stringjsx

Render JSX to HTML

This library allows you to write jsx syntax but transform it into a string at runtime. It also sanitizes any interpolated strings, unlike using template strings, where you would need to do so manually.

Installation

Put in your package.json "dependencies":

{
  // ...
  "stringjsx": "^4.0.1",
  // ...
}

Or use npm:

npm install --save stringjsx

Or yarn:

yarn add stringjsx

Or pnpm:

pnpm install stringjsx

Usage

Configuration

In order for stringjsx to work you need a compiler supporting jsx, which comes with some options.

If, for example, you have a tsconfig.json, it should contain:

{
  // ...
  "compilerOptions": {
    // ...
    "jsx": "react",
    "jsxFactory": "h",
    "jsxFragmentFactory": "h.Fragment",
    // ...
  },
  // ...
}

What matters is that h is the default export from the stringjsx package and that your compiler knows to use that name for all your jsx code.

The FragmentFactory should in some way be set to <default export>.Fragment.

You may also be able to configure your compiler to inject the import line.

Writing jsx

Now you can render jsx to strings in your code:

document.body.innerHTML = <div>
  <p>this is my dom</p>
  <p>haha</p>
</div>

If you configured your fragment factory correctly you should also be able to do fragments:

function f1() {
  return (<>
    <div>three</div>
    <div>root</div>
    <div>elements</div>
  </>)
}

document.body.innerHTML = <div>
  {f1()}
  <p>success!</p>
</div>

tsx

Since the package comes with types you should be able to just use it as is. Note that the type checking may not be perfect.

const coolDOMString: string = <div>my div</div>;

Also, keep in mind that the library actually returns a String and not a string. Depending on your use case this may be a problem.

"Component" rendering

stringjsx serializes JSX directly to HTML. However, it's still possible to create a basic kind of Pure Functional Components as a sort of "template partial".

When stringjsx is given a Function as the JSX tag name, it will invoke that function and pass it { children, ...props }. This is the same signature as a Pure Functional Component in react/preact, except children is an Array of already-serialized HTML strings.

This actually means it's possible to build compositional template modifiers with these simple Components, or even higher-order components.

Here's a more complex example that uses a component to encapsulate iteration items:

let items = ['one', 'two'];

const Item = ({ item, index, children }) => (
  <li id={index}>
    <h4>{item}</h4>
    {children}
  </li>
);

console.log(
  <div class="foo">
    <h1>Hi!</h1>
    <ul>
      { items.map( (item, index) => (
        <Item {...{ item, index }}>
          This is item {item}!
        </Item>
      )) }
    </ul>
  </div>
);

The above outputs the following HTML:

<div class="foo">
  <h1>Hi!</h1>
  <ul>
    <li id="0">
      <h4>one</h4>This is item one!
    </li>
    <li id="1">
      <h4>two</h4>This is item two!
    </li>
  </ul>
</div>

Sanitization

stringjsx sanitizes html for you:

const username = '<script>alert("hacked");</script>'

const html = <div><span>{username}</span></div>;

becomes:

<div><span>&lt;script&gt;alert(&quot;hacked&quot;);&lt;/script&gt;</span></div>

Skipping sanitization

To skip sanitization you have two options:

dangerouslySetInnerHTML

const username = '<script>alert("hacked");</script>'

const html = <div>
  <span dangerouslySetInnerHTML={{__html: username}}>this will be overwritten</span>
</div>;

This will also overwrite any content you put in that element normally.

_stringjsx_sanitized

const username = new String('<script>alert("hacked");</script>');
username._stringjsx_sanitized = true;

const html = <div><span>{username}</span></div>;

Note: you must use the String constructor to do this.

Credits

• Jason Miller (original creator of vhtml)
• Odin (created stringjsx from vhtml, rewrote the code for readability, pulling in improvements from other forks)

Setting up for development

Contribution/maintenance instructions follow.

• $ asdf install (Use nodejs version as specified in .tool-versions)
• $ npm install
• $ npm test

You may want to install your development version of stringjsx in a real project for testing:

// package.json
"stringjsx": "file:~/path/to/this/repo",

Contributing

• Fork
• Add tests
• Make your changes
• Add or change any documentation
• Add an unreleased entry to the changelog
• Make sure the benchmark compares favourably to vhtml
• Submit your pull request

Benchmarking

• $ npm run bench
• $ node tmp/bench.node.js
• OR open bench.html in browser

Version bumping

• Update the changelog
• $ npm version patch|minor|major
• $ npm run prepare (make sure the tests are passing!)
• $ npm publish