Code

Info:Content

A read-only, syntax-highlighted code block themed entirely from the code-token family.

code block

syntax highlight

snippet

pre

monospace

highlighting

type Theme = { bg: string; accent: string };

const derive = (theme: Theme): string =>
	`--bg-0: ${theme.bg}; --accent: ${theme.accent};`;

console.log(derive({ bg: "#0f1115", accent: "#5b8cff" }));

fn main() {
	let accent = "#5b8cff";
	println!("derive from {accent}");
}

.xtyle-code {
	color: var(--code-fg);
	background: var(--code-bg);
}

1function total(items) {2	let sum = 0;3	for (const n of items) sum += n;4	return sum;5}

const message = "a deliberately long single line that would otherwise scroll sideways, but soft-wraps instead so the whole statement stays readable in a narrow column";

theme.ts

type Theme = { bg: string; accent: string };

const derive = (theme: Theme): string =>
	`--bg-0: ${theme.bg}; --accent: ${theme.accent};`;

console.log(derive({ bg: "#0f1115", accent: "#5b8cff" }));

Code is a turnkey, read-only code block with the tokenizer built in; it's the first component to read the --code-* family. It tokenizes with Prism, whose output is class-based, so the block re-themes live the moment the theme changes: the colors are just cascading CSS variables, never baked inline.

The lang prop names the language with aliases resolved (ts → typescript), and the source is the element's text content (or, for Astro, a code prop). Grammar loading is fully lazy and per-language. A page with no code block loads nothing; a page with a few languages loads Prism core once plus only those grammar chunks, walking each grammar's dependencies first. At runtime the block paints immediately as plain-but-themed text and recolors in place once the grammar resolves, so there is no flash and no layout shift; the Astro binding tokenizes at build and ships pre-colored with zero browser JS. preload warms a block's grammar eagerly to kill even the minor recolor flash, sharing one warm path with the page-level XtyleCode.warm() static. An unknown language falls back to plain-but-themed text rather than erroring.

When to use

How this component composes with the rest of the set.

Set lang to the source's language; use an alias (ts, html, js) and it resolves to the canonical grammar.

On a code-heavy page, call XtyleCode.warm(["ts", "rust"]) once at startup, or mark individual blocks preload, to load grammars before first paint.

For a language Prism does not ship, register it with XtyleCode.registerLanguage(name, grammar) and use that name as lang.

Reach for the Astro binding when the code is known at build time; it ships pre-colored with zero grammar bytes in the browser.

Props

8 props, straight from the manifest.

Prop	Type	Default	Bindings	Description
lang html: language	string	—	html svelte astro	The language id, with aliases resolved (`ts` → `typescript`). An unknown id falls back to plain-but-themed text. In markup the attribute is `language`; `lang` is the HTML global and means a natural language, not a programming one.
code	string	—	html svelte astro	The source to highlight. Optional for html/svelte (the text content is used); the canonical input for Astro's build-time tokenization.
preload	boolean	false	html svelte astro	Warm this block's grammar eagerly and emit a `modulepreload` hint, killing the minor recolor flash on known code-heavy pages.
copy	boolean	true	html svelte astro	The copy-to-clipboard button. On by default; set `copy="false"` (or `copy="none"`) to drop it. It only paints where it can work: hidden in an insecure context (no Clipboard API) and on the zero-JS Astro path.
wrap	boolean	false	html svelte astro	Soft-wrap long lines instead of scrolling them horizontally. Purely declarative; the host attribute drives a CSS rule, so it needs no JavaScript and works on the zero-JS Astro path.
lineNumbers html: line-numbers	boolean	false	html svelte astro	Number each line in a gutter that stays put while the code scrolls sideways. Tag-aware, so a token spanning lines (a block comment, a multi-line string) still numbers cleanly, and it co-operates with `wrap` (a wrapped line keeps a single number at its top). The gutter is pure derived chrome; it borrows `--code-comment` and `--field-border`, adding no tokens, and renders on the zero-JS Astro path too.
highlight	string	—	html svelte astro	Tint chosen lines with `--code-line-highlight` to call out the ones that matter: a 1-based spec like `2`, `2,4`, or `4-6`, mixable as `1,3-5,8`. Pairs with `line-numbers`, works under `wrap`, and renders on the zero-JS Astro path; it reuses a token the algorithm already derives, so it adds none.
caption	string	—	html svelte astro	A caption header above the block, typically a filename. Left empty, no header renders. It rounds the block's top corners into the strip and reads in the mono face; it reuses chrome tokens, so it adds none, and renders on the zero-JS Astro path.

Appearance

States

scroll-focus

.xtyle-code:focus-visible

Keyboard focus on a block wide enough to scroll horizontally, which turns tabbable only when it overflows: an outline sitting outside the border box, so the scrolled code can't cover it.

