[New] mount/shallow: add regex support to .hasClass

docs/api/ReactWrapper/hasClass.md

@@ -5,22 +5,28 @@ Returns whether or not the wrapped node has a `className` prop including the pas
 
 #### Arguments
 
-1. `className` (`String`): A single class name.
+1. `className` (`String` | `RegExp`): A single class name or a regex expression.
 
 
 #### Returns
 
-`Boolean`: whether or not the wrapped node has the class.
+`Boolean`: whether or not the wrapped node has found the class name.
 
 
-#### Example
+#### Examples
 
 
 ```jsx
 const wrapper = mount(<MyComponent />);
 expect(wrapper.find('.my-button').hasClass('disabled')).to.equal(true);
 ```
 
+```jsx
+// Searching using RegExp works fine when classes were injected by a jss decorator
+const wrapper = mount(<MyComponent />);
+expect(wrapper.find('.my-button').hasClass(/(ComponentName)-(other)-(\d+)/)).to.equal(true);
+```
+
 ### Common Gotchas
 
 - `.hasClass()` expects a class name, NOT a CSS selector. `.hasClass('.foo')` should be

docs/api/ShallowWrapper/hasClass.md

@@ -5,7 +5,7 @@ Returns whether or not the wrapped node has a `className` prop including the pas
 
 #### Arguments
 
-1. `className` (`String`): A single class name.
+1. `className` (`String` | `RegExp`): A single class name or a regex expression.
 
 
 #### Returns
@@ -21,6 +21,12 @@ const wrapper = shallow(<MyComponent />);
 expect(wrapper.find('.my-button').hasClass('disabled')).to.equal(true);
 ```
 
+```jsx
+// Searching using RegExp works fine when classes were injected by a jss decorator
+const wrapper = mount(<MyComponent />);
+expect(wrapper.find('.my-button').hasClass(/(ComponentName)-(other)-(\d+)/)).to.equal(true);
+```
+
 ### Common Gotchas
 
 - `.hasClass()` expects a class name, NOT a CSS selector. `.hasClass('.foo')` should be

packages/enzyme-test-suite/package.json

@@ -56,4 +56,4 @@
     "eslint-plugin-react": "^7.12.4",
     "react-is": "^16.7.0"
   }
-}
+}

packages/enzyme-test-suite/test/RSTTraversal-spec.jsx

@@ -43,6 +43,16 @@ describe('RSTTraversal', () => {
       const node = $(<div className={classes} />);
       expect(hasClassName(node, 'foo-bar')).to.equal(true);
     });
+
+    it('works if searching with a RegExp', () => {
+      const node = $(<div className="ComponentName-classname-123" />);
+      expect(hasClassName(node, /(ComponentName)-(classname)-(\d+)/)).to.equal(true);
+    });
+
+    it('fails if searching for a missing classname with a RegExp', () => {
+      const node = $(<div className="ComponentName-classname-123 ComponentName-otherclassname-23" />);
+      expect(hasClassName(node, /(ComponentName)-(other)-(\d+)/)).to.equal(false);
+    });
   });
 
   describe('treeForEach', () => {

packages/enzyme/package.json

@@ -42,6 +42,7 @@
     "is-boolean-object": "^1.0.0",
     "is-callable": "^1.1.4",
     "is-number-object": "^1.0.3",
+    "is-regex": "^1.0.4",
     "is-string": "^1.0.4",
     "is-subset": "^0.1.1",
     "lodash.escape": "^4.0.1",

packages/enzyme/src/RSTTraversal.js

@@ -2,6 +2,7 @@ import flat from 'array.prototype.flat';
 import entries from 'object.entries';
 import isSubset from 'is-subset';
 import functionName from 'function.prototype.name';
+import isRegex from 'is-regex';
 import getAdapter from './getAdapter';
 
 export function propsOfNode(node) {
@@ -34,6 +35,7 @@ export function childrenOfNode(node) {
 export function hasClassName(node, className) {
   let classes = propsOfNode(node).className || '';
   classes = String(classes).replace(/\s/g, ' ');
+  if (isRegex(className)) return className.test(classes);
   return ` ${classes} `.indexOf(` ${className} `) > -1;
 }