Redux Sample JS Bin, source http://jsbin.com/qavifum

jsbin.qavifum.js

const counter = (state = 0, action) => {
	switch(action.type){
		case 'INCREMENT':
			return state + 1;
		case 'DECREMENT':
			return state - 1;
		default:
			return state;
	}
}

const { createStore } = Redux;

// describe("Redux Texts", function(){
//   it("Tests passed", function(){
//     expect(counter(0, {type: 'INCREMENT'})).toEqual(1);
// 		expect(counter(3, {type: 'INCREMENT'})).toEqual(4);
		
// 		expect(counter(4, {type: 'DECREMENT'})).toEqual(3);
// 		expect(counter(1, {type: 'DECREMENT'})).toEqual(0);
// 		expect(counter(undefined, {})).toEqual(0);
//   });
// });

const store = createStore(counter);

const render = () => {
	document.body.innerText = store.getState();
};

store.subscribe(render);
render();

document.addEventListener('click', _ => {
	store.dispatch({type: 'INCREMENT'});
});