/* Copyright 2019 Google LLC. All Rights Reserved.

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 queryString from 'query-string';
import { observable, computed } from 'mobx';

export type Variant = 'a' | 'b';

export class FeatureFlags {
  @observable readonly variant: Variant = 'a';

  @computed get baseline() {
    return this.variant === 'b';
  }

  constructor() {
    const parsed = queryString.parse(window.location.search);
    const { variant } = parsed;
    if (variant === 'b') {
      this.variant = variant;
    }
  }
}

export default new FeatureFlags();

/* Copyright 2019 Google LLC. All Rights Reserved.

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 queryString from 'query-string';

export class FeatureFlags {
  readonly baseline: boolean = false;

  constructor() {
    const parsed = queryString.parse(window.location.search);
    const { baseline } = parsed;
    if (baseline === 'true') {
      this.baseline = true;
    }
  }
}

export default new FeatureFlags();

--- 
+++ 
@@ -14,15 +14,22 @@
 ==============================================================================*/
 
 import queryString from 'query-string';
+import { observable, computed } from 'mobx';
+
+export type Variant = 'a' | 'b';
 
 export class FeatureFlags {
-  readonly baseline: boolean = false;
+  @observable readonly variant: Variant = 'a';
+
+  @computed get baseline() {
+    return this.variant === 'b';
+  }
 
   constructor() {
     const parsed = queryString.parse(window.location.search);
-    const { baseline } = parsed;
-    if (baseline === 'true') {
-      this.baseline = true;
+    const { variant } = parsed;
+    if (variant === 'b') {
+      this.variant = variant;
     }
   }
 }
Rename baseline query param to variant=b
