sinon

You could use a closure. For example: var obj = { foo: function () { console.log(‘foo’); } }; var stub = (function () { var originalFoo = obj.foo; return sinon.stub(obj, ‘foo’, function () { console.log(‘stub’); originalFoo(); }); }()); JSFiddle

https://sinonjs.org/releases/latest/matchers/#sinonmatchany You can use sinon.match.any: method.get.withArgs(25, sinon.match.any, sinon.match.any);