redux-saga - sagaMiddleware.run对Generator Function的封装

 /*
    generator functions并不能保证Promise函数yield的顺序.
    但是sagaMiddleware.run函数对Generator进行了封装对于yield返回的结果在generator中可以保证执行的顺序。
    */
    var testSage = function*(){
        var value1 = yield delay(1000,2)
        console.log('step 1')
        var value2 = yield delay(2000,2)
        console.log('step 2')
        var value3 = yield delay(3000,2)
        console.log('step 3')
        var result= value1 + value2 + value3;
        console.log('result',result);
        yield result;
    }
    sagaMiddleware.run(testSage)