1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.// This module is browser compatible.
import { isIterator, isToken, needsEncoding } from "./_util.ts";
/** Serializes the media type and the optional parameters as a media type * conforming to RFC 2045 and RFC 2616. * * The type and parameter names are written in lower-case. * * When any of the arguments results in a standard violation then the return * value will be an empty string (`""`). * * @example * ```ts * import { formatMediaType } from "https://deno.land/std@$STD_VERSION/media_types/format_media_type.ts"; * * formatMediaType("text/plain", { charset: "UTF-8" }); // "text/plain; charset=UTF-8" * ``` */export function formatMediaType(  type: string,  param?: Record<string, string> | Iterable<[string, string]>,): string {  let b = "";  const [major = "", sub] = type.split("/");  if (!sub) {    if (!isToken(type)) {      return "";    }    b += type.toLowerCase();  } else {    if (!isToken(major) || !isToken(sub)) {      return "";    }    b += `${major.toLowerCase()}/${sub.toLowerCase()}`;  }
  if (param) {    param = isIterator(param) ? Object.fromEntries(param) : param;    const attrs = Object.keys(param);    attrs.sort();
    for (const attribute of attrs) {      if (!isToken(attribute)) {        return "";      }      const value = param[attribute]!;      b += `; ${attribute.toLowerCase()}`;
      const needEnc = needsEncoding(value);      if (needEnc) {        b += "*";      }      b += "=";
      if (needEnc) {        b += `utf-8''${encodeURIComponent(value)}`;        continue;      }
      if (isToken(value)) {        b += value;        continue;      }      b += `"${value.replace(/["\\]/gi, (m) => `\\${m}`)}"`;    }  }  return b;}