feat(parse): support filter option for key filtering (#35)

src/index.ts

@@ -50,6 +50,10 @@ export function parse(
     }
 
     const key = str.slice(index, eqIdx).trim();
+    if (opt?.filter && !opt?.filter(key)) {
+      index = endIdx + 1;
+      continue;
+    }
 
     // only assign once
     if (undefined === obj[key]) {

src/types.ts

@@ -138,4 +138,8 @@ export interface CookieParseOptions {
    * cookie value will be returned as the cookie's value.
    */
   decode?(value: string): string;
+  /**
+   * Custom function to filter parsing specific keys.
+   */
+  filter?(key: string): boolean;
 }

test/parse.test.ts

@@ -69,5 +69,14 @@ describe("cookie.parse(str, options)", () => {
         }),
       ).toMatchObject({ foo: "bar" });
     });
+
+    it("parse filter key", () => {
+      expect(parse("a=1;b=2", {
+        filter: (key) => key === "a"
+      })).toMatchObject({ a: "1" });
+
+      expect(parse("a=1;b=2"))
+        .toMatchObject({ a: "1", b: "2" });
+    })
   });
 });