Typed HTML
HTML templates have never been this easy. Type safe using plain TypeScript with a minimal runtime footprint. No need to learn a template language, if you know TypeScript, you're set.
This:
// example.tsx
const item = 'item';
const icon = 'icon-add';
const ul = <ul>
<li>{item}</li>
</ul>;
typeof ul; // string
const button = <button onclick="handleClick">
<i class={icon}></i>
</button>;
typeof button; // string
console.log(ul);
console.log(button);Prints:
<ul>
<li>item</li>
</ul>
<button onclick="handleClick">
<i class="icon-add"></i>
</button>Getting started
Install:
npm install --save typed-htmlConfigure your TypeScript compiler for JSX:
{
"compilerOptions": {
"jsx": "react",
"jsxFactory": "elements.createElement"
}
}Although we're configuring the compiler to use React, this is not what is being used.
Instead, we redirect all jsx element to typed-html's elements.createElement.
Now create a *.tsx file. For example: example.tsx with the following content:
// example.tsx
import * as elements from 'typed-html';
const w = 'world';
const helloWorld = <p>Hello <strong>{w}</strong></p>;
typeof helloWorld; // => Just a string of courseHowever, the following piece of code will NOT compile:
<foo></foo>; // => Error: Property 'foo' does not exist on type 'JSX.IntrinsicElements'.
<a foo="bar"></a>; // => Error: Property 'foo' does not exist on type 'HtmlAnchorTag'Supported environments
Typed HTML supports both NodeJS and (since 2.0) the browser.
For use in the browser, either load typed-html as a module, or use a bundler like webpack or rollup to bundle the package for you.
// Direct ES import:
import * as elements from './node_modules/typed-html/dist/elements.js';
// OR, when using a bundler like rollup or webpack
import * as elements from 'typed-html';Supported scenarios
All template scenarios are supported with plain TypeScript.
Control flow
Conditional template with ?
<div>Random > 0.5: {Math.random() > .5 ? <strong>yes</strong> : 'no'}</div>Repeat a template with Array.map
const items = ['item', 'item2'];
<ul>
{items.map(i => <li>{i}</li>)}
</ul>;Helper templates
Want a helper template? Just call a function
function listItem(n: number) {
return <li>{n}</li>;
}
<ul>
{[1, 2].map(listItem)}
</ul>Using a helper template like an element
Want a helper component? Create a function that implements CustomElementHandler and you can call it like an HTML element.
import {Attributes, CustomElementHandler} from "typed-html"
function Button(attributes: Attributes | undefined, contents: string[]) {
return <div><button type="button" class="original-class" {...attributes}>{contents}</button></div>;
}
// Or
const Button: CustomElementHandler = (attributes, contents) => <div><button type="button" class="original-class" {...attributes}>{contents}</button></div>;
}
console.log(<Button style="color:#f00">Button Text</Button>);Prints:
<div>
<button type="button" class="original-class" style="color:#f00">Button Text</button>
</div>React-style children
It's possible to write React-style components as well. Consider the example below.
import {Attributes, CustomElementHandler} from "typed-html"
function Button({ children, ...attributes }: Attributes) {
return <div><button type="button" class="original-class" {...attributes}>{children}</button></div>;
}
console.log(<Button style="color:#f00">Button Text</Button>);Prints:
<div>
<button type="button" class="original-class" style="color:#f00">Button Text</button>
</div>Sanitization
Security is NOT a feature. This library does NOT sanitize.
const script = '<script>alert("hacked!")</script>';
const body = <body>{script}</body>;Will result in:
<body><script>alert('hacked!');</script></body>If you need sanitization, you can use something like sanitize-html.
Supported HTML
All HTML elements and attributes are supported, except for the svg.
- Supported html elements: https://dev.w3.org/html5/html-author/#the-elements
- Supported html events: http://htmlcss.wikia.com/wiki/HTML5_Event_Attributes
Missing an element or attribute? Please create an issue or a PR to add it. It's easy to add.
Void elements
Void elements (elements without closing tags) are supported, however you should close them in TypeScript.
const img = <img href="/foo/bar.png">; // => Error! JSX element 'img' has no corresponding closing tag.In the example above, closing the image tag is required for valid TSX code:
const img = <img href="/foo/bar.png"></img>; // => '<img href="https://github.com/foo/bar.png">'See this code for a list of supported void elements.
Attribute types
All HTML attributes support a string value, however some attributes also support a number, Date or boolean(or absent value) type:
<meter value={1} min={0} max={5} low={1} high={4} optimum={3}></meter>;
// => <meter value="1" min="0" max="5" low="1" high="4" optimum="3"></meter>
<ol start={3}></ol>;
<progress value={3} max={4}></progress>;
<td colspan={3} rowspan={3}></td>;
<th colspan={3} rowspan={3}></th>;
const date = new Date('1914-12-20T08:00');
<time datetime={date}></time>;
// => <time datetime="1914-12-20T08:00:00.000Z"></time>
<ins datetime={date}>updated</ins>;
<del datetime={date}>old</del>;
// => <form> <input type="checkbox" checked> </form>
<form novalidate={false}>
<input type="checkbox" checked disabled={false}></input>
</form>Custom elements
You can add custom elements by adding them to the intrinsic elements yourself:
// MyCustomElements.d.ts
declare namespace JSX {
interface CustomElement {
customAttribute?: string;
}
interface IntrinsicElements {
myCustomElement: CustomElement;
}
}Now you can use it:
// UseCustomElement.ts
import * as elements from 'typed-html';
const myElement = <myCustomElement customAttribute="customValue"></myCustomElement>
console.log(myElement);This prints:
<my-custom-element custom-attribute="customValue"></my-custom-element>Custom attributes
Custom attribute names are already supported out-of-the-box for attributes with a dash (-) in the name. For example:
<button data-menu-item="3"></button>Transformation
As a browser is case insensitive when it comes to element and attribute names, it is common practice to use kebab case for this. However <custom-element></custom-element> is not allowed in TypeScript. Therefore typed-html will transform <customElement></customElement> to <custom-element></custom-element>.
This transformation also works for custom attributes you define on a custom element yourself. For example:
<customElement aCustomAttr="value"></customElement>Becomes
<custom-element a-custom-attr="value"></custom-element>How this all works
The way this works is by using TypeScript's jsx support, but not for jsx/react interoperability. Instead, it defines the normal html tags as IntrinsicElements in the JSX namespace.
At runtime, the elements.createElement function is called for every html tag. It simply converts the given element to a string with minimal overhead.
This:
<ol start={2}>{[1, 2].map(i => <li>{i}</li>)}</ol>Compiles to:
elements.createElement("ol", { start: 2 }, [1, 2].map(function (li) {
return elements.createElement("li", null, li);
}));Which translates to:
<ol start="2">
<li>1</li>
<li>2</li>
</ol>