Add ability to abort a kfetch call.

src/ui/public/kfetch/index.js

@@ -32,7 +32,16 @@ class FetchError extends Error {
   }
 }
 
-export async function kfetch(fetchOptions, kibanaOptions) {
+export function kfetch(fetchOptions, kibanaOptions, isAbortable = false) {
+  let signal;
+  let abort;
+
+  if (isAbortable) {
+    const abortController = new AbortController();
+    signal = abortController.signal;
+    abort = abortController.abort.bind(abortController);
+  }
+
   // fetch specific options with defaults
   const { pathname, query, ...combinedFetchOptions } = merge(
     {
@@ -42,8 +51,9 @@ export async function kfetch(fetchOptions, kibanaOptions) {
         'Content-Type': 'application/json',
         'kbn-version': metadata.version,
       },
+      signal,
     },
-    fetchOptions
+    fetchOptions,
   );
 
   // kibana specific options with defaults
@@ -57,17 +67,28 @@ export async function kfetch(fetchOptions, kibanaOptions) {
     query,
   });
 
-  const res = await fetch(fullUrl, combinedFetchOptions);
+  const fetching = new Promise(async (resolve, reject) => {
+    const res = await fetch(fullUrl, combinedFetchOptions);
 
-  if (!res.ok) {
-    let body;
-    try {
-      body = await res.json();
-    } catch (err) {
-      // ignore error, may not be able to get body for response that is not ok
+    if (!res.ok) {
+      let body;
+      try {
+        body = await res.json();
+      } catch (err) {
+        // ignore error, may not be able to get body for response that is not ok
+      }
+      reject(new FetchError(res, body));
     }
-    throw new FetchError(res, body);
+
+    resolve(res.json());
+  });
+
+  if (isAbortable) {
+    return {
+      fetching,
+      abort,
+    };
   }
 
-  return res.json();
+  return fetching;
 }

src/ui/public/kfetch/index.test.js

@@ -114,4 +114,13 @@ describe('kfetch', () => {
       });
     });
   });
+
+  describe('isAbortable', () => {
+    it('should return an object with a fetching promise and an abort callback', () => {
+      const { fetching, abort } = kfetch({ pathname: 'my/path' }, {}, true);
+      expect(typeof fetching.then).toBe('function');
+      expect(typeof fetching.catch).toBe('function');
+      expect(typeof abort).toBe('function');
+    });
+  });
 });