[core/apis/definitions] added featureFlags definition

packages/core/src/api/apis/definitions/featureFlags.ts

@@ -0,0 +1,53 @@
+/*
+ * Copyright 2020 Spotify AB
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import ApiRef from '../ApiRef';
+import { FeatureFlagName } from '../../plugin/types';
+
+/**
+ * The feature flags API is used to toggle functionality to users across plugins and Backstage.
+ *
+ * Plugins can use this API to register feature flags that they have available
+ * for users to enable/disable, and this API will centralize the current user's
+ * state of which feature flags they would like to enable.
+ *
+ * This is ideal for Backstage plugins, as well as your own App, to trial incomplete
+ * or unstable upcoming features. Although there will be a common interface for users
+ * to enable and disable feature flags, this API acts as another way to enable/disable.
+ */
+export type FeatureFlagsApi = {
+  /**
+   * Get the current user's status of a Feature Flag
+   *
+   * @returns bool True if the current user has enabled the feature flag
+   */
+  getItem(name: FeatureFlagName): boolean;
+
+  /**
+   * Enable an registered feature flag.
+   */
+  enable(name: FeatureFlagName): void;
+
+  /**
+   * Disable an registered feature flag.
+   */
+  disable(name: FeatureFlagName): void;
+};
+
+export const featureFlagsApiRef = new ApiRef<FeatureFlagsApi>({
+  id: 'core.featureflags',
+  description: 'Used to toggle functionality in features across Backstage',
+});

packages/core/src/api/apis/definitions/index.ts

@@ -21,3 +21,4 @@
 // If you think some API definition is missing, please open an Issue or send a PR!
 
 export * from './error';
+export * from './featureFlags';