jss: Add definitions for createGenerateClassName

types/jss/index.d.ts

@@ -3,6 +3,7 @@
 // Definitions by: Brenton Simpson <https://github.com/appsforartists>
 //                 Oleg Slobodskoi <https://github.com/kof>
 //                 Thomas Crockett <https://github.com/pelotom>
+//                 Sebastian Silbermann <https://github.com/eps1lon>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 // TypeScript Version: 2.3
 
@@ -137,6 +138,10 @@ export declare class JSS {
  * Creates a new instance of JSS.
  */
 export function create(options?: Partial<JSSOptions>): JSS;
+/**
+ * Creates a GenerateClassName function
+ */
+export function createGenerateClassName(): GenerateClassName;
 declare const sharedInstance: JSS;
 /**
  * A global JSS instance.

types/jss/jss-tests.ts

@@ -2,11 +2,12 @@
 
 import {
 	create as createJSS,
+	createGenerateClassName,
 	SheetsRegistry,
 	default as sharedInstance,
 } from 'jss';
 
-const jss = createJSS().setup({});
+const jss = createJSS().setup({ createGenerateClassName });
 jss.use({}, {}); // $ExpectType JSS
 
 const styleSheet = jss.createStyleSheet<string>(
@@ -46,6 +47,9 @@ const rule = attachedStyleSheet.addRule('dynamicRule', { color: 'indigo' });
 rule.prop('border-radius', 5).prop('color'); // $ExpectType string
 attachedStyleSheet.classes.dynamicRule; // $ExpectType string
 
+const generateClassName = createGenerateClassName();
+const dynamicRuleClassName = generateClassName(rule, attachedStyleSheet);
+
 attachedStyleSheet.deleteRule('dynamicRule');
 
 // test that `addRule` supports the shorthand signature