- Add support for passing custom values for enum keys (via Object)

- Add support for reverse lookup in enum

2 files changed, 57 insertions, 9 deletions

diff --git a/app/lib/enum.js b/app/lib/enum.js
index a27bd37439..ac5df30d06 100644
--- a/app/lib/enum.js
+++ b/app/lib/enum.js
@@ -8,23 +8,47 @@ export default class Enum {
   /**
    * Creates an instance of EnumBase.
    * 
-   * @param {...string} ... - enum keys
+   * @param {...string|object} ... - enum keys
    * @memberOf Enum
    */
   constructor() {
-    const keys = [...arguments];
+    const items = [...arguments];
+    let allKeys = [];
+    let reverseMap = new Map();
 
-    for(const key of keys) {
-      Object.defineProperty(this, key, {
-        enumerable: true,
-        value: key,
-        writable: false
-      });
+    for(const item of items) {
+      if(typeof(item) === 'string') {
+        Object.defineProperty(this, item, {
+          enumerable: true,
+          value: item,
+          writable: false
+        });
+        allKeys.push(item);
+        reverseMap.set(item, item);
+      } else if(typeof(item) === 'object') {
+        for(const key of Object.keys(item)) {
+          Object.defineProperty(this, key, {
+            enumerable: true,
+            value: item[key],
+            writable: false
+          });
+          allKeys.push(key);
+          reverseMap.set(item[key], key);
+        }
+      } else {
+        throw new Error('Unsupported argument type: ' + typeof(item));
+      }
     }
 
     Object.defineProperty(this, 'allKeys', {
       enumerable: false,
-      value: keys,
+      value: allKeys,
+      writable: false
+    });
+    
+    Object.defineProperty(this, 'reverseMap', {
+      enumerable: false,
+      value: reverseMap,
       writable: false
     });
 
@@ -42,5 +66,17 @@ export default class Enum {
   isValid(key) { 
     return this.allKeys.includes(key); 
   }
+
+  /**
+   * Return key for value
+   * 
+   * @param {any} value
+   * @returns {any|undefined} returns undefined if key is not found
+   * 
+   * @memberOf Enum
+   */
+  reverse(value) {
+    return this.reverseMap.get(value);
+  }
 }
 
diff --git a/test/enum.spec.js b/test/enum.spec.js
index 554a35b922..013fbc4e0f 100644
--- a/test/enum.spec.js
+++ b/test/enum.spec.js
@@ -25,4 +25,16 @@ describe('enum', () => {
     const e = new Enum(...keys);
     expect(Object.keys(e)).to.be.deep.equal(keys);
   });
+
+  it('should do reverse lookup', () => {
+    const keys = { NORTH: 0, SOUTH: 1, WEST: 2, EAST: 3 };
+    const e = new Enum(keys);
+    expect(e.reverse(2)).to.be.equal('WEST');
+  });
+
+  it('should return undefined on reverse lookup failure', () => {
+    const keys = { NORTH: 0, SOUTH: 1, WEST: 2, EAST: 3 };
+    const e = new Enum(keys);
+    expect(e.reverse(1337)).to.be.undefined;
+  });
 });