One function. No configuration, no globals, no I/O.

import { transform } from "polytypo";

const output = transform(input, { locale: "de" });

// mode "markdown" requires an explicit dialect; "text" and "html" ignore it
transform(input, { locale: "fr", mode: "markdown", dialect: "commonmark" });

// opt out of a single rule; the order of the rest never changes
transform(input, { locale: "en-US", rules: { dashes: false } });

try {
  transform(input, { locale: "xx" });
} catch (error) {
  error.code; // "POLYTYPO_UNKNOWN_LOCALE"
}

from polytypo import transform, PolytypoError

output = transform(input, locale="de")

# mode "markdown" requires an explicit dialect; "text" and "html" ignore it
transform(input, locale="fr", mode="markdown", dialect="commonmark")

transform(input, locale="en-US", rules={"dashes": False})

try:
    transform(input, locale="xx")
except PolytypoError as error:
    error.code  # "POLYTYPO_UNKNOWN_LOCALE"

package main

import (
    "errors"
    "fmt"

    "github.com/polytypo/polytypo-go"
)

func main() {
    out, err := polytypo.Transform(input, polytypo.Options{Locale: "de"})
    if err != nil {
        var perr *polytypo.Error
        if errors.As(err, &perr) {
            _ = perr.Code // "POLYTYPO_UNKNOWN_LOCALE"
        }
    }
    fmt.Println(out)

    // Mode "markdown" requires an explicit Dialect; "text" and "html" ignore it
    _, _ = polytypo.Transform(input, polytypo.Options{
        Locale:  "fr",
        Mode:    "markdown",
        Dialect: "commonmark",
    })
}

require "polytypo"

output = Polytypo.transform(input, locale: "de")

# mode "markdown" requires an explicit dialect; "text" and "html" ignore it
Polytypo.transform(input, locale: "fr", mode: "markdown", dialect: "commonmark")

Polytypo.transform(input, locale: "en-US", rules: { dashes: false })

begin
  Polytypo.transform(input, locale: "xx")
rescue Polytypo::Error => error
  error.code # => "POLYTYPO_UNKNOWN_LOCALE"
end

<?php
use Polytypo\Polytypo;
use Polytypo\PolytypoException;

$output = Polytypo::transform($input, ['locale' => 'de']);

// mode 'markdown' requires an explicit dialect; 'text' and 'html' ignore it
Polytypo::transform($input, ['locale' => 'fr', 'mode' => 'markdown', 'dialect' => 'commonmark']);

try {
    Polytypo::transform($input, ['locale' => 'xx']);
} catch (PolytypoException $error) {
    $error->errorCode; // 'POLYTYPO_UNKNOWN_LOCALE'
}

// e.g. a remark/unified plugin, or any step that reads .md/.mdx files
import { readFile, writeFile } from "node:fs/promises";
import { transform } from "polytypo";

const path = "content/posts/hello-world.mdx";
const source = await readFile(path, "utf8");
const dialect = path.endsWith(".mdx") ? "mdx" : "commonmark";

await writeFile(path, transform(source, { locale: "en-US", mode: "markdown", dialect }));
// transform(transform(x)) === transform(x) — safe to run on every build, not just once.

// wherever a rich-text field is persisted — a webhook handler, a save hook
import { transform } from "polytypo";

function sanitizeBody(html, locale) {
  // html parsing is recovery-based and never throws POLYTYPO_MALFORMED_INPUT — that code is
  // reachable only for markdown's mdx dialect, which embeds JavaScript. Nothing to catch here.
  return transform(html, { locale, mode: "html" });
}

// call it wherever untrusted or imported copy reaches a render — not on every keystroke
import { transform } from "polytypo";

function Byline({ text, locale }) {
  return <p>{transform(text, { locale })}</p>;
}