fix(classname): fix zero mod value bug

Author: frontstall

packages/classname/classname.ts

@@ -49,6 +49,10 @@ export type Preset = {
   v?: string
 }
 
+function isEmpty(val: string | boolean | number | undefined) {
+  return !val && val !== 0
+}
+
 /**
  * BEM className configure function.
  *
@@ -81,7 +85,7 @@ export function withNaming(preset: Preset): ClassNameInitilizer {
 
           if (modVal === true) {
             className += modPrefix + k
-          } else if (modVal) {
+          } else if (!isEmpty(modVal)) {
             className += modPrefix + k + modValueDelimiter + modVal
           }
         }

packages/classname/test/classname.test.ts

@@ -49,7 +49,7 @@ describe('@bem-react/classname', () => {
 
       test('zero', () => {
         const b = cn('Block')
-        expect(b({ modName: '0' })).toEqual('Block Block_modName_0')
+        expect(b({ modName: '0', mod: 0 })).toEqual('Block Block_modName_0 Block_mod_0')
       })
 
       test('undefined', () => {
@@ -211,7 +211,7 @@ describe('@bem-react/classname', () => {
 
       test('zero', () => {
         const b = cCn('block')
-        expect(b({ modName: '0' })).toEqual('block block_modName_0')
+        expect(b({ modName: '0', mod: 0 })).toEqual('block block_modName_0 block_mod_0')
       })
     })
   })