Add Joi.func().class()

lib/language.js

@@ -73,7 +73,8 @@ exports.errors = {
         arity: 'must have an arity of {{n}}',
         minArity: 'must have an arity greater or equal to {{n}}',
         maxArity: 'must have an arity lesser or equal to {{n}}',
-        ref: 'must be a Joi reference'
+        ref: 'must be a Joi reference',
+        class: 'must be a class'
     },
     lazy: {
         base: '!!schema error: lazy schema must be set',

lib/types/func/index.js

@@ -62,7 +62,6 @@ internals.Func = class extends ObjectType.constructor {
         });
     }
 
-
     ref() {
 
         return this._test('ref', null, function (value, state, options) {
@@ -74,6 +73,18 @@ internals.Func = class extends ObjectType.constructor {
             return this.createError('function.ref', null, state, options);
         });
     }
+
+    class() {
+
+        return this._test('class', null, function (value, state, options) {
+
+            if ((/^\s*class\s/).test(value.toString())) {
+                return value;
+            }
+
+            return this.createError('function.class', null, state, options);
+        });
+    }
 };
 
 module.exports = new internals.Func();

test/types/function.js

@@ -366,3 +366,57 @@ describe('func', () => {
         ], done);
     });
 });
+
+describe('func().class()', () => {
+
+    it('should differentiate between classes and functions', (done) => {
+
+        const classSchema = Joi.object({
+            _class: Joi.func().class()
+        });
+
+        const testFunc = function () {};
+        const testClass = class MyClass {};
+
+        Helper.validate(classSchema, [
+            [{ _class: testClass }, true],
+            [{ _class: testFunc }, false, null, {
+                message: 'child "_class" fails because ["_class" must be a class]',
+                details: [{
+                    message: '"_class" must be a class',
+                    path: ['_class'],
+                    type: 'function.class',
+                    context: { key: '_class', label: '_class' }
+                }]
+            }]
+        ], done);
+    });
+
+    it('refuses class look-alikes and bad values', (done) => {
+
+        const classSchema = Joi.object({
+            _class: Joi.func().class()
+        });
+
+        Helper.validate(classSchema, [
+            [{ _class: ['class '] }, false, null, {
+                message: 'child "_class" fails because ["_class" must be a Function]',
+                details: [{
+                    message: '"_class" must be a Function',
+                    path: ['_class'],
+                    type: 'function.base',
+                    context: { key: '_class', label: '_class' }
+                }]
+            }],
+            [{ _class: null }, false, null, {
+                message: 'child "_class" fails because ["_class" must be a Function]',
+                details: [{
+                    message: '"_class" must be a Function',
+                    path: ['_class'],
+                    type: 'function.base',
+                    context: { key: '_class', label: '_class' }
+                }]
+            }]
+        ], done);
+    });
+});