Use `FilteredSearchTokenKeys` class directly for token handling

ee/app/assets/javascripts/filtered_search/filtered_search_token_keys_epics.js

-const tokenKeys = [{
+import FilteredSearchTokenKeys from '~/filtered_search/filtered_search_token_keys';
+
+const tokenKeys = [
+  {
     key: 'author',
     type: 'string',
     param: 'username',
     symbol: '@',
     icon: 'pencil',
     tag: '@author',
-}, {
+  },
+  {
     key: 'label',
     type: 'array',
     param: 'name[]',
     symbol: '~',
     icon: 'labels',
     tag: '~label',
-}];
+  },
+];
 
-const alternativeTokenKeys = [{
+const alternativeTokenKeys = [
+  {
     key: 'label',
     type: 'string',
     param: 'name',
     symbol: '~',
-}];
-
-const tokenKeysWithAlternative = tokenKeys.concat(alternativeTokenKeys);
+  },
+];
 
-const conditions = [{
+const conditions = [
+  {
     url: 'label_name[]=No+Label',
     tokenKey: 'label',
     value: 'none',
-}];
-
-export default class FilteredSearchTokenKeysEpics {
-  static get() {
-    return tokenKeys;
-  }
-
-  static getKeys() {
-    return tokenKeys.map(i => i.key);
-  }
-
-  static getAlternatives() {
-    return alternativeTokenKeys;
-  }
-
-  static getConditions() {
-    return conditions;
-  }
-
-  static searchByKey(key) {
-    return tokenKeys.find(tokenKey => tokenKey.key === key) || null;
-  }
-
-  static searchBySymbol(symbol) {
-    return tokenKeys.find(tokenKey => tokenKey.symbol === symbol) || null;
-  }
-
-  static searchByKeyParam(keyParam) {
-    return tokenKeysWithAlternative.find((tokenKey) => {
-      let tokenKeyParam = tokenKey.key;
-
-      // Replace hyphen with underscore to compare keyParam with tokenKeyParam
-      // e.g. 'my-reaction' => 'my_reaction'
-      tokenKeyParam = tokenKeyParam.replace('-', '_');
-
-      if (tokenKey.param) {
-        tokenKeyParam += `_${tokenKey.param}`;
-      }
-
-      return keyParam === tokenKeyParam;
-    }) || null;
-  }
+  },
+];
 
-  static searchByConditionUrl(url) {
-    return conditions.find(condition => condition.url === url) || null;
-  }
+const EpicsFilteredSearchTokenKeysEE = new FilteredSearchTokenKeys(
+  [...tokenKeys],
+  alternativeTokenKeys,
+  [...conditions],
+);
 
-  static searchByConditionKeyValue(key, value) {
-    return conditions
-      .find(condition => condition.tokenKey === key && condition.value === value) || null;
-  }
-}
+export default EpicsFilteredSearchTokenKeysEE;