fix(:mag:): allow node.js clients to access streams

AFFECTS PACKAGES:
@esri/arcgis-rest-request

ISSUES CLOSED: #373

.gitignore

@@ -84,6 +84,7 @@ packages/arcgis-rest-portal/
 
 #
 test.html
+test.js
 
 #
 demos/test/*

packages/arcgis-rest-request/src/request.ts

@@ -271,16 +271,16 @@ export function request(
           return response.text();
         case "text":
           return response.text();
-        /* istanbul ignore next blob responses are difficult to make cross platform we will just have to trust the isomorphic fetch will do its job */
+        /* istanbul ignore next blob responses are difficult to make cross platform we will just have to trust that isomorphic fetch will do its job */
         case "image":
-          return response.blob();
+          return polymorphicBlob(response);
         /* istanbul ignore next */
         case "zip":
-          return response.blob();
+          return polymorphicBlob(response);
         /* istanbul ignore next */
         default:
           // hopefully we never need to handle JSON payloads when no f= parameter is set
-          return response.blob();
+          return polymorphicBlob(response);
       }
     })
     .then(data => {
@@ -291,3 +291,20 @@ export function request(
       }
     });
 }
+
+function polymorphicBlob(response: any) {
+  /* istanbul ignore else
+    fetch in the browser includes support for response.blob()
+  */
+  if (typeof window !== "undefined") {
+    return response.blob();
+  } else {
+  /*
+    node-fetch recommends streaming response.body instead
+    https://github.com/bitinn/node-fetch/issues/78
+
+    karma coverage only measures browser tests
+  */
+    return response;
+  }
+}

packages/arcgis-rest-request/test/request.test.ts

@@ -11,6 +11,17 @@ import { ArcGISOnlineError } from "./mocks/errors";
 import { WebMapAsText, WebMapAsJSON } from "./mocks/webmap";
 import { GeoJSONFeatureCollection } from "./mocks/geojson-feature-collection";
 
+function imageResponse() {
+  if (typeof File !== "undefined" && File) {
+    return new File(["foo"], "foo.png", { type: "image/png" });
+  } else {
+    const fs = require("fs");
+    return fs.createReadStream(
+      "./packages/arcgis-rest-request/test/mocks/foo.png"
+    );
+  }
+}
+
 describe("request()", () => {
   afterEach(fetchMock.restore);
 
@@ -91,6 +102,36 @@ describe("request()", () => {
         fail(e);
       });
   });
+  it("should make a basic POST request for binary data", done => {
+    fetchMock.once("*", imageResponse());
+
+    request(
+      "https://server/arcgis/rest/services/Custom/ImageServer/exportImage",
+      {
+        params: {
+          bbox: "-8529110,4764085,-8528610,4764085",
+          bboxSR: "102100",
+          size: "400,400",
+          imageSR: "102100",
+          format: "png8",
+          f: "image"
+        }
+      }
+    )
+      .then(response => {
+        const [url, options]: [string, RequestInit] = fetchMock.lastCall("*");
+        expect(url).toEqual(
+          "https://server/arcgis/rest/services/Custom/ImageServer/exportImage"
+        );
+        expect(options.method).toBe("POST");
+        expect(options.body).toContain("f=image");
+        // to do: introspect blob response?
+        done();
+      })
+      .catch(e => {
+        fail(e);
+      });
+  });
 
   it("should make a basic GET request for geojson", done => {
     fetchMock.once("*", GeoJSONFeatureCollection);