javascript - 使用 setTimeout() 嵌套回调；

Question

如何将这条匿名函数定义链重写为单独的函数，使其更易于维护和阅读？谢谢！

function animation(){

    var timeout;
    timeout=timeoutsetTimeout(function(){
        console.log('step1')

        timeout=setTimeout(function(){
            console.log('step2')

            timeout=setTimeout(function(){                                  
                console.log('almost there')

                setTimeout(function(){

                        console.log('grand finale')

                    }, 300);

            }, 1000);


        }, 2000);


    }, 5300);
}

Answer 1

方便地，您可以在 JS 中使用闭包代替 IOC 或 DI：

function animation(){

    var timeout;

    function one(){
        console.log('step1');
        timeout=setTimeout(two, 2000);
    }

    function two(){
        console.log('step2');
        timeout=setTimeout(three, 1000);
    }

    function three(){
        console.log('almost there');
        timeout=setTimeout(four, 300);
    }

    function four(){
        timeout=console.log('grand finale');
    }

   return timeout=setTimeout(one, 5300);

}