JS对象常用扩展方法

string对象

1.去除空格和指定字符串等

/*
* 以某字符串开头判断
*注意:参数str中如果包含正则通配字符,如"."请改参数为"\\."
*/
String.prototype.startWith = function (str) {
    var reg = new RegExp("^" + str);
    return reg.test(this);
}

/*
* 以某字符串结尾判断
*注意:参数str中如果包含正则通配字符,如"."请改参数为"\\."
*/
String.prototype.endWith = function (str) {
    var reg = new RegExp(str + "$");
    return reg.test(this);
}

/*
*字符串去除两侧空格或指定字符
*注意:参数str中如果包含正则通配字符,如"."请改参数为"\\."
*/
String.prototype.trimAll = function (str) {//js1.8版本以上自带trim,这里改名强烈建议不重复构写方法
    str = (str ? str : "\\s");
    str = ("(" + str + ")");
    var reg_trim = new RegExp("(^" + str + "*)|(" + str + "*$)", "g");
    return this.replace(reg_trim, "");
};

/*
*字符串去除左侧空格或指定字符
*注意:参数str中如果包含正则通配字符,如"."请改参数为"\\."
*/
String.prototype.trimLeft = function (str) {
    str = (str ? str : "\\s");                            //没有传入参数的，默认去空格
    str = ("(" + str + ")");
    var reg_lTrim = new RegExp("^" + str + "*", "g");     //拼正则
    return this.replace(reg_lTrim, "");
}

/*
*字符串去除右侧空格或指定字符
*注意:参数str中如果包含正则通配字符,如"."请改参数为"\\."
*/
String.prototype.trimRight = function (str) {
    str = (str ? str : "\\s");
    str = ("(" + str + ")");
    var reg_rTrim = new RegExp(str + "*$", "g");
    return this.replace(reg_rTrim, "");
}

/*
*字符串是否包含某字符串
*/
String.prototype.contains = function (str) {//利用indexof  
    //值为位置,为-1说明不包含  
    if (this.indexOf(str) >= 0) return true;
    else return false;
};

/*
*字符串是否是大于0的整数或小数
*/
String.prototype.isPositiveDecimal = function () {
    var reg = /^((0\.\d*[1-9])|([1-9]\d*(\.\d*[1-9])?))$/;
    return reg.test(this);
}

2.是否包含contains

        String.prototype.contains = function (str) {//利用indexof
            //值为位置,为-1说明不包含
            if (this.indexOf(str) >= 0) return true;
            else return false;
        };

        String.prototype.contains = function (str) {//利用正则表达式
            var reg = new RegExp(str);
            return reg.test(this);
        };

Array对象

1.是否包含某元素

JQuery已有 $.inArray(str, arr); 来判断

如果非要写扩展方法

  Array.prototype.contains = function(item){
    for(i=0;i<this.length;i++){
        if(this[i]==item){return true;}
    }
    return false;
};

下面是常用扩展方法集合

<script type="text/javascript">
        //获取字符数组
        String.prototype.toCharArray = function () {
            return this.split("");
        }
        //获取N个相同的字符串
        String.prototype.repeat = function (num) {
            var tmpArr = [];
            for (var i = 0; i < num; i++) {
                temArr.push(this);
                return temArr.join("");
            }
        }
        //逆序
        String.prototype.reverse = function () {
            return this.split("").reverse().join("");

