写一个单例构造的对话框

前言

项目中，当需要用户处理事务，又不希望跳转页面以致打断工作流程时，我们会经常使用到对话框去承载相应的操作。虽然用得多，但是很多人其实并不知道怎么去写。饶有兴趣，自己尝试写了一个。

API

参数	说明	类型	默认值
afterClose	Modal 完全关闭后的回调	function	无
cancelText	取消按钮文字	string	取消
closable	是否显示右上角的关闭按钮	boolean	true
destroyOnClose	关闭时销毁 Modal	boolean	false
footer	底部内容，当不需要默认底部按钮时，可以设为 false	boolean	true
maskClosable	点击蒙层是否允许关闭	boolean	true
okText	确认按钮文字	string	确定
title	标题	string|html节点	标题
width	宽度	number	500
zIndex	设置 Modal 的 z-index	number	1000
keyboard	是否支持键盘esc关闭	boolean	true
onCancel	点击遮罩层或右上角叉或取消按钮的回调	function(e)	无
onOk	点击确定回调	function(e)	无

methods

参数	说明	使用形式
set	已覆盖默认的形式，设置新的属性，内部 Object.assign(this.options, newOptions)	model.set(newOptions)
open	打开对话框	model.open()
close	关闭对话框	model.close()
destroy	与close的区别在于，会从节点上删除	model.destroy()

---

代码

对话框全局中使用一个就够了，为了防止生成多个对话框，我们使用单例构造

var Dialog = (function () {
    var instance;
    return function (options) {
        if (!instance) {
            instance = new Modal(options);
        }
        return instance;
    }
})()

这里主要运用到了闭包中的特性

modal.js代码

var Dialog = (function () {
    var instance;
    return function (options) {
        if (!instance) {
            instance = new Modal(options);
        }
        return instance;
    }
})()

class Modal {
    constructor(options) {
        //默认属性
        this.initOptions = {
            title: '标题',
            maskClosable: true,
            header: true,
            footer: true,
            closable: true,
            okText: '确 定',
            cancelText: '取 消',
            destroyOnClose: false,
            keyboard: true,
            zIndex: 1000,
            width: 500,
            afterClose: null
        }
        this.options = Object.assign({}, this.initOptions, options);

        this.instance = document.createElement('div');//节点实例，因为只需要一个模态框，这里设置节点就可以了
        this.mounted = false; //是否挂载在节点上
    }

    //处理模态框的点击事件
    _modalClick(e) {
        var className = e.target.className;
        //匹配类名，例如 带有 class='modal-close' 的元素点击可以关闭模态框
        if (new RegExp("(\\s|^)modal-close(\\s|$)").test(className)) {
            this.cancel();   //关闭模态框
        } else if (new RegExp("(\\s|^)modal-onOk(\\s|$)").test(className)) {
            this.onOk();     //执行确定按钮的回调
        } else if (new RegExp("(\\s|^)modal-container(\\s|$)").test(className)) {
            this.outSideClick(); //模态框外的点击
        }
    }

    //处理键盘ESC关闭
    _escClose(e) {
        var code = e.keyCode;
        if (code === 27) {
            this.cancel();
        }
    }

    //渲染模态框节点
    render() {
        var modal = this.instance;
        modal.style.zIndex = this.options.zIndex;
        modal.className = 'modal-container';
        var closeIcon = this.options.closable ? `<span class="modal-close">X</span>` : '';
        var header = this.options.header ?
            (this.options.header === true ?
                `<div class='modal-header'>${this.options.title}
                                    ${closeIcon}
                                </div>` :
                this.options.header) :
            '';
        var footer = this.options.footer ?
            (this.options.footer === true ?
                `<div class='modal-footer'>
                                <span class="modal-btn modal-close">${this.options.cancelText}</span>
                                <span class="modal-btn  modal-onOk modal-btn-primary">${this.options.okText}</span>
                            </div>` :
                this.options.footer) :
            '';
        modal.innerHTML = `<div class="modal" style="width: ${this.options.width}px">
                                ${header}
                                <div class='modal-content'>${this.options.content}</div>
                                ${footer}
                            </div>`;
    }


    //蒙层点击关闭
    outSideClick() {
        if (this.options.maskClosable) {
            this.close();
        }
    }

    //处理监听
    listen() {
        this._modalClick = this._modalClick.bind(this);
        this.instance.addEventListener('click', this._modalClick);
        
        if(this.options.keyboard){
            this._escClose = this._escClose.bind(this);
            window.addEventListener('keyup', this._escClose);
        }
    }

    cancel(){
        if(typeof this.options.onCancel === "function"){
            this.options.onCancel();
        }
        this.close();
    }

    //点击确定回调
    onOk() {
        this
            .options
            .onOkFn();
        this.close();
    }


