feat: allow providing custom fetch implementation

README.md

@@ -35,6 +35,17 @@ Then you can use it from a global `supabase` variable:
 </script>
 ```
 
+### Custom `fetch` implementation
+
+`supabase-js` uses the [`cross-fetch`](https://www.npmjs.com/package/cross-fetch) library to make HTTP requests, but an alternative `fetch` implementation can be provided as an option. This is most useful in environments where `cross-fetch` is not compatible, for instance Cloudflare Workers:
+
+```js
+import { createClient } from '@supabase/supabase-js'
+
+// Provide a custom `fetch` implementation as an option
+const supabase = createClient('https://xyzcompany.supabase.co', 'public-anon-key', { fetch: fetch })
+```
+
 ## Sponsors
 
 We are building the features of Firebase using enterprise-grade, open source products. We support existing communities wherever possible, and if the products don’t exist we build them and open source them ourselves. Thanks to these sponsors who are making the OSS ecosystem better for everyone.

src/SupabaseClient.ts

@@ -1,6 +1,6 @@
 import { DEFAULT_HEADERS } from './lib/constants'
 import { stripTrailingSlash } from './lib/helpers'
-import { SupabaseClientOptions } from './lib/types'
+import { Fetch, SupabaseClientOptions } from './lib/types'
 import { SupabaseAuthClient } from './lib/SupabaseAuthClient'
 import { SupabaseQueryBuilder } from './lib/SupabaseQueryBuilder'
 import { SupabaseStorageClient } from '@supabase/storage-js'
@@ -32,6 +32,7 @@ export default class SupabaseClient {
   protected authUrl: string
   protected storageUrl: string
   protected realtime: RealtimeClient
+  protected fetch?: Fetch
 
   /**
    * Create a new client for use in the browser.
@@ -43,6 +44,7 @@ export default class SupabaseClient {
    * @param options.detectSessionInUrl Set to "true" if you want to automatically detects OAuth grants in the URL and signs in the user.
    * @param options.headers Any additional headers to send with each network request.
    * @param options.realtime Options passed along to realtime-js constructor.
+   * @param options.fetch A custom fetch implementation.
    */
   constructor(
     protected supabaseUrl: string,
@@ -64,6 +66,8 @@ export default class SupabaseClient {
     this.auth = this._initSupabaseAuthClient(settings)
     this.realtime = this._initRealtimeClient(settings.realtime)
 
+    this.fetch = settings.fetch
+
     // In the future we might allow the user to pass in a logger to receive these events.
     // this.realtime.onOpen(() => console.log('OPEN'))
     // this.realtime.onClose(() => console.log('CLOSED'))
@@ -74,7 +78,7 @@ export default class SupabaseClient {
    * Supabase Storage allows you to manage user-generated content, such as photos or videos.
    */
   get storage() {
-    return new SupabaseStorageClient(this.storageUrl, this._getAuthHeaders())
+    return new SupabaseStorageClient(this.storageUrl, this._getAuthHeaders(), this.fetch)
   }
 
   /**
@@ -89,6 +93,7 @@ export default class SupabaseClient {
       schema: this.schema,
       realtime: this.realtime,
       table,
+      fetch: this.fetch,
     })
   }
 
@@ -166,6 +171,7 @@ export default class SupabaseClient {
       persistSession,
       detectSessionInUrl,
       localStorage,
+      fetch: this.fetch,
     })
   }
 
@@ -180,6 +186,7 @@ export default class SupabaseClient {
     return new PostgrestClient(this.restUrl, {
       headers: this._getAuthHeaders(),
       schema: this.schema,
+      fetch: this.fetch,
     })
   }
 

src/lib/SupabaseQueryBuilder.ts

@@ -1,7 +1,7 @@
 import { PostgrestQueryBuilder } from '@supabase/postgrest-js'
 import { SupabaseRealtimeClient } from './SupabaseRealtimeClient'
 import { RealtimeClient } from '@supabase/realtime-js'
-import { SupabaseEventTypes, SupabaseRealtimePayload } from './types'
+import { Fetch, SupabaseEventTypes, SupabaseRealtimePayload } from './types'
 
 export class SupabaseQueryBuilder<T> extends PostgrestQueryBuilder<T> {
   private _subscription: SupabaseRealtimeClient
@@ -14,14 +14,16 @@ export class SupabaseQueryBuilder<T> extends PostgrestQueryBuilder<T> {
       schema,
       realtime,
       table,
+      fetch,
     }: {
       headers?: { [key: string]: string }
       schema: string
       realtime: RealtimeClient
       table: string
+      fetch?: Fetch
     }
   ) {
-    super(url, { headers, schema })
+    super(url, { headers, schema, fetch })
 
     this._subscription = new SupabaseRealtimeClient(realtime, headers, schema, table)
     this._realtime = realtime

src/lib/types.ts

@@ -1,6 +1,8 @@
 import { GoTrueClient } from '@supabase/gotrue-js'
 import { RealtimeClientOptions } from '@supabase/realtime-js'
 
+export type Fetch = typeof fetch
+
 type GoTrueClientOptions = ConstructorParameters<typeof GoTrueClient>[0]
 
 export interface SupabaseAuthClientOptions extends GoTrueClientOptions {}
@@ -35,6 +37,11 @@ export type SupabaseClientOptions = {
    * Options passed to the realtime-js instance
    */
   realtime?: RealtimeClientOptions
+
+  /**
+   * A custom `fetch` implementation.
+   */
+  fetch?: Fetch
 }
 
 export type SupabaseRealtimePayload<T> = {