feat(token): add http token utilities

Author: TomokiMiyauci

README.md

@@ -542,6 +542,46 @@ assert(response.headers.get(header), value);
 assert(init !== response);
 ```
 
+## Tokens
+
+Compliant with
+[RFC 9110, 5.6.2. Tokens](https://www.rfc-editor.org/rfc/rfc9110.html#section-5.6.2).
+
+### isTchar
+
+Whether the input is
+[tchar](https://www.rfc-editor.org/rfc/rfc9110.html#section-5.6.2-2) or not.
+
+```ts
+import { isTchar } from "https://deno.land/x/http_utils@$VERSION/token.ts";
+import {
+  assert,
+  assertFalse,
+} from "https://deno.land/std@$VERSION/testing/asserts.ts";
+
+assert(isTchar("!"));
+assert(isTchar("a"));
+assert(isTchar("Z"));
+assertFalse(isTchar(""));
+```
+
+### isToken
+
+Whether the input is
+[token](https://www.rfc-editor.org/rfc/rfc9110.html#section-5.6.2-2) or not.
+
+```ts
+import { isToken } from "https://deno.land/x/http_utils@$VERSION/token.ts";
+import {
+  assert,
+  assertFalse,
+} from "https://deno.land/std@$VERSION/testing/asserts.ts";
+
+assert(isToken("token"));
+assert(isTchar("*!~"));
+assertFalse(isToken(""));
+```
+
 ## License
 
 Copyright © 2023-present [httpland](https://github.com/httpland).

token.ts

@@ -0,0 +1,114 @@
+// Copyright 2023-latest the httpland authors. All rights reserved. MIT license.
+// This module is browser compatible.
+
+type _Digit = 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9;
+type UppercaseLetter =
+  | "A"
+  | "B"
+  | "C"
+  | "D"
+  | "E"
+  | "F"
+  | "G"
+  | "H"
+  | "I"
+  | "J"
+  | "K"
+  | "L"
+  | "M"
+  | "N"
+  | "O"
+  | "P"
+  | "Q"
+  | "R"
+  | "S"
+  | "T"
+  | "U"
+  | "V"
+  | "W"
+  | "X"
+  | "Y"
+  | "Z";
+type LowercaseLetter = Lowercase<UppercaseLetter>;
+
+/** Alphabet letter. */
+export type Alpha = UppercaseLetter | LowercaseLetter;
+
+/** Digit letter. */
+export type Digit = `${_Digit}`;
+
+/** [tchar](https://www.rfc-editor.org/rfc/rfc9110.html#section-5.6.2-2) letter. */
+export type Tchar =
+  | "!"
+  | "#"
+  | "$"
+  | "%"
+  | "&"
+  | "'"
+  | "*"
+  | "+"
+  | "-"
+  | "."
+  | "^"
+  | "_"
+  | "`"
+  | "|"
+  | "~"
+  | Digit
+  | Alpha;
+
+/**
+ * ```abnf
+ * token = 1*tchar
+ * ```
+ */
+const reToken = /^[\w!#$%&'*+.^`|~-]+$/;
+
+/** Whether the input is [token](https://www.rfc-editor.org/rfc/rfc9110.html#section-5.6.2-2) or not.
+ *
+ * @example
+ * ```ts
+ * import { isToken } from "https://deno.land/x/http_utils@$VERSION/token.ts";
+ * import {
+ *   assert,
+ *   assertFalse,
+ * } from "https://deno.land/std@$VERSION/testing/asserts.ts";
+ *
+ * assert(isToken("token"));
+ * assert(isTchar("*!~"));
+ * assertFalse(isToken(""));
+ * ```
+ */
+export function isToken(input: string): boolean {
+  return reToken.test(input);
+}
+
+/**
+ * ```abnf
+ * tchar = "!" / "#" / "$" / "%" / "&" / "'" / "*"
+ *          / "+" / "-" / "." / "^" / "_" / "`" / "|" / "~"
+ *          / DIGIT / ALPHA
+ *          ; any VCHAR, except delimiters
+ * ```
+ */
+const reTchar = /^[\w!#$%&'*+.^`|~-]$/;
+
+/** Whether the input is [tchar](https://www.rfc-editor.org/rfc/rfc9110.html#section-5.6.2-2) or not.
+ *
+ * @example
+ * ```ts
+ * import { isTchar } from "https://deno.land/x/http_utils@$VERSION/token.ts";
+ * import {
+ *   assert,
+ *   assertFalse,
+ * } from "https://deno.land/std@$VERSION/testing/asserts.ts";
+ *
+ * assert(isTchar("!"));
+ * assert(isTchar("a"));
+ * assert(isTchar("Z"));
+ * assertFalse(isTchar(""));
+ * ```
+ */
+export function isTchar(input: string): input is Tchar {
+  return reTchar.test(input);
+}

token_test.ts

@@ -0,0 +1,141 @@
+import { isTchar, isToken } from "./token.ts";
+import { assert, assertFalse, describe, it } from "./_dev_deps.ts";
+
+const table: string[] = [
+  "!",
+  "#",
+  "$",
+  "%",
+  "&",
+  "'",
+  "*",
+  "+",
+  "-",
+  ".",
+  "^",
+  "_",
+  "`",
+  "|",
+  "~",
+  "0",
+  "1",
+  "2",
+  "3",
+  "4",
+  "5",
+  "6",
+  "7",
+  "8",
+  "9",
+  "A",
+  "B",
+  "C",
+  "D",
+  "E",
+  "F",
+  "G",
+  "H",
+  "I",
+  "J",
+  "K",
+  "L",
+  "M",
+  "N",
+  "O",
+  "P",
+  "Q",
+  "R",
+  "S",
+  "T",
+  "U",
+  "V",
+  "W",
+  "X",
+  "Y",
+  "Z",
+  "a",
+  "b",
+  "c",
+  "d",
+  "e",
+  "f",
+  "g",
+  "h",
+  "i",
+  "j",
+  "k",
+  "l",
+  "m",
+  "n",
+  "o",
+  "p",
+  "q",
+  "r",
+  "s",
+  "t",
+  "u",
+  "v",
+  "w",
+  "x",
+  "y",
+  "z",
+];
+
+describe("isTchar", () => {
+  it("should return true", () => {
+    table.forEach((input) => {
+      assert(isTchar(input));
+    });
+  });
+
+  it("should return false", () => {
+    const table: string[] = [
+      "",
+      "\x00",
+      " ",
+      `"`,
+      "aa",
+      "AA",
+      "あ",
+    ];
+
+    table.forEach((input) => {
+      assertFalse(isTchar(input));
+    });
+  });
+});
+
+describe("isToken", () => {
+  it("should be tchar", () => {
+    table.forEach((input) => {
+      assert(isToken(input));
+    });
+  });
+
+  it("should return true", () => {
+    const table: string[] = [
+      "aa",
+      "abcdefghijklmnopqrstuvwxyz",
+      "!#$%&'*+.^`|~-",
+      "0123456789",
+    ];
+
+    table.forEach((input) => {
+      assert(isToken(input));
+    });
+  });
+
+  it("should return false", () => {
+    const table: string[] = [
+      "",
+      "\x00",
+      " ",
+      `"`,
+      "あ",
+    ];
+
+    table.forEach((input) => {
+      assertFalse(isToken(input));
+    });
+  });
+});