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/*! * Based on https://github.com/jshttp/accepts/blob/master/index.js * Copyright(c) 2014 Jonathan Ong * Copyright(c) 2015 Douglas Christopher Wilson * Copyright(c) 2020 Henry Zhuang * MIT Licensed */
import { Negotiator, lookup } from "./deps.ts";
/** * Create a new Accepts object for the given headers. * * @param {Headers} headers * @public */export class Accepts {  private headers: Headers;  private negotiator: Negotiator;
  constructor(headers: Headers) {    this.headers = headers;    this.negotiator = new Negotiator(headers);  }
  /**   * Check if the given `type(s)` is acceptable, returning   * the best match when true, otherwise `undefined`, in which   * case you should respond with 406 "Not Acceptable".   *   * The `type` value may be a single mime type string   * such as "application/json", the extension name   * such as "json" or an array `["json", "html", "text/plain"]`. When a list   * or array is given the _best_ match, if any is returned.   *   * Examples:   *   *     // Accept: text/html   *     this.types(['html']);   *     // => ["html"]   *   *     // Accept: text/*, application/json   *     this.types(['html']);   *     // => ["html"]   *     this.types(['text/html']);   *     // => ["text/html"]   *     this.types(['json', 'text']);   *     // => ["json"]   *     this.types(['application/json']);   *     // => ["application/json"]   *   *     // Accept: text/*, application/json   *     this.types(['image/png']);   *     this.types(['png']);   *     // => []   *   *     // Accept: text/*;q=.5, application/json   *     this.types(['html', 'json']);   *     // => ["json"]   *   * @param {Array} types...   * @return {Array|String|False}   * @public   */  types(types?: string[]): string[] | string | false {    // no types, return all requested types    if (!types || types.length === 0) {      return this.negotiator.mediaTypes();    }
    // no accept header, return first given type    if (!this.headers.get("accept")) {      return types[0];    }
    const mimes = types      .map(extToMime);    const accepts = this.negotiator.mediaTypes(      (mimes.filter((t) => t && validMime(t))) as string[],    );    const first = accepts[0];    return first ? types[mimes.indexOf(first)] : false;  }
  /**   * Return accepted encodings or best fit based on `encodings`.   *   * Given `Accept-Encoding: gzip, deflate`   * an array sorted by quality is returned:   *   *     ['gzip', 'deflate']   *   * @param {Array} encodings...   * @return {Array|String|False}   * @public   */  encodings(encodings?: string[]): string[] | string | false {    // no encodings, return all requested encodings    if (!encodings || encodings.length === 0) {      return this.negotiator.encodings();    }    return this.negotiator.encodings(encodings)[0] || false;  }
  /**   * Return accepted charsets or best fit based on `charsets`.   *   * Given `Accept-Charset: utf-8, iso-8859-1;q=0.2, utf-7;q=0.5`   * an array sorted by quality is returned:   *   *     ['utf-8', 'utf-7', 'iso-8859-1']   *   * @param {Array} charsets...   * @return {Array|String|False}   * @public   */  charsets(charsets?: string[]): string[] | string | false {    // no charsets, return all requested charsets    if (!charsets || charsets.length === 0) {      return this.negotiator.charsets();    }    return this.negotiator.charsets(charsets)[0] || false;  }
  /**   * Return accepted languages or best fit based on `langs`.   *   * Given `Accept-Language: en;q=0.8, es, pt`   * an array sorted by quality is returned:   *   *     ['es', 'pt', 'en']   *   * @param {Array} langs...   * @return {Array|String|False}   * @public   */  languages(languages?: string[]): string[] | string | false {    // no languages, return all requested languages    if (!languages || languages.length === 0) {      return this.negotiator.languages();    }
    return this.negotiator.languages(languages)[0] || false;  }}
/** * Convert extnames to mime. * * @param {String} type * @return {String|undefined} * @private */
function extToMime(type: string): string | undefined {  return type.indexOf("/") === -1 ? lookup(type) : type;}
/** * Check if mime is valid. * * @param {String} type * @return {String} * @private */
function validMime(type?: string): boolean {  return typeof type === "string";}