Anatomy

The named parts that make up the component. Created from script it renders a shadow root, where a ::part() handle is reachable from your own stylesheet and the class beside it is internal. Upgraded over server-rendered markup it renders light DOM, where the class is the handle.

pre

Success:::part(pre)

.xtyle-code

The block surface: the scroll container that carries the code background and padding.

--code-bg

--code-fg

--radius-md

--font-mono

--text-sm

--space-4

code

Success:::part(code)

.xtyle-code code

The tokenized source: .token.* spans colored by the per-scope code tokens.

--code-keyword

--code-string

--code-comment

--code-function

caption

Success:::part(caption)

.xtyle-code-caption

An optional header strip above the block, set via caption (a filename, say); reads in the mono face on a neutral surface and rounds the block's top corners into it.

--neutral-bg

--neutral-text

--field-border

--radius-md

--font-mono

--text-xs

copy

Success:::part(copy)

.xtyle-code-copy

The copy-to-clipboard button, anchored top-right; fades in on hover or focus and flashes a vivid Copied state on success.

--neutral-bg

--field-border

--radius-sm

--success-vivid

line

internal

.xtyle-code-line

A single logical line of source, wrapped as a row when line-numbers or highlight is set.

line-number

internal

.xtyle-code-line__number

The per-line gutter cell, shown when line-numbers is set; it sticks to the left edge as the code scrolls sideways and reads dimmed, like a comment. It is a real node the fragment draws, one per row, so a mod can restyle it, move it to the trailing edge, or grow a fold column beside it.

--code-comment

--field-border

--code-bg

--space-4

--space-2

line-highlight

internal

.xtyle-code-line[data-line-highlight]

A line called out by highlight; the whole row is tinted with --code-line-highlight, the low-alpha accent the algorithm derives for exactly this.

--code-line-highlight

Tokens & coverage

What the component consumes, checked live against what the algorithm produces.

Success:fully covered

38/38 consumed tokens produced

default register: 311 tokens

Live coverage check against the xtyle-default register (derive(xtyleDefault, { anchors }) → coverComponent(manifest, register)). Every token this component consumes must be a key the algorithm produces.

--border-thick

--border-thin

--code-attr

--code-bg

--code-comment

--code-fg

--code-function

--code-keyword

--code-line-highlight

--code-number

--code-operator

--code-punctuation

--code-regexp

--code-selection

--code-string

--code-tag

--code-type

--code-variable

--duration-fast

--ease-standard

--field-border

--font-mono

--font-sans

--leading-normal

--neutral

--neutral-bg

--neutral-fg

--neutral-text

--radius-md

--radius-sm

--ring

--space-1

--space-2

--space-4

--success

--success-vivid

--text-sm

--text-xs

Slots

default

html

svelte

The source code as text content (html/svelte). For Astro, pass the source via the code prop instead.

Code

Languages and preload

A TypeScript block and a preloaded Rust block, both colored from the code-token family.

<xtyle-code lang="ts">const greet = (name: string) =&gt; `hi ${name}`;</xtyle-code>

<xtyle-code lang="rust" preload>fn main() { println!("hello"); }</xtyle-code>

<script lang="ts">
	import { Code } from "@xtyle/svelte";
</script>

<Code lang="ts">{`const greet = (name: string) => \`hi ${name}\`;`}</Code>

---
import Code from "@xtyle/astro/Code.astro";
---

<Code lang="ts" code={`const greet = (name: string) => \`hi ${name}\`;`} />

Soft-wrap long lines

wrap folds long lines into the column instead of scrolling them sideways. It's a declarative host attribute, so it needs no JavaScript and works on the static Astro path.

<xtyle-code lang="ts" wrap>const message = "a long line that soft-wraps in a narrow column instead of scrolling sideways";</xtyle-code>

<script lang="ts">
	import { Code } from "@xtyle/svelte";
</script>

<Code lang="ts" wrap>{`const message = "a long line that soft-wraps instead of scrolling";`}</Code>

---
import Code from "@xtyle/astro/Code.astro";
---

<Code lang="ts" wrap code={`const message = "a long line that soft-wraps instead of scrolling";`} />

Line numbers

line-numbers adds a counter gutter that sticks to the left edge as the code scrolls and keeps a single number per logical line even under wrap.

<xtyle-code lang="ts" line-numbers>function add(a: number, b: number) {
	return a + b;
}

const sum = add(2, 3);</xtyle-code>

<script lang="ts">
	import { Code } from "@xtyle/svelte";
</script>

<Code lang="ts" lineNumbers>{`function add(a, b) {
	return a + b;
}`}</Code>

---
import Code from "@xtyle/astro/Code.astro";
---

<Code lang="ts" lineNumbers code={`function add(a, b) {
	return a + b;
}`} />

Highlighting lines

highlight tints the lines that matter, via a 1-based spec like 2,4 or 4-6, drawn from the --code-line-highlight token the algorithm already derives; it pairs with line-numbers.

