js常用知识总结

格式化时间字符串

String.prototype.formatTime = function formatTime(template) {
    // 1.根据操作的时间字符串获取年月日小时分钟秒等信息
    let arr = this.match(/\d+/g).map(item => {
        return item.length < 2 ? '0' + item : item;
    });

    // 2.解析格式化的模板,找到对应的时间,替换模板中的内容
    template = template || '{0}年{1}月{2}日 {3}时{4}分{5}秒';
    return template.replace(/\{(\d+)\}/g, (_, group) => {
        return arr[group] || "00";
    });
};

处理URL参数

 

(proto => {
    function queryURLParams() {
        let obj = {};
        this.replace(/([^?=&#]+)=([^?=&#]+)/g, (_, key, value) => obj[key] = value);
        this.replace(/#([^?=&#]+)/g, (_, hash) => obj['HASH'] = hash);
        return obj;
    }
    proto.queryURLParams = queryURLParams;
})(String.prototype);

console.log('http://www.xxxxxxx.cn/?lx=1&name=JS&from=baidu#video'.queryURLParams());
// 输出一个对象

实现千分符

String.prototype.millimeter = function millimeter() {
    return this.replace(/\d{1,3}(?=(\d{3})+$)/g, value => {
        return value + ',';
    });
};
console.log('2132141241'.millimeter()) // 2,132,141,241

检测数据类型

function toType(obj) {
    let class2type = {};
    ["Boolean", "Number", "String", "Function", "Array", "Date", "RegExp", "Object", "Error", "Symbol"].forEach(
        item => {
            class2type["[object " + item + "]"] = item.toLowerCase();
        });
    if (obj == null) return obj + "";
    return typeof obj === "object" || typeof obj === "function" ?
        class2type[class2type.toString.call(obj)] || "object" :
        typeof obj;
}
 
let obj = function () {};
console.log(toType(obj))

 

 

 

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