diff --git a/polygerrit-ui/app/.eslintrc.json b/polygerrit-ui/app/.eslintrc.json
index b5d3dae..97151f2 100644
--- a/polygerrit-ui/app/.eslintrc.json
+++ b/polygerrit-ui/app/.eslintrc.json
@@ -63,7 +63,6 @@
     "object-shorthand": ["error", "always"],
     "prefer-arrow-callback": "error",
     "prefer-const": "error",
-    "prefer-promise-reject-errors": "off",
     "prefer-spread": "error",
     "quote-props": ["error", "consistent-as-needed"],
     "require-jsdoc": "off",
diff --git a/polygerrit-ui/app/behaviors/gr-patch-set-behavior/gr-patch-set-behavior.html b/polygerrit-ui/app/behaviors/gr-patch-set-behavior/gr-patch-set-behavior.html
index d4e83d9..7e68669 100644
--- a/polygerrit-ui/app/behaviors/gr-patch-set-behavior/gr-patch-set-behavior.html
+++ b/polygerrit-ui/app/behaviors/gr-patch-set-behavior/gr-patch-set-behavior.html
@@ -232,7 +232,8 @@
       return restAPI.getChangeDetail(change._number)
           .then(detail => {
             if (!detail) {
-              return Promise.reject('Unable to check for latest patchset.');
+              const error = new Error('Unable to check for latest patchset.');
+              return Promise.reject(error);
             }
             const actualLatest = Gerrit.PatchSetBehavior.computeLatestPatchNum(
                 Gerrit.PatchSetBehavior.computeAllPatchSets(detail));
diff --git a/polygerrit-ui/app/elements/admin/gr-group-members/gr-group-members_test.html b/polygerrit-ui/app/elements/admin/gr-group-members/gr-group-members_test.html
index 81123e7..b86d971 100644
--- a/polygerrit-ui/app/elements/admin/gr-group-members/gr-group-members_test.html
+++ b/polygerrit-ui/app/elements/admin/gr-group-members/gr-group-members_test.html
@@ -233,9 +233,10 @@
       const memberName = 'bad-name';
       const alertStub = sandbox.stub();
       element.addEventListener('show-alert', alertStub);
-
+      const error = new Error('error');
+      error.status = 404;
       sandbox.stub(element.$.restAPI, 'saveGroupMembers',
-          () => Promise.reject({status: 404}));
+          () => Promise.reject(error));
 
       element.$.groupMemberSearchInput.text = memberName;
       element.$.groupMemberSearchInput.value = 1234;
diff --git a/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions_test.html b/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions_test.html
index 89d4f1f..c41d4e4 100644
--- a/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions_test.html
+++ b/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions_test.html
@@ -64,7 +64,9 @@
           });
         },
         send(method, url, payload) {
-          if (method !== 'POST') { return Promise.reject('bad method'); }
+          if (method !== 'POST') {
+            return Promise.reject(new Error('bad method'));
+          }
 
           if (url === '/changes/test~42/revisions/2/submit') {
             return Promise.resolve({
@@ -78,7 +80,7 @@
             });
           }
 
-          return Promise.reject('bad url');
+          return Promise.reject(new Error('bad url'));
         },
         getProjectConfig() { return Promise.resolve({}); },
       });
diff --git a/polygerrit-ui/app/elements/core/gr-router/gr-router.js b/polygerrit-ui/app/elements/core/gr-router/gr-router.js
index 7bb4656..cc55974 100644
--- a/polygerrit-ui/app/elements/core/gr-router/gr-router.js
+++ b/polygerrit-ui/app/elements/core/gr-router/gr-router.js
@@ -622,7 +622,7 @@
           return Promise.resolve();
         } else {
           this._redirectToLogin(data.canonicalPath);
-          return Promise.reject();
+          return Promise.reject(new Error());
         }
       });
     },
diff --git a/polygerrit-ui/app/elements/settings/gr-gpg-editor/gr-gpg-editor_test.html b/polygerrit-ui/app/elements/settings/gr-gpg-editor/gr-gpg-editor_test.html
index 13b3152..0a2ae78 100644
--- a/polygerrit-ui/app/elements/settings/gr-gpg-editor/gr-gpg-editor_test.html
+++ b/polygerrit-ui/app/elements/settings/gr-gpg-editor/gr-gpg-editor_test.html
@@ -169,7 +169,7 @@
       const newKeyString = 'not even close to valid';
 
