from react-is (#28224) 2024-02-11 00:25:17 +00:00
package.json [UMD] Remove umd builds (#28735) 2024-04-17 11:15:27 -07:00
README.md Remove React.createFactory (#27798) 2024-03-29 16:29:48 -04:00

react-is

This package allows you to test arbitrary values and see if they're a particular React element type.

Installation

# Yarn
yarn add react-is

# NPM
npm install react-is

Usage

Determining if a Component is Valid

import React from "react";
import * as ReactIs from "react-is";

class ClassComponent extends React.Component {
  render() {
    return React.createElement("div");
  }
}

const FunctionComponent = () => React.createElement("div");

const ForwardRefComponent = React.forwardRef((props, ref) =>
  React.createElement(Component, { forwardedRef: ref, ...props })
);

const Context = React.createContext(false);

ReactIs.isValidElementType("div"); // true
ReactIs.isValidElementType(ClassComponent); // true
ReactIs.isValidElementType(FunctionComponent); // true
ReactIs.isValidElementType(ForwardRefComponent); // true
ReactIs.isValidElementType(Context.Provider); // true
ReactIs.isValidElementType(Context.Consumer); // true

Determining an Element's Type

Context

import React from "react";
import * as ReactIs from 'react-is';

const ThemeContext = React.createContext("blue");

ReactIs.isContextConsumer(<ThemeContext.Consumer />); // true
ReactIs.isContextProvider(<ThemeContext.Provider />); // true
ReactIs.typeOf(<ThemeContext.Provider />) === ReactIs.ContextProvider; // true
ReactIs.typeOf(<ThemeContext.Consumer />) === ReactIs.ContextConsumer; // true

Element

import React from "react";
import * as ReactIs from 'react-is';

ReactIs.isElement(<div />); // true
ReactIs.typeOf(<div />) === ReactIs.Element; // true

Fragment

import React from "react";
import * as ReactIs from 'react-is';

ReactIs.isFragment(<></>); // true
ReactIs.typeOf(<></>) === ReactIs.Fragment; // true

Portal

import React from "react";
import ReactDOM from "react-dom";
import * as ReactIs from 'react-is';

const div = document.createElement("div");
const portal = ReactDOM.createPortal(<div />, div);

ReactIs.isPortal(portal); // true
ReactIs.typeOf(portal) === ReactIs.Portal; // true

StrictMode

import React from "react";
import * as ReactIs from 'react-is';

ReactIs.isStrictMode(<React.StrictMode />); // true
ReactIs.typeOf(<React.StrictMode />) === ReactIs.StrictMode; // true