Merge pull request #58 from bem-sdk/issue-53

fix(mod): should return `undefined` if entity is not modifier

Author: blond

README.md

@@ -37,7 +37,7 @@ const entityName = new BemEntityName({ block: 'button', elem: 'text' });
 
 entityName.block; // button
 entityName.elem;  // text
-entityName.mod;   // {}
+entityName.mod;   // undefined
 
 entityName.id;   // button__elem
 entityName.type; // elem
@@ -143,13 +143,16 @@ name.elem; // text
 
 The modifier of this entity.
 
-If entity is not modifier then returns empty object.
+**Important:** If entity is not a modifier then returns `undefined`.
 
 ```js
 const BemEntityName = require('bem-entity-name');
-const name = new BemEntityName({ block: 'button', mod: 'disabled' });
 
-name.mod; // { name: 'disabled', val: true }
+const blockName = new BemEntityName({ block: 'button' });
+const modName = new BemEntityName({ block: 'button', mod: 'disabled' });
+
+modName.mod;   // { name: 'disabled', val: true }
+blockName.mod; // undefined
 ```
 
 ### id

index.js

@@ -76,17 +76,20 @@ module.exports = class BemEntityName {
     /**
      * Returns the modifier of this entity.
      *
-     * If entity is not modifier then returns empty object.
+     * Important: If entity is not a modifier then returns `undefined`.
      *
      * @example
      * const BemEntityName = require('bem-entity-name');
-     * const name = new BemEntityName({ block: 'button', mod: 'disabled' });
      *
-     * console.log(name.mod); // { name: 'disabled', val: true }
+     * const blockName = new BemEntityName({ block: 'button' });
+     * const modName = new BemEntityName({ block: 'button', mod: 'disabled' });
+     *
+     * console.log(modName.mod);   // { name: 'disabled', val: true }
+     * console.log(blockName.mod); // undefined
      *
      * @returns {{mod: string, val: *}} entity modifier.
      */
-    get mod() { return this._data.mod || {}; }
+    get mod() { return this._data.mod; }
     /**
      * Returns the modifier name of this entity.
      *
@@ -95,7 +98,7 @@ module.exports = class BemEntityName {
      * @returns {string} entity modifier name.
      * @deprecated use `mod.name` instead.
      */
-    get modName() { return this.mod.name; }
+    get modName() { return this.mod && this.mod.name; }
     /**
      * Returns the modifier value of this entity.
      *
@@ -104,7 +107,7 @@ module.exports = class BemEntityName {
      * @returns {string} entity modifier name.
      * @deprecated use `mod.val` instead.
      */
-    get modVal() { return this.mod.val; }
+    get modVal() { return this.mod && this.mod.val; }
     /**
      * Returns id for this entity.
      *
@@ -127,8 +130,8 @@ module.exports = class BemEntityName {
         const entity = { block: this._data.block };
 
         this.elem && (entity.elem = this.elem);
-        this.mod.name && (entity.modName = this.mod.name);
-        this.mod.val && (entity.modVal = this.mod.val);
+        this.modName && (entity.modName = this.modName);
+        this.modVal && (entity.modVal = this.modVal);
 
         this._id = stringifyEntity(entity);
 

test/fields.test.js

@@ -38,10 +38,10 @@ test('should return `undefined` if entity is not element', t => {
     t.is(entity.elem, undefined);
 });
 
-test('should return empty object if entity is not modifier', t => {
+test('should return `undefined` if entity is not modifier', t => {
     const entity = new BemEntityName({ block: 'block' });
 
-    t.deepEqual(entity.mod, {});
+    t.deepEqual(entity.mod, undefined);
 });
 
 test('should return `undefined` in `modName` property if entity is not modifier', t => {