> ## Documentation Index
> Fetch the complete documentation index at: https://prefab.prefect.io/docs/llms.txt
> Use this file to discover all available pages before exploring further.
# Code
> Display code blocks with optional language annotation.
export const ComponentPreview = ({json, height, resizable, bare, hideJson, playground, children}) => {
const hostRef = React.useRef(null);
const handleRef = React.useRef(null);
const cardRef = React.useRef(null);
const containerRef = React.useRef(null);
const [previewWidth, setPreviewWidth] = React.useState(null);
const [isDragging, setIsDragging] = React.useState(false);
const [playgroundHref, setPlaygroundHref] = React.useState(null);
React.useEffect(function () {
if (!playground) return;
var isLocal = location.hostname === "localhost" || location.hostname === "127.0.0.1";
var path = isLocal ? "/playground" : "/docs/playground";
var url = new URL(path, window.location.href);
url.hash = "code=" + playground;
setPlaygroundHref(url.href);
}, [playground]);
var jsonStr = typeof json === "string" ? json : JSON.stringify(json, null, 2);
React.useEffect(function () {
if (cardRef.current) {
var card = cardRef.current.closest(".group");
if (card) card.classList.remove("group");
}
var host = hostRef.current;
if (!host || !json) return;
function mount() {
if (!window.__prefab || !host) return;
var dark = document.documentElement.classList.contains("dark");
handleRef.current = window.__prefab.mountPreview(host, jsonStr, {
dark: dark
});
if (bare && host.shadowRoot) {
var m = host.shadowRoot.querySelector("[data-prefab-mount]");
if (m) m.style.background = "transparent";
}
}
if (window.__prefab) {
mount();
} else {
if (!window.__prefabLoading) {
if (!window.__prefabReady) {
var s = document.createElement("script");
s.src = "/renderer.js";
document.head.appendChild(s);
}
window.__prefabLoading = new Promise(function (resolve) {
function check() {
if (window.__prefabReady) {
window.__prefabReady.then(resolve);
} else {
setTimeout(check, 10);
}
}
check();
});
}
window.__prefabLoading.then(mount);
}
var observer = new MutationObserver(function () {
var dark = document.documentElement.classList.contains("dark");
if (handleRef.current) handleRef.current.setDark(dark);
});
observer.observe(document.documentElement, {
attributes: true,
attributeFilter: ["class"]
});
return function () {
observer.disconnect();
if (handleRef.current) {
handleRef.current.unmount();
handleRef.current = null;
}
};
}, [json]);
function startResize(e) {
e.preventDefault();
var startX = e.clientX;
var startW = hostRef.current ? hostRef.current.offsetWidth : 0;
var maxW = containerRef.current ? containerRef.current.offsetWidth - 10 : startW;
setIsDragging(true);
function onMove(ev) {
var w = Math.max(260, Math.min(startW + (ev.clientX - startX), maxW));
setPreviewWidth(w);
}
function onUp() {
document.removeEventListener("mousemove", onMove);
document.removeEventListener("mouseup", onUp);
setIsDragging(false);
}
document.addEventListener("mousemove", onMove);
document.addEventListener("mouseup", onUp);
}
if (bare) {
return ;
}
if (resizable) {
return
{previewWidth &&
{previewWidth}px
}
{playgroundHref && }
{children}
;
}
return
{playgroundHref && }
{children}
;
};
Code blocks display source code or configuration with automatic syntax highlighting. Set the `language` parameter to enable language-aware highlighting for Python, JavaScript, TypeScript, SQL, Bash, JSON, HTML, CSS, YAML, and Markdown.
## Basic Usage
int:\n \"\"\"Return the Answer to the Ultimate Question\n of Life, the Universe, and Everything.\"\"\"\n return 42","language":"python"}}} playground="ZnJvbSBwcmVmYWJfdWkuY29tcG9uZW50cyBpbXBvcnQgQ29kZQoKQ29kZSgiIiIKZGVmIGFuc3dlcigpIC0-IGludDoKICAgIFwiXCJcIlJldHVybiB0aGUgQW5zd2VyIHRvIHRoZSBVbHRpbWF0ZSBRdWVzdGlvbgogICAgb2YgTGlmZSwgdGhlIFVuaXZlcnNlLCBhbmQgRXZlcnl0aGluZy5cIlwiXCIKICAgIHJldHVybiA0MgoiIiIuc3RyaXAoKSwgbGFuZ3VhZ2U9InB5dGhvbiIpCg">
```python Python icon="python" theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
from prefab_ui.components import Code
Code("""
def answer() -> int:
\"\"\"Return the Answer to the Ultimate Question
of Life, the Universe, and Everything.\"\"\"
return 42
""".strip(), language="python")
```
```json Protocol icon="brackets-curly" theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
{
"view": {
"type": "Code",
"content": "def answer() -> int:\n \"\"\"Return the Answer to the Ultimate Question\n of Life, the Universe, and Everything.\"\"\"\n return 42",
"language": "python"
}
}
```
## Multiple Languages
```python Python icon="python" theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
from prefab_ui.components import Code, Column
with Column(gap=3):
Code("pip install prefab-ui", language="bash")
Code(
"SELECT name, designation\n"
"FROM crew\n"
"WHERE ship = 'Heart of Gold';",
language="sql",
)
Code('{ "ship": "Heart of Gold", "drive": "Infinite Improbability" }', language="json")
```
```json Protocol icon="brackets-curly" theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
{
"view": {
"cssClass": "gap-3",
"type": "Column",
"children": [
{"type": "Code", "content": "pip install prefab-ui", "language": "bash"},
{
"type": "Code",
"content": "SELECT name, designation\nFROM crew\nWHERE ship = 'Heart of Gold';",
"language": "sql"
},
{
"type": "Code",
"content": "{ \"ship\": \"Heart of Gold\", \"drive\": \"Infinite Improbability\" }",
"language": "json"
}
]
}
}
```
## Dynamic Content
Code content supports [expression interpolation](/concepts/expressions), so you can display server-generated output:
```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
from prefab_ui.components import Code
from prefab_ui.rx import Rx
query_result = Rx("query_result")
Code(query_result, language="sql")
```
## API Reference
Code content. Can be passed as a positional argument.
Language for syntax highlighting. Supported: `python`, `javascript`/`js`, `typescript`/`ts`, `json`, `bash`/`sh`, `sql`, `html`, `xml`, `css`, `yaml`/`yml`, `markdown`/`md`.
Additional Tailwind CSS classes.
## Protocol Reference
```json Code theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
{
"type": "Code",
"id?": "string",
"onMount?": "any",
"content": "string (required)",
"language?": "string",
"cssClass?": "string"
}
```
For the complete protocol schema, see [Code](/protocol/code).