Adding unit test and lint

src/scripts/choices.ts

@@ -46,6 +46,7 @@ import {
   isType,
   sortByScore,
   strToEl,
+  parseCustomProperties,
 } from './lib/utils';
 import { defaultState } from './reducers';
 import Store from './store/store';
@@ -290,7 +291,9 @@ class Choices implements Choices {
           disabled: option.disabled || option.parentNode.disabled,
           placeholder:
             option.value === '' || option.hasAttribute('placeholder'),
-          customProperties: this._parseCustomProperties(option.dataset['customProperties']),
+          customProperties: parseCustomProperties(
+            option.dataset.customProperties,
+          ),
         });
       });
     }
@@ -2429,17 +2432,6 @@ class Choices implements Choices {
 
     return null;
   }
-
-  _parseCustomProperties(customProperties): any {
-    if(typeof customProperties !== 'undefined') {
-      try {
-          return JSON.parse(customProperties)
-      } catch(e) {
-          return customProperties
-      }
-    }
-    return {}
-  }
 }
 
 export default Choices;

src/scripts/lib/utils.test.ts

@@ -15,6 +15,7 @@ import {
   sanitise,
   sortByAlpha,
   sortByScore,
+  parseCustomProperties,
 } from './utils';
 
 describe('utils', () => {
@@ -256,4 +257,25 @@ describe('utils', () => {
       expect(output).to.deep.equal(['baz']);
     });
   });
+
+  describe('_parseCustomProperties', () => {
+    describe('when custom properties are valid json', () => {
+      it('returns the properties as object', () => {
+        const customProperties = '{"description": "foo", "bar": "foo"}';
+        const result = { description: 'foo', bar: 'foo' };
+
+        const value = parseCustomProperties(customProperties);
+        expect(value).to.eql(result);
+      });
+    });
+    describe('when custom properties are undefined', () => {
+      it('returns an empty object', () => {
+        const customProperties = undefined;
+        const result = {};
+
+        const value = parseCustomProperties(customProperties);
+        expect(value).to.eql(result);
+      });
+    });
+  });
 });

src/scripts/lib/utils.ts

@@ -180,3 +180,15 @@ export const diff = (
 
   return aKeys.filter((i) => bKeys.indexOf(i) < 0);
 };
+
+export const parseCustomProperties = (customProperties): any => {
+  if (typeof customProperties !== 'undefined') {
+    try {
+      return JSON.parse(customProperties);
+    } catch (e) {
+      return customProperties;
+    }
+  }
+
+  return {};
+};