Document constructor fetch option (#59)

Author: mattt

README.md

@@ -65,11 +65,12 @@ console.log(prediction.output)
 const replicate = new Replicate(options);
 ```
 
-| name                | type   | description                                                                       |
-| ------------------- | ------ | --------------------------------------------------------------------------------- |
-| `options.auth`      | string | **Required**. API access token                                                    |
-| `options.userAgent` | string | Identifier of your app. Defaults to `replicate-javascript/${packageJSON.version}` |
-| `options.baseUrl`   | string | Defaults to https://api.replicate.com/v1                                          |
+| name                | type     | description                                                                       |
+| ------------------- | -------- | --------------------------------------------------------------------------------- |
+| `options.auth`      | string   | **Required**. API access token                                                    |
+| `options.userAgent` | string   | Identifier of your app. Defaults to `replicate-javascript/${packageJSON.version}` |
+| `options.baseUrl`   | string   | Defaults to https://api.replicate.com/v1                                          |
+| `options.fetch`     | function | Fetch function to use. Defaults to `globalThis.fetch`                             |
 
 ### `replicate.models.get`
 

index.js

@@ -30,7 +30,7 @@ class Replicate {
    * @param {string} options.auth - Required. API access token
    * @param {string} options.userAgent - Identifier of your app
    * @param {string} [options.baseUrl] - Defaults to https://api.replicate.com/v1
-   * @param {Function} [options.fetch] - Defaults to native fetch
+   * @param {Function} [options.fetch] - Fetch function to use. Defaults to `globalThis.fetch`
    */
   constructor(options) {
     this.auth = options.auth;