feat(list): add parser for list-based fields

Author: TomokiMiyauci

README.md

@@ -542,6 +542,34 @@ assert(response.headers.get(header), value);
 assert(init !== response);
 ```
 
+## Lists
+
+Compliant with
+[RFC 9110, 5.6.1. Lists](https://www.rfc-editor.org/rfc/rfc9110.html#section-5.6.1).
+
+### parseListFields
+
+Parse
+[list-based fields](https://www.rfc-editor.org/rfc/rfc9110.html#section-5.5-7)
+into array.
+
+Strings enclosed in double quotes are safely handled.
+
+```ts
+import { parseListFields } from "https://deno.land/x/http_utils@$VERSION/list.ts";
+import { assert } from "https://deno.land/std@$VERSION/testing/asserts.ts";
+
+assert(parseListFields("foo , ,bar,charlie"), [
+  "foo",
+  "bar",
+  "charlie",
+]);
+assert(parseListFields(`"Sat, 04 May 1996", "Wed, 14 Sep 2005"`), [
+  `"Sat, 04 May 1996"`,
+  `"Wed, 14 Sep 2005"`,
+]);
+```
+
 ## Tokens
 
 Compliant with

_tools/meta.ts

@@ -107,5 +107,10 @@ export const makeOptions = (version: string): BuildOptions => ({
       version: "1.1.1",
       subPath: "is_null",
     },
+    "https://deno.land/x/[email protected]/trim.ts": {
+      name: "@miyauci/prelude",
+      version: "1.2.0",
+      subPath: "trim.js",
+    },
   },
 });

deno.lock

@@ -2,3 +2,4 @@
 // This module is browser compatible.
 
 export { isNull } from "https://deno.land/x/[email protected]/is_null.ts";
+export { trim } from "https://deno.land/x/[email protected]/trim.ts";

deps.ts

@@ -0,0 +1,30 @@
+// Copyright 2023-latest the httpland authors. All rights reserved. MIT license.
+// This module is browser compatible.
+
+import { trim } from "./deps.ts";
+
+/** Parse [list-based fields](https://www.rfc-editor.org/rfc/rfc9110.html#section-5.5-7) into array.
+ * Strings enclosed in double quotes are safely handled.
+ *
+ * @example
+ * ```ts
+ * import { parseListFields } from "https://deno.land/x/http_utils@$VERSION/list.ts";
+ * import { assert } from "https://deno.land/std@$VERSION/testing/asserts.ts";
+ *
+ * assert(parseListFields("foo , ,bar,charlie"), [
+ *   "foo",
+ *   "bar",
+ *   "charlie",
+ * ]);
+ * assert(parseListFields(`"Sat, 04 May 1996", "Wed, 14 Sep 2005"`), [
+ *   `"Sat, 04 May 1996"`,
+ *   `"Wed, 14 Sep 2005"`,
+ * ]);
+ * ```
+ */
+export function parseListFields(input: string): string[] {
+  return input
+    .split(/,(?=(?:(?:[^"]*?"){2})*?[^"]*?$)/)
+    .map(trim)
+    .filter(Boolean);
+}

list.ts

@@ -0,0 +1,56 @@
+import { parseListFields } from "./list.ts";
+import { assertEquals, describe, it } from "./_dev_deps.ts";
+
+describe("parseListFields", () => {
+  it("should ", () => {
+    const table: [string, string[]][] = [
+      ["", []],
+      ["a", ["a"]],
+      ["a, b, c", ["a", "b", "c"]],
+      ["   a, a   , a   ", ["a", "a", "a"]],
+      [`"", `, [`""`]],
+      [`","`, [`","`]],
+      [`",", `, [`","`]],
+      [`"," ,`, [`","`]],
+      [`",,," ,`, [`",,,"`]],
+      [`"," , " , "`, [`","`, `" , "`]],
+      [`","abc,`, [`","abc`]],
+      ["a, b,,,,", ["a", "b"]],
+      ["a, b, c", ["a", "b", "c"]],
+      ["a,b,c", ["a", "b", "c"]],
+      ["a,,c", ["a", "c"]],
+      [",,,", []],
+      [`"a,b"`, [`"a,b"`]],
+      [`"a,b",c, "d,e", f f , g `, [`"a,b"`, "c", `"d,e"`, "f f", "g"]],
+      [`   complex,pattern,"abc", "abc , def", ,,,, """, , ",""`, [
+        "complex",
+        "pattern",
+        `"abc"`,
+        `"abc , def"`,
+        `""", , "`,
+        `""`,
+      ]],
+      [`",","`, [`"`, `","`]],
+      [`",",","`, [`","`, `","`]],
+      [`",",",",`, [`","`, `","`]],
+      [`",",",","`, [`"`, `","`, `","`]],
+      [`",",",",",`, [`"`, `","`, `","`]],
+      [`",",",",","`, [`","`, `","`, `","`]],
+      [`"`, [`"`]],
+      [`""`, [`""`]],
+      [`"""`, [`"""`]],
+      [`""""`, [`""""`]],
+      [`"",""`, [`""`, `""`]],
+      [`",",`, [`","`]],
+      [`"abc,def", "efg, hij", "lmn, opq"`, [
+        '"abc,def"',
+        '"efg, hij"',
+        '"lmn, opq"',
+      ]],
+    ];
+
+    table.forEach(([input, expected]) => {
+      assertEquals(parseListFields(input), expected);
+    });
+  });
+});