feat(httptransport): injected fetcher

src/transports/HTTPTransport.ts

@@ -1,35 +1,46 @@
 import fetch from "isomorphic-fetch";
 import { Transport } from "./Transport";
-import { JSONRPCRequestData, getNotifications, getBatchRequests } from "../Request";
+import {
+  JSONRPCRequestData,
+  getNotifications,
+  getBatchRequests,
+} from "../Request";
 import { ERR_UNKNOWN, JSONRPCError } from "../Error";
 
-type CredentialsOption = "omit" | "same-origin" | "include"
+type CredentialsOption = "omit" | "same-origin" | "include";
 
 interface HTTPTransportOptions {
-  credentials?: CredentialsOption
-  headers?: Record<string, string>
+  credentials?: CredentialsOption;
+  headers?: Record<string, string>;
+  fetcher?: typeof fetch;
 }
 
 class HTTPTransport extends Transport {
   public uri: string;
   private readonly credentials?: CredentialsOption;
-  private readonly headers: Headers
+  private readonly headers: Headers;
+  private readonly injectedFetcher?: typeof fetch;
   constructor(uri: string, options?: HTTPTransportOptions) {
     super();
     this.uri = uri;
     this.credentials = options && options.credentials;
-    this.headers = HTTPTransport.setupHeaders(options && options.headers)
+    this.headers = HTTPTransport.setupHeaders(options && options.headers);
+    this.injectedFetcher = options?.fetcher;
   }
   public connect(): Promise<any> {
     return Promise.resolve();
   }
 
-  public async sendData(data: JSONRPCRequestData, timeout: number | null = null): Promise<any> {
+  public async sendData(
+    data: JSONRPCRequestData,
+    timeout: number | null = null
+  ): Promise<any> {
     const prom = this.transportRequestManager.addRequest(data, timeout);
     const notifications = getNotifications(data);
     const batch = getBatchRequests(data);
+    const fetcher = this.injectedFetcher || fetch;
     try {
-      const result = await fetch(this.uri, {
+      const result = await fetcher(this.uri, {
         method: "POST",
         headers: this.headers,
         body: JSON.stringify(this.parseData(data)),
@@ -50,30 +61,40 @@ class HTTPTransport extends Transport {
       }
     } catch (e) {
       const responseErr = new JSONRPCError(e.message, ERR_UNKNOWN, e);
-      this.transportRequestManager.settlePendingRequest(notifications, responseErr);
-      this.transportRequestManager.settlePendingRequest(getBatchRequests(data), responseErr);
+      this.transportRequestManager.settlePendingRequest(
+        notifications,
+        responseErr
+      );
+      this.transportRequestManager.settlePendingRequest(
+        getBatchRequests(data),
+        responseErr
+      );
       return Promise.reject(responseErr);
     }
     return prom;
   }
 
   // tslint:disable-next-line:no-empty
-  public close(): void { }
+  public close(): void {}
 
   private onlyNotifications = (data: JSONRPCRequestData) => {
     if (data instanceof Array) {
-      return data.every((datum) => datum.request.request.id === null || datum.request.request.id === undefined);
+      return data.every(
+        (datum) =>
+          datum.request.request.id === null ||
+          datum.request.request.id === undefined
+      );
     }
-    return (data.request.id === null || data.request.id === undefined);
-  }
+    return data.request.id === null || data.request.id === undefined;
+  };
 
   private static setupHeaders(headerOptions?: Record<string, string>): Headers {
-    const headers = new Headers(headerOptions)
+    const headers = new Headers(headerOptions);
     // Overwrite header options to ensure correct content type.
-    headers.set("Content-Type", "application/json")
-    return headers
+    headers.set("Content-Type", "application/json");
+    return headers;
   }
 }
 
 export default HTTPTransport;
-export {HTTPTransport, HTTPTransportOptions, CredentialsOption}
+export { HTTPTransport, HTTPTransportOptions, CredentialsOption };