fix(node-fetch): respect set-cookies given in HeadersInit (#2079)

Author: ardatan

.changeset/curvy-insects-cheer.md

@@ -0,0 +1,5 @@
+---
+'@whatwg-node/node-fetch': patch
+---
+
+Fix the bug when `set-cookies` given is ignored in `HeadersInit`

packages/node-fetch/src/Headers.ts

@@ -11,14 +11,14 @@ export class PonyfillHeaders implements Headers {
   private _map: Map<string, string> | undefined;
   private objectNormalizedKeysOfHeadersInit: string[] = [];
   private objectOriginalKeysOfHeadersInit: string[] = [];
-  private _setCookies: string[] = [];
+  private _setCookies?: string[];
 
   constructor(private headersInit?: PonyfillHeadersInit) {}
 
   // perf: we don't need to build `this.map` for Requests, as we can access the headers directly
   private _get(key: string) {
     const normalized = key.toLowerCase();
-    if (normalized === 'set-cookie') {
+    if (normalized === 'set-cookie' && this._setCookies?.length) {
       return this._setCookies.join(', ');
     }
     // If the map is built, reuse it
@@ -32,7 +32,16 @@ export class PonyfillHeaders implements Headers {
     }
 
     if (Array.isArray(this.headersInit)) {
-      return this.headersInit.find(header => header[0].toLowerCase() === normalized)?.[1] || null;
+      const found = this.headersInit.filter(
+        ([headerKey]) => headerKey.toLowerCase() === normalized,
+      );
+      if (found.length === 0) {
+        return null;
+      }
+      if (found.length === 1) {
+        return found[0][1];
+      }
+      return found.map(([, value]) => value).join(', ');
     } else if (isHeadersLike(this.headersInit)) {
       return this.headersInit.get(normalized);
     } else {
@@ -61,21 +70,23 @@ export class PonyfillHeaders implements Headers {
   // I could do a getter here, but I'm too lazy to type `getter`.
   private getMap() {
     if (!this._map) {
+      this._setCookies = [];
       if (this.headersInit != null) {
         if (Array.isArray(this.headersInit)) {
           this._map = new Map();
-          this.headersInit.forEach(([key, value]) => {
+          for (const [key, value] of this.headersInit) {
             const normalizedKey = key.toLowerCase();
             if (normalizedKey === 'set-cookie') {
               this._setCookies.push(value);
-              return;
+              continue;
             }
-            this._map!.set(normalizedKey, value);
-          });
+            this._map.set(normalizedKey, value);
+          }
         } else if (isHeadersLike(this.headersInit)) {
           this._map = new Map();
           this.headersInit.forEach((value, key) => {
             if (key === 'set-cookie') {
+              this._setCookies ||= [];
               this._setCookies.push(value);
               return;
             }
@@ -88,6 +99,7 @@ export class PonyfillHeaders implements Headers {
             if (initValue != null) {
               const normalizedKey = initKey.toLowerCase();
               if (normalizedKey === 'set-cookie') {
+                this._setCookies ||= [];
                 this._setCookies.push(initValue);
                 continue;
               }
@@ -106,6 +118,7 @@ export class PonyfillHeaders implements Headers {
   append(name: string, value: string): void {
     const key = name.toLowerCase();
     if (key === 'set-cookie') {
+      this._setCookies ||= [];
       this._setCookies.push(value);
       return;
     }
@@ -121,12 +134,12 @@ export class PonyfillHeaders implements Headers {
       return null;
     }
 
-    return value;
+    return value.toString();
   }
 
   has(name: string): boolean {
     if (name === 'set-cookie') {
-      return this._setCookies.length > 0;
+      return !!this._setCookies?.length;
     }
     return !!this._get(name); // we might need to check if header exists and not just check if it's not nullable
   }
@@ -150,7 +163,7 @@ export class PonyfillHeaders implements Headers {
   }
 
   forEach(callback: (value: string, key: string, parent: Headers) => void): void {
-    this._setCookies.forEach(setCookie => {
+    this._setCookies?.forEach(setCookie => {
       callback(setCookie, 'set-cookie', this);
     });
     if (!this._map) {
@@ -179,7 +192,7 @@ export class PonyfillHeaders implements Headers {
   }
 
   *_keys(): IterableIterator<string> {
-    if (this._setCookies.length) {
+    if (this._setCookies?.length) {
       yield 'set-cookie';
     }
     if (!this._map) {
@@ -204,7 +217,9 @@ export class PonyfillHeaders implements Headers {
   }
 
   *_values(): IterableIterator<string> {
-    yield* this._setCookies;
+    if (this._setCookies?.length) {
+      yield* this._setCookies;
+    }
     if (!this._map) {
       if (this.headersInit) {
         if (Array.isArray(this.headersInit)) {
@@ -227,7 +242,9 @@ export class PonyfillHeaders implements Headers {
   }
 
   *_entries(): IterableIterator<[string, string]> {
-    yield* this._setCookies.map(cookie => ['set-cookie', cookie] as [string, string]);
+    if (this._setCookies?.length) {
+      yield* this._setCookies.map(cookie => ['set-cookie', cookie] as [string, string]);
+    }
     if (!this._map) {
       if (this.headersInit) {
         if (Array.isArray(this.headersInit)) {
@@ -250,7 +267,10 @@ export class PonyfillHeaders implements Headers {
   }
 
   getSetCookie() {
-    return this._setCookies;
+    if (!this._setCookies) {
+      this.getMap();
+    }
+    return this._setCookies!;
   }
 
   [Symbol.iterator](): HeadersIterator<[string, string]> {
@@ -261,7 +281,7 @@ export class PonyfillHeaders implements Headers {
     const record: Record<string, string[] | string> = {};
     this.forEach((value, key) => {
       if (key === 'set-cookie') {
-        record['set-cookie'] = this._setCookies;
+        record['set-cookie'] = this._setCookies || [];
       } else {
         record[key] = value?.includes(',') ? value.split(',').map(el => el.trim()) : value;
       }

packages/node-fetch/tests/Headers.spec.ts

@@ -61,4 +61,20 @@ describe('Headers', () => {
     headers.set('X-Header', null!);
     expect(inspect(headers)).toBe("Headers { 'x-header': null }");
   });
+  describe('Set-Cookie', () => {
+    it('handles values in the given map for get method', () => {
+      const headers = new PonyfillHeaders([
+        ['set-cookie', 'a=b'],
+        ['set-cookie', 'c=d'],
+      ]);
+      expect(headers.get('Set-Cookie')).toBe('a=b, c=d');
+    });
+    it('handles values in the given map for getSetCookie method', () => {
+      const headers = new PonyfillHeaders([
+        ['set-cookie', 'a=b'],
+        ['set-cookie', 'c=d'],
+      ]);
+      expect(headers.getSetCookie()).toEqual(['a=b', 'c=d']);
+    });
+  });
 });