<xtyle-code lang="ts" line-numbers highlight="2,4">function total(items) {
	let sum = 0;
	for (const n of items) sum += n;
	return sum;
}</xtyle-code>

<script lang="ts">
	import { Code } from "@xtyle/svelte";
</script>

<Code lang="ts" lineNumbers highlight="2,4">{`function total(items) {
	let sum = 0;
	for (const n of items) sum += n;
	return sum;
}`}</Code>

---
import Code from "@xtyle/astro/Code.astro";
---

<Code lang="ts" lineNumbers highlight="2,4" code={`function total(items) {
	let sum = 0;
	for (const n of items) sum += n;
	return sum;
}`} />

A caption header

caption adds a header strip above the block for a filename or label, rounding the top corners into it. It reuses chrome tokens and renders on the static Astro path.

<xtyle-code lang="ts" caption="theme.ts">export const accent = "#5b8cff";</xtyle-code>

<script lang="ts">
	import { Code } from "@xtyle/svelte";
</script>

<Code lang="ts" caption="theme.ts">{`export const accent = "#5b8cff";`}</Code>

---
import Code from "@xtyle/astro/Code.astro";
---

<Code lang="ts" caption="theme.ts" code={`export const accent = "#5b8cff";`} />

Languages

Every language the code block can highlight, 299 in all; each grammar lazy-loaded per block. An unknown language renders as plain, themed text rather than erroring.

Added by xtyle

Info:astro

Info:svelte

Prism ships neither; xtyle adds them. Everything else is Prism's canonical set.

Aliases

adoc → asciidoc

arm-asm → armasm

art → arturo

atom → markup

avdl → avro-idl

avs → avisynth

cfc → cfscript

cilk → cilkcpp

All 299 languages

abapabnfactionscriptadaagdaalantlr4apacheconfapexaplapplescriptaqlarduinoarffarmasmarturoasciidocasm6502asmatmelaspnetastroautohotkeyautoitavisynthavro-idlawkbashbasicbatchbbcodebbjbicepbirbbisonbnfbqnbrainfuckbrightscriptbrobslccfscriptchaiscriptcilcilkccilkcppclikeclojurecmakecobolcoffeescriptconcurnascooklangcoqcppcrystalcsharpcshtmlcspcsscss-extrascsvcuecypherddartdataweavedaxdhalldiffdjangodns-zone-filedockerdotebnfeditorconfigeiffelejselixirelmerberlangetluaexcel-formulafactorfalsefirestore-security-rulesflowfortranfsharpftlgapgcodegdscriptgedcomgettextgherkingitglslgmlgngogo-modulegradlegraphqlgroovyhamlhandlebarshaskellhaxehclhlslhoonhpkphstshttpichigojamiconicu-message-formatidrisiecstignoreinform7iniiojjavajavadocjavadoclikejavascriptjavastacktracejexljoliejqjs-extrasjs-templatesjsdocjsonjson5jsonpjsstacktracejsxjuliakeepalivedkeymankotlinkumirkustolatexlattelesslilypondlinker-scriptliquidlisplivescriptllvmloglolcodeluamagmamakefilemarkdownmarkupmarkup-templatingmatamatlabmaxscriptmelmermaidmetafontmizarmongodbmonkeymoonscriptn1qln4jsnand2tetris-hdlnaniscriptnasmneonnevodnginxnimnixnsisobjectivecocamlodinopenclopenqasmozparigpparserpascalpascaligopcaxispeoplecodeperlphpphp-extrasphpdocplant-umlplsqlpowerquerypowershellprocessingprologpromqlpropertiesprotobufpslpugpuppetpurepurebasicpurescriptpythonqqmlqoreqsharprracketreasonregexregorenpyrescriptrestriproboconfrobotframeworkrubyrustsassassscalaschemescssshell-sessionsmalismalltalksmartysmlsoliditysolution-filesoysparqlsplunk-splsqfsqlsquirrelstanstatastylussupercollidersvelteswiftsystemdt4-cst4-templatingt4-vbtaptcltextiletomltremortsxtt2turtletwigtypescripttyposcriptunrealscriptuorazorurivvalavbnetvelocityverilogvhdlvimvisual-basicwarpscriptwasmweb-idlwgslwikiwolframwrenxeoraxml-docxojoxqueryyamlyangzig

Code

Themed highlighting, three languages

Line numbers & highlights

Soft-wrap

Caption header

When to use

Props

Appearance

States

Anatomy

Tokens & coverage

Slots

Code

Languages and preload

Soft-wrap long lines

Line numbers

Highlighting lines

A caption header

Languages

Related

Code

Live demo

Themed highlighting, three languages

Line numbers & highlights

Soft-wrap

Caption header

When to use

Props

Appearance

States

Anatomy

Tokens & coverage

Slots

Accessibility

Code

Languages and preload

Soft-wrap long lines

Line numbers

Highlighting lines

A caption header

Languages

Related