Speed, stability, community and that is made in Typescript.

With newer versions of npm or yarn, it's not a problem thanks to the lock file. Take in consideration that this file must be added to your control version so the team can really take advantage of this feature.

Redux is easy for pure functions (basically action creators that return objects and reducers). const addTodo = (todo) => ({ type: 'ADD_TODO' , todo }); expect(addTodo({ foo: 'bar' })).toEqual({ type: 'ADD_TODO' , todo: { foo: 'bar' } }); Reducers is the same. Just call the function with a initial state and an action and check the returned object. When it comes to action creators with thunks, it's a little harder. You can check here: Your title here Finally, for React you can use the tools that facebook gives you. I personally like Enzyme .