gem-hunter

Turn a ReactElement into the corresponding JSX string.

Useful for unit testing and any other need you may think of.

Features:

• supports nesting and deep nesting like <div a={{b: {c: {d: <div />}}}} />
• props: supports string, number, function (inlined as prop={function noRefCheck() {}}), object, ReactElement (inlined), regex, booleans (with or without shorthand syntax), ...
• order props alphabetically
• sort object keys in a deterministic order (o={{a: 1, b:2}} === o={{b:2, a:1}})
• handle ref and key attributes, they are always on top of props
• React's documentation indent style for JSX

npm install react-element-to-jsx-string [--save-dev]

import React from 'react';
import reactElementToJSXString from 'react-element-to-jsx-string';

console.log(reactElementToJSXString(<div a="1" b="2">Hello, world!</div>));
// <div
//   a="1"
//   b="2"
// >
//   Hello, world!
// </div>

options.displayName: function(ReactElement)

Provide a different algorithm in charge of finding the right display name (name of the underlying Class) for your element.

Just return the name you want for the provided ReactElement, as a string.

options.filterProps: string[] | (value: unknown, key: string) => boolean, default []

If an array of strings is passed, filter out any prop who's name is in the array. For example ['key'] will suppress the key="" prop from being added.

If a function is passed, it will be called for each prop with two arguments, the prop value and key, and will filter out any that return false.

options.showDefaultProps: boolean, default true

If true, default props shown.

If false, default props are omitted unless they differ from from the default value.

options.showFunctions: boolean, default false

If true, functions bodies are shown.

If false, functions bodies are replaced with function noRefCheck() {}.

options.functionValue: function, default inlineFunction

Allows you to override the default formatting of function values.

functionValue receives the original function reference as input and should send any value as output. The value is converted to a string.

Two formatters are exported:

• inlineFunction (the default) puts the function source on one line.
• preserveFunctionLineBreak keeps the function source as written.

import reactElementToJSXString, { preserveFunctionLineBreak } from 'react-element-to-jsx-string';

reactElementToJSXString(element, { showFunctions: true, functionValue: preserveFunctionLineBreak });

options.tabStop: number, default 2

Provide a different number of columns for indentation.

options.useBooleanShorthandSyntax: boolean, default true

If true, true prop values use the shorthand syntax: prop instead of prop={true}.

If false, Boolean prop values will be explicitly output like prop={true} and prop={false}

options.maxInlineAttributesLineLength: number, default undefined

Allows to render multiple attributes on the same line and control the behaviour.

You can provide the max number of characters to render inline with the tag name. If the number of characters on the line (including spacing and the tag name) exceeds this number, then all attributes will be rendered on a separate line. The default value of this option is undefined. If this option is undefined then if there is more than one attribute on an element, they will render on their own line. Note: Objects passed as attribute values are always rendered on multiple lines

options.sortProps: boolean, default true

Either to sort or not props. If you use this lib to make some isomorphic rendering you should set it to false, otherwise this would lead to react invalid checksums as the prop order is part of react isomorphic checksum algorithm.

options.useFragmentShortSyntax: boolean, default true

If true, fragment will be represented with the JSX short syntax <>...</> (when possible).

If false, fragment will always be represented with the JSX explicit syntax <React.Fragment>...</React.Fragment>.

According to the specs:

• A keyed fragment will always use the explicit syntax: <React.Fragment key={...}>...</React.Fragment>
• An empty fragment will always use the explicit syntax: <React.Fragment />

react-element-to-jsx-string is published as an ES module only, with its TypeScript types included.

• React: 19 or later (react, react-dom and react-is are peer dependencies).
• Node.js: 24 or later.
• Browsers: any browser that supports ES2020, such as Chrome and Edge 80, Firefox 74 and Safari 13.1, or later versions.
• Bundlers (Vite, webpack 5, Rollup, esbuild…): any version that supports the exports field of package.json.
• TypeScript: use "moduleResolution": "bundler", "node16" or "nodenext".

Use import to load it:

import reactElementToJSXString from 'react-element-to-jsx-string';

CommonJS code can still require() it. The default export is then on .default:

const reactElementToJSXString = require('react-element-to-jsx-string').default;

The project uses pnpm and Node.js 24 or later.

pnpm install
pnpm test             # unit tests, in watch mode
pnpm run typecheck
pnpm run lint         # oxlint (pnpm run lint:fix to fix)
pnpm run format       # oxfmt check (pnpm run format:fix to fix)

Smoke test: install the built package in a temporary project with a given React version, and check it works.

pnpm run build
pnpm run smoke 19.0.0  # or latest, next…

pnpm run build

Releases are made with Changesets.

1. In a pull request that changes the package, add a changeset: choose the version bump (patch, minor or major, see https://semver.org/) and describe the change for the changelog.

   pnpm changeset

2. Once merged on master, the changeset is added to a "Version Packages" pull request, which updates the version and CHANGELOG.md.

3. Merging the "Version Packages" pull request publishes the package to npm from GitHub Actions, and creates the git tag and the GitHub release.

alexlande/react-to-jsx was a good source of inspiration.

We built our own module because we had some needs like ordering props in alphabetical order.