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// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.import { parseMediaType } from "./parse_media_type.ts";import { type DBEntry } from "./_util.ts";import { db, type KeyOfDb } from "./_db.ts";
/** * Given a media type or header value, identify the encoding charset. If the * charset cannot be determined, the function returns `undefined`. * * @example * ```ts * import { getCharset } from "https://deno.land/std@$STD_VERSION/media_types/get_charset.ts"; * * getCharset("text/plain"); // `UTF-8` * getCharset("application/foo"); // undefined * getCharset("application/news-checkgroups"); // `US-ASCII` * getCharset("application/news-checkgroups; charset=UTF-8"); // `UTF-8` * ``` */export function getCharset(type: string): string | undefined {  try {    const [mediaType, params] = parseMediaType(type);    if (params && params["charset"]) {      return params["charset"];    }    const entry = db[mediaType as KeyOfDb] as DBEntry;    if (entry && entry.charset) {      return entry.charset;    }    if (mediaType.startsWith("text/")) {      return "UTF-8";    }  } catch {    // just swallow errors, returning undefined  }  return undefined;}