Rojs is a toy reactive HTML JavaScript framework inspired by Solid.
The entry point to Rojs is the render(container, template) function; this instantiates template as HTML inside a container DOM node.
Unlike most reactive frameworks Rojs declares its HTML templates using vanilla uncompiled JavaScript.
See reference for template formats.
import {render} from './src/rojs.js';
const colours = [
'red',
'orange',
'yellow',
'green',
'blue',
'purple',
];
render(document.body, [
{ tag: 'h1', textContent: 'Colours' },
{
style: { display: 'flex' },
children: colours.map(colour => ({
style: {
backgroundColor: colour,
padding: '20px',
fontSize: '20px',
},
textContent: colour,
})),
},
]);
Rendered HTML:
<body>
<h1>Colours</h1>
<div style="display: flex;">
<div style="background-color: red; padding: 20px; font-size: 20px;">red</div>
<div style="background-color: orange; padding: 20px; font-size: 20px;">orange</div>
<div style="background-color: yellow; padding: 20px; font-size: 20px;">yellow</div>
<div style="background-color: green; padding: 20px; font-size: 20px;">green</div>
<div style="background-color: blue; padding: 20px; font-size: 20px;">blue</div>
<div style="background-color: purple; padding: 20px; font-size: 20px;">purple</div>
</div>
</body>
ObservableJsonProxy is a proxy wrapper for a JSON value. This can be used to watch for changes to the value.
render() will watch any proxies used in the template and re-render affected sections of the HTML when their value changes. This is the reactive rendering feature of Rojs.
See reference for all capabilities of the proxy object.
import {createObservableJsonProxy, isObservableJsonProxy, mutate, read, readWrite, watch, write} from './src/rojs.js';
function main() {
const textProxy = createObservableJsonProxy('Hello');
addLog(textProxy); // Log: Proxy
// read() reads the text inside a proxy.
addLog(read(textProxy)); // Log: 'Hello'
// watch() reads the value in a proxy and passes it to the callback.
// The callback is re-invoked whenever the proxy's value is updated.
watch(textProxy, text => addLog(text)); // Log: 'Hello'
// write() sets the value inside a proxy.
write(textProxy, 'Hello world'); // Log: 'Hello world'
// This logged the text in the proxy due to the watch() callback above being re-invoked.
// Render the contents of textProxy and logsProxy and include a button that updates textProxy.
render(document.body, [
p(
'Text: ',
textProxy,
{tag: 'br'},
{
tag: 'button',
events: {click(event) { readWrite(textProxy, text => text + '!'); }},
textContent: 'Add !',
},
),
p(
'Logs:',
{tag: 'pre', textContent: () => read(logsProxy).join('\n')},
),
]);
}
// Using an ObservableJsonProxy for the logs so it can be rendered reactively.
const logsProxy = createObservableJsonProxy([]);
function addLog(x) {
console.log(x);
// mutate() gives you a handle to the value inside a proxy allowing you to mutate it.
mutate(logsProxy, logs => {
logs.push(isObservableJsonProxy(x) ? 'Proxy' : x);
});
}
// You can use helper functions to make your templates more succinct.
function p(...children) {
return {tag: 'p', children};
}
main();
Rendered HTML (prior to button being pressed):
<body>
<p>
Text: Hello world<br>
<button>Add !</button>
</p>
<p>
Logs:
<pre>Proxy
Hello
Hello
Hello world</pre>
</p>
</body>
render()function render(container: Node, template: Template);
Renders template as HTML inside container. Uses of ObservableJsonProxy inside template will be reactive and automatically update the HTML on change.
type Template =
null |
Node |
string |
number |
ObservableJsonProxy |
Array<Template> |
() => Template |
HtmlRead |
Component |
ElementTemplate;
interface ElementTemplate {
tag?: string;
class?: ReadingValue<string>;
style?: ReadingValue<{
[cssProperty: string]: ReadingValue<string>;
}>;
events?: { [eventName: String]: (event: Event) => void },
shadow?: Template;
children?: Template;
[attribute: string]: ReadingValue<string>;
}
| Template type | Description | Example usage | Instantiated HTML |
| `null` | TODO | TODO | TODO |
| `Node` | TODO | TODO | TODO |
| `string | number` | TODO | TODO | TODO |
| `ObservableJsonProxy` | TODO | TODO | TODO |
| Array | TODO | TODO | TODO |
| Function | TODO | TODO | TODO |
| `HtmlRead` | TODO | TODO | TODO |
| `Component` | TODO | TODO | TODO |
| `ElementTemplate` | TODO | TODO | TODO |
TODO
See CONTRIBUTING.md for details.
Apache 2.0; see LICENSE for details.
This project is not an official Google project. It is not supported by Google and Google specifically disclaims all warranties as to its quality, merchantability, or fitness for a particular purpose.