一些工具函数

util

var util = {
        loadCss: function(src) {
            var style = document.createElement('link');
            style.href = src;
            style.rel = 'stylesheet';
            style.type = 'text/css';
            document.getElementsByTagName('head').item(0).appendChild(style); 
        },
        loadJs: function(src, callback) {
            var head= document.getElementsByTagName('head')[0]; 
            var script= document.createElement('script'); 
            script.type= 'text/javascript'; 
            script.src= src;
            script.async = true;
            if (callback != null) {
                script.onload = script.onreadystatechange = function(){
                    if (script.ready) {
                        return false;
                    }
                    if (!script.readyState || script.readyState == "loaded" || script.readyState == 'complete') {
                        script.ready = true;
                        callback();
                    }
                };
            }
            head.appendChild(script); 
        },
        getCookie: function(name){
            var strCookie=document.cookie;
            var arrCookie=strCookie.split("; ");
            for(var i=0;i<arrCookie.length;i++){
                var arr=arrCookie[i].split("=");
                if(arr[0]==name)return arr[1];
            }
            return "";
        },
        deleteCookie: function (name){ 
           var date=new Date(); 
           date.setTime(date.getTime()-10000); 
           document.cookie=name+"=v; expire="+date.toGMTString(); 
        },

        mergeJson: function(oldJson, newJson) {
            // 合并两个json对象，对比old和new，如果不一样，则用new的。new没有的用new。最后返回old样式old json
            for(var name in oldJson) {
                if(!newJson[name]) {
                    newJson[name] = oldJson[name];
                }
            }
            return newJson;
        },
        scrollBottomMore: function() {
            $(window.document).scroll(function() {
                if($(window).scrollTop() + $(window).height() >= $(document).height() - 90) {
                   // doSomething();
               }
             });
        }
    };


/**
 * 在本地进行文件保存
 * @param  {String} data     要保存到本地的图片数据
 * @param  {String} filename 文件名
 * @param callback{Function}
 */
export function saveFile(filename, callback){
    var save_link = document.createElement('a');
    save_link.href = '/express/' + filename
    save_link.download = filename.replace('exports/', '')

    var event = document.createEvent('MouseEvents');
    event.initMouseEvent('click', true, false, window, 0, 0, 0, 0, 0, false, false, false, false, 0, null);
    save_link.dispatchEvent(event);
    callback && callback();
}

export function downloadHttp(config = {
    url: '',
    param: null,
    callback: null
}, httpType = 'GET') {
    let url = config.url
    let fetchConfig = {
        method: httpType,
        credentials: 'same-origin'
    }
    if(httpType === 'GET') {
        if(config.param) {
            url = config.url + '?' + qs.stringify(config.param, {
                arrayFormat: 'brackets'
            })
        }
    } else if(httpType === 'POST' || httpType === 'PUT' || httpType === 'PATCH') {
        fetchConfig.headers = {
            'Accept': 'application/json',
            'Content-Type': 'application/json'
        }
        if(config.param) {
            fetchConfig.body = JSON.stringify(config.param)
        }
    }

    fetch(url, fetchConfig)
    .then(res => {
        // node返回二进制数据
        return res.blob()
    })
    .then(blob => {
        var a = document.createElement("a");
        a.href = window.URL.createObjectURL(blob);
        a.download = config.param && config.param.title || 'NoName.txt';
        a.click()
        config.callback && config.callback(blob)
    })
    .catch((errors) => {
        console.error(errors)
        config.error && config.error(errors)
    })
}