       const addStub = sinon.stub(element.$.restAPI, 'addAccountGPGKey',
-          () => { return Promise.reject(); });
+          () => { return Promise.reject(new Error('error')); });
 
       element._newKey = newKeyString;
 
diff --git a/polygerrit-ui/app/elements/settings/gr-ssh-editor/gr-ssh-editor_test.html b/polygerrit-ui/app/elements/settings/gr-ssh-editor/gr-ssh-editor_test.html
index 8607948..1785d1f 100644
--- a/polygerrit-ui/app/elements/settings/gr-ssh-editor/gr-ssh-editor_test.html
+++ b/polygerrit-ui/app/elements/settings/gr-ssh-editor/gr-ssh-editor_test.html
@@ -155,7 +155,7 @@
       const newKeyString = 'not even close to valid';
 
       const addStub = sinon.stub(element.$.restAPI, 'addAccountSSHKey',
-          () => { return Promise.reject(); });
+          () => { return Promise.reject(new Error('error')); });
 
       element._newKey = newKeyString;
 
diff --git a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-plugin-action-context_test.html b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-plugin-action-context_test.html
index bf6a046..ca87956 100644
--- a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-plugin-action-context_test.html
+++ b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-plugin-action-context_test.html
@@ -135,7 +135,7 @@
         __key: 'key',
         __url: '/changes/1/revisions/2/foo~bar',
       };
-      const sendStub = sandbox.stub().returns(Promise.reject('boom'));
+      const sendStub = sandbox.stub().returns(Promise.reject(new Error('boom')));
       sandbox.stub(plugin, 'restApi').returns({
         send: sendStub,
       });
diff --git a/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface.js b/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface.js
index 09eff80..2c4404d 100644
--- a/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface.js
+++ b/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface.js
@@ -2506,7 +2506,9 @@
     _fetchB64File(url) {
       return this._fetch({url: this.getBaseUrl() + url})
           .then(response => {
-            if (!response.ok) { return Promise.reject(response.statusText); }
+            if (!response.ok) {
+              return Promise.reject(new Error(response.statusText));
+            }
             const type = response.headers.get('X-FYI-Content-Type');
             return response.text()
                 .then(text => {
@@ -2666,12 +2668,12 @@
       return this._send(req)
           .then(response => {
             if (response.status < 200 && response.status >= 300) {
-              return Promise.reject();
+              return Promise.reject(new Error('error'));
             }
             return this.getResponseObject(response);
           })
           .then(obj => {
-            if (!obj.valid) { return Promise.reject(); }
+            if (!obj.valid) { return Promise.reject(new Error('error')); }
             return obj;
           });
     },
@@ -2701,12 +2703,12 @@
       return this._send(req)
           .then(response => {
             if (response.status < 200 && response.status >= 300) {
-              return Promise.reject();
+              return Promise.reject(new Error('error'));
             }
             return this.getResponseObject(response);
           })
           .then(obj => {
-            if (!obj) { return Promise.reject(); }
+            if (!obj) { return Promise.reject(new Error('error')); }
             return obj;
           });
     },
diff --git a/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface_test.html b/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface_test.html
index 5d4a3b0..4ab1e04 100644
--- a/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface_test.html
+++ b/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface_test.html
@@ -88,10 +88,10 @@
     });
 
     test('cached promise', done => {
-      const promise = Promise.reject('foo');
+      const promise = Promise.reject(new Error('foo'));
       element._cache.set('/foo', promise);
       element._fetchSharedCacheURL({url: '/foo'}).catch(p => {
-        assert.equal(p, 'foo');
+        assert.equal(p.message, 'foo');
         done();
       });
     });
@@ -455,7 +455,7 @@
         status: 403,
       };
       window.fetch.onFirstCall().returns(
-          Promise.reject({message: 'Failed to fetch'}));
+          Promise.reject(new Error('Failed to fetch')));
       window.fetch.onSecondCall().returns(Promise.resolve(fakeAuthResponse));
       // Emulate logged in.
       element._cache.set('/accounts/self/detail', {});
@@ -507,7 +507,7 @@
       element._cache.set('/accounts/self/detail', true);
       sandbox.spy(element, 'checkCredentials');
       sandbox.stub(window, 'fetch', url => {
-        return Promise.reject({message: 'Failed to fetch'});
+        return Promise.reject(new Error('Failed to fetch'));
       });
       return element.getConfig(true)
           .catch(err => undefined)