2017阿里前端笔试

男娘i 2022-03-15 08:22 204阅读 0赞

1、

![复制代码][copycode.gif]

![复制代码][copycode.gif]

主要考察引用对象的引用地址是否相同

2、

![复制代码][copycode.gif]

<body>
        <div id="J_container">
            <div id="div2">
                <div id="div1">点我</div>        
            </div>
        </div>
            <script>
            var div1 = document.getElementById('div1');
            var div2 = document.getElementById('div2');
            div1.addEventListener('click', () => {console.log('a')}, true);
            div2.addEventListener('click', () => {console.log('b')});
            div1.addEventListener('click', () => {console.log('c')}, false);
            div2.addEventListener('click', () => {console.log('d')}, true);
        </script>
    </body>

![复制代码][copycode.gif]

输出的顺序是： d a c b

**第一道编程题：**

要求：

![1115270-20170825001350543-2078292348.png][]

我的解答：

![复制代码][copycode.gif]

![复制代码][copycode.gif]

**第二道编程题：**

要求：

![1115270-20170823203926871-40818746.png][]

我的解答：

![复制代码][copycode.gif]

class EventEmitter {
                /* 在此处填写实现 */
                constructor(){
                    this.eventlist = {};
                    this.onceEventlist = {};
                }
                fire(obj){
                    const { type, value } = obj;
                    let _run = 1;
                    let _find = function(list){
                        for(let i in list){
                            if(i === type){
                                for(let j in list[i]){
                                    list[i][j](value);
                                    if( _run ){
                                        delete list[i];
                                    }
                                }
                            }
                        }
                        _run = 0;
                    };
                    _find(this.onceEventlist);
                    _find(this.eventlist);
                }
                on(event, fn){
                    this.eventlist[event] = {};
                    this.eventlist[event][fn.name] = fn;
                }
                off(event, fn){
                    if(this.eventlist[event]){
                        delete this.eventlist[event][fn.name];
                    }
                }
                once(event, fn){
                    this.onceEventlist[event] = {};
                    this.onceEventlist[event][fn.name] = fn;
                }
            }
    
            const emitter = new EventEmitter();
    
            const handler = function(evt) {
                console.log(1, evt);
            };
            emitter.on('foo', handler);
    
            emitter.once('foo', function(evt) {
                console.log(2, evt);
            });
    
            emitter.fire({ type: 'foo', value: 'hello' });
            emitter.fire({ type: 'foo', value: 'world' });
            emitter.off('foo', handler);
            emitter.fire({ type: 'foo', value: 'test' });

![复制代码][copycode.gif]

三、其它

一道模板解析习题

![1115270-20170912193719328-565082152.png][]

想法就是通过正则解析：

![复制代码][copycode.gif]

![复制代码][copycode.gif]

[copycode.gif]: /images/20220315/83c9e6f84aac44d1bfeff8ffb152c65e.png
[1115270-20170825001350543-2078292348.png]: /images/20220315/9636d34cce2c493ebf0b1d737cf6cf23.png
[1115270-20170823203926871-40818746.png]: /images/20220315/606e46118f4f415bba1799e5cb68fe0d.png
[1115270-20170912193719328-565082152.png]: /images/20220315/09967789dd964b4aa6a93e6007749a01.png