/**
 * Feature flags.
 *
 * Site Kit by Google, Copyright 2021 Google LLC
 *
 * 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
 *
 *     https://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.
 */

export const enabledFeatures = global?._googlesitekitBaseData?.enabledFeatures || [];

/**
 * Returns true if a feature is enabled; false otherwise.
 *
 * @since 1.25.0
 *
 * @param {string} feature          The name of the feature to check.
 * @param {?Array} _enabledFeatures Optional. The list of enabled features. Uses `enabledFeatures` set by the server in a global JS variable, by default.
 * @return {boolean} `true` if a feature is enabled; `false` otherwise.
 */
export const isFeatureEnabled = ( feature, _enabledFeatures = enabledFeatures ) => {
	return _enabledFeatures.includes( feature );
};

/**
 * Feature flags.
 *
 * Site Kit by Google, Copyright 2021 Google LLC
 *
 * 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
 *
 *     https://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.
 */

export const enabledFeatures = new Set( global?._googlesitekitBaseData?.enabledFeatures || [] );

/**
 * Returns true if a feature is enabled; false otherwise.
 *
 * @since 1.25.0
 *
 * @param {string} feature            The name of the feature to check.
 * @param {Set}    [_enabledFeatures] Optional. The set of enabled features. Uses `enabledFeatures` set by the server in a global JS variable, by default.
 * @return {boolean} `true` if a feature is enabled; `false` otherwise.
 */
export const isFeatureEnabled = ( feature, _enabledFeatures = enabledFeatures ) => {
	return _enabledFeatures.has( feature );
};

Update enabledFeatures to use a Set.
Update enabledFeatures to use a Set.

This also fixes a bug where enabled features could be mutated via the global value as it was not dereferenced before.
