Make Astro.cookies.get(key) return undefined (#7888)

.changeset/twenty-cheetahs-deny.md

@@ -0,0 +1,17 @@
+---
+'astro': major
+---
+
+Astro.cookies.get(key) returns undefined if cookie doesn't exist
+
+With this change, Astro.cookies.get(key) no longer always returns a `AstroCookie` object. Instead it now returns `undefined` if the cookie does not exist.
+
+You should update your code if you assume that all calls to `get()` return a value. When using with `has()` you still need to assert the value, like so:
+
+```astro
+---
+if(Astro.cookies.has(id)) {
+  const id = Astro.cookies.get(id)!;
+}
+---
+```

packages/astro/src/core/cookies/cookies.ts

@@ -15,14 +15,14 @@ interface AstroCookieSetOptions {
 type AstroCookieDeleteOptions = Pick<AstroCookieSetOptions, 'domain' | 'path'>;
 
 interface AstroCookieInterface {
-	value: string | undefined;
+	value: string;
 	json(): Record<string, any>;
 	number(): number;
 	boolean(): boolean;
 }
 
 interface AstroCookiesInterface {
-	get(key: string): AstroCookieInterface;
+	get(key: string): AstroCookieInterface | undefined;
 	has(key: string): boolean;
 	set(
 		key: string,
@@ -37,7 +37,7 @@ const DELETED_VALUE = 'deleted';
 const responseSentSymbol = Symbol.for('astro.responseSent');
 
 class AstroCookie implements AstroCookieInterface {
-	constructor(public value: string | undefined) {}
+	constructor(public value: string) {}
 	json() {
 		if (this.value === undefined) {
 			throw new Error(`Cannot convert undefined to an object.`);
@@ -97,20 +97,23 @@ class AstroCookies implements AstroCookiesInterface {
 	 * @param key The cookie to get.
 	 * @returns An object containing the cookie value as well as convenience methods for converting its value.
 	 */
-	get(key: string): AstroCookie {
+	get(key: string): AstroCookie | undefined {
 		// Check for outgoing Set-Cookie values first
 		if (this.#outgoing?.has(key)) {
 			let [serializedValue, , isSetValue] = this.#outgoing.get(key)!;
 			if (isSetValue) {
 				return new AstroCookie(serializedValue);
 			} else {
-				return new AstroCookie(undefined);
+				return undefined;
 			}
 		}
 
 		const values = this.#ensureParsed();
-		const value = values[key];
-		return new AstroCookie(value);
+		if(key in values) {
+			const value = values[key];
+			return new AstroCookie(value);
+		}
+
 	}
 
 	/**

packages/astro/test/units/cookies/delete.test.js

@@ -30,7 +30,7 @@ describe('astro/src/core/cookies', () => {
 			expect(cookies.get('foo').value).to.equal('bar');
 
 			cookies.delete('foo');
-			expect(cookies.get('foo').value).to.equal(undefined);
+			expect(cookies.get('foo')).to.equal(undefined);
 		});
 
 		it('calling cookies.has() after returns false', () => {

packages/astro/test/units/cookies/get.test.js

@@ -16,6 +16,13 @@ describe('astro/src/core/cookies', () => {
 			expect(cookies.get('foo').value).to.equal('bar');
 		});
 
+		it('Returns undefined is the value doesn\'t exist', () => {
+			const req = new Request('http://example.com/');
+			let cookies = new AstroCookies(req);
+			let cookie = cookies.get('foo');
+			expect(cookie).to.equal(undefined);
+		});
+
 		describe('.json()', () => {
 			it('returns a JavaScript object', () => {
 				const req = new Request('http://example.com/', {
@@ -29,13 +36,6 @@ describe('astro/src/core/cookies', () => {
 				expect(json).to.be.an('object');
 				expect(json.key).to.equal('value');
 			});
-
-			it('throws if the value is undefined', () => {
-				const req = new Request('http://example.com/');
-				let cookies = new AstroCookies(req);
-				let cookie = cookies.get('foo');
-				expect(() => cookie.json()).to.throw('Cannot convert undefined to an object.');
-			});
 		});
 
 		describe('.number()', () => {