    /****************** 提供的方法  ********************* */
    //设置属性
    set(options) {
        Object.assign(this.options, options)
        this.render()
    }

    //打开模态框
    open() {
        var modal = this.instance;
        //实例如果没挂载
        if (!this.mounted) {
            this.mounted = true;
            this.render();
            document.body.appendChild(modal);
            this.listen()
        }
        removeClass(modal, 'close');
        addClass(modal, 'open');
    }

    //关闭模态框
    close() {
        var modal = this.instance
        removeClass(modal, 'open');
        addClass(modal, 'close');
        if (this.options.destroyOnClose === true) {
            this.destroy();
        }
        if (typeof this.options.afterClose === "function") {
            var afterClose = this.options.afterClose.bind(this);
            setTimeout(afterClose, 0);
        }
    }
    //从节点上移除模态框
    destroy() {
        this.instance.removeEventListener('click', this._modalClick);//移除click监听
        window.removeEventListener('keyup', this._escClose);//移除keyup监听
        document.body.removeChild(this.instance);//移除模态框节点
        this.mounted = false;
    }

}

function hasClass(elements, cName) {
    return !!elements
        .className
        .match(new RegExp("(\\s|^)" + cName + "(\\s|$)"));
};
function addClass(elements, cName) {
    if (!hasClass(elements, cName)) {
        elements.className += " " + cName;
    };
};
function removeClass(elements, cName) {
    if (hasClass(elements, cName)) {
        elements.className = elements
            .className
            .replace(new RegExp("(\\s|^)" + cName + "(\\s|$)"), "");
    };
};

modal.css

@keyframes openAnimate {
    0% {
        opacity: 0;
    }
    100%{
        opacity: 1;
    }
}

.open{
    display: block !important;
    animation: openAnimate .8s;
}
.close{
    display: none;
}
.modal-container {
    position: fixed;
    top: 0;
    right: 0;
    left: 0;
    bottom: 0;
    background-color: #373737;
    background-color: rgba(0,0,0,.65);
    margin: auto;
    filter: alpha(opacity=50);
    text-align: center;
    font-size: 0;
    white-space: nowrap;
    overflow: auto;
    display: none;
}

.modal-container:after {
    content: '';
    display: inline-block;
    height: 100%;
    vertical-align: middle;
}

.modal {
    display: inline-block;
    vertical-align: middle;
    text-align: left;
    font-size: 14px;
    background-color: #fff;
    border: 0;
    border-radius: 4px;
    background-clip: padding-box;
    box-shadow: 0 4px 12px rgba(0,0,0,.15);
}

.modal-header{
    padding: 16px 24px;
    border-radius: 4px 4px 0 0;
    background: #fff;
    color: rgba(0,0,0,.65);
    border-bottom: 1px solid #e8e8e8;
}
.modal-close{
    float: right;
    cursor: pointer;
}
.modal-content{
    padding: 24px;
    font-size: 14px;
    line-height: 1.5;
    word-wrap: break-word;
    min-height: 200px;
}

.modal-footer {
    border-top: 1px solid #e8e8e8;
    padding: 10px 16px;
    text-align: right;
    border-radius: 0 0 4px 4px;
}

.modal-btn{
    line-height: 32px;
    display: inline-block;
    font-weight: 400;
    text-align: center;
    touch-action: manipulation;
    cursor: pointer;
    background-image: none;
    border: 1px solid transparent;
    white-space: nowrap;
    padding: 0 15px;
    font-size: 14px;
    border-radius: 4px;
    height: 32px;
    user-select: none;
    transition: all .3s cubic-bezier(.645,.045,.355,1);
    position: relative;
    color: rgba(0,0,0,.65);
    background-color: #fff;
    border-color: #d9d9d9;
    cursor: pointer;
}

.modal-btn-primary{
    color: #fff;
    background-color: #1890ff;
    border-color: #1890ff;
}

如何使用

<!DOCTYPE html>
<html lang="en">

    <head>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <meta http-equiv="X-UA-Compatible" content="ie=edge">
        <title>Document</title>
        <link rel="stylesheet" href="./modal.css">
    </head>

    <body>
        <button class="open">1</button>
        <button class="open">2</button>
        <button class="open">3</button>
        <script src="./modal.js"></script>
        <script src="./index.js"></script>
    </body>

</html>

index.js

var config = {
    title: '模态框标题',
    content: '',
    header: true,
    footer: true,
    destroyOnClose: true,
    onOkFn: function () {
        alert('提交成功')
    },
    afterClose: function(){
        alert('已经关闭')
    }
}
var modal = new Dialog(config);
var openBtns = document.querySelectorAll('.open');
openBtns.forEach(function (item, index) {
    item.onclick = function () {
        var option = {
            content: '这是第' + (index + 1) + '个'
        }
        modal.set(option)
        modal.open();
    }

})