        }
        //测试是否是数字
        String.prototype.isNumeric = function () {
            var tmpFloat = parseFloat(this);
            if (isNaN(tmpFloat))
                return false;
            var tmpLen = this.length - tmpFloat.toString().length;
            return tmpFloat + "0".Repeat(tmpLen) == this;
        }
        //测试是否是整数
        String.prototype.isInt = function () {
            if (this == "NaN")
                return false;
            return this == parseInt(this).toString();
        }
        // 合并多个空白为一个空白
        String.prototype.resetBlank = function () {
            return this.replace(/s+/g, " ");
        }
        // 除去左边空白
        String.prototype.LTrim = function () {
            return this.replace(/^s+/g, "");
        }
        // 除去右边空白
        String.prototype.RTrim = function () {
            return this.replace(/s+$/g, "");
        }
        // 除去两边空白
        String.prototype.trim = function () {
            return this.replace(/(^s+)|(s+$)/g, "");
        }
        // 保留数字
        String.prototype.getNum = function () {
            return this.replace(/[^d]/g, "");
        }
        // 保留字母
        String.prototype.getEn = function () {
            return this.replace(/[^A-Za-z]/g, "");
        }
        // 保留中文
        String.prototype.getCn = function () {
            return this.replace(/[^u4e00-u9fa5uf900-ufa2d]/g, "");
        }
        // 得到字节长度
        String.prototype.getRealLength = function () {
            return this.replace(/[^x00-xff]/g, "--").length;
        }
        // 从左截取指定长度的字串
        String.prototype.left = function (n) {
            return this.slice(0, n);
        }
        // 从右截取指定长度的字串
        String.prototype.right = function (n) {
            return this.slice(this.length - n);
        }
        // HTML编码
        String.prototype.HTMLEncode = function () {
            var re = this;
            var q1 = [/x26/g, /x3C/g, /x3E/g, /x20/g];
            var q2 = ["&", "<", ">", " "];
            for (var i = 0; i < q1.length; i++)
                re = re.replace(q1[i], q2[i]);
            return re;
        }
        // Unicode转化
        String.prototype.ascW = function () {
            var strText = "";
            for (var i = 0; i < this.length; i++)
                strText += "&#" + this.charCodeAt(i) + ";";
            return strText;
        }
        // 获取文件全名
        String.prototype.GetFileName = function () {
            var regEx = /^.*\/([^\/\?]*).*$/;
            return this.replace(regEx, '$1');
        };
        // 获取文件扩展名
        String.prototype.GetExtensionName = function () {
            var regEx = /^.*\/[^\/]*(\.[^\.\?]*).*$/;
            return this.replace(regEx, '$1');
        };
        //替换所有
        String.prototype.replaceAll = function (reallyDo, replaceWith, ignoreCase) {
            if (!RegExp.prototype.isPrototypeOf(reallyDo)) {
                return this.replace(new RegExp(reallyDo, (ignoreCase ? "gi" : "g")), replaceWith);
            } else {
                return this.replace(reallyDo, replaceWith);
            }
        };
        //格式化字符串
        String.prototype.Format = function () {
            if (arguments.length == 0) {
                return '';
            }
            if (arguments.length == 1) {
                return arguments[0];
            }
            var reg = /{(\d+)?}/g;
            var args = arguments;
            var result = arguments[0].replace(reg, function ($0, $1) {
                return args[parseInt($1) + 1];
            });
            return result;
        };

        // 数字补零
        Number.prototype.LenWithZero = function (oCount) {
            var strText = this.toString();
            while (strText.length < oCount) {
                strText = '0' + strText;
            }
            return strText;
        };
        // Unicode还原
        Number.prototype.ChrW = function () {
            return String.fromCharCode(this);
        };


        // 数字数组由小到大排序
        Array.prototype.Min2Max = function () {
            var oValue;
            for (var i = 0; i < this.length; i++) {
                for (var j = 0; j <= i; j++) {
                    if (this[i] < this[j]) {
                        oValue = this[i];
                        this[i] = this[j];
                        this[j] = oValue;
                    }
                }
            }
            return this;
        };

        // 数字数组由大到小排序
        Array.prototype.Max2Min = function () {
            var oValue;
            for (var i = 0; i < this.length; i++) {
                for (var j = 0; j <= i; j++) {
                    if (this[i] > this[j]) {
                        oValue = this[i];
                        this[i] = this[j];
                        this[j] = oValue;
                    }
                }
            }
            return this;
        };

        // 获得数字数组中最大项
        Array.prototype.GetMax = function () {
            var oValue = 0;
            for (var i = 0; i < this.length; i++) {
                if (this[i] > oValue) {
                    oValue = this[i];
                }
            }
            return oValue;
        };

        // 获得数字数组中最小项
        Array.prototype.GetMin = function () {
            var oValue = 0;
            for (var i = 0; i < this.length; i++) {
                if (this[i] < oValue) {
                    oValue = this[i];
                }
            }
            return oValue;
        };

        Array.prototype.add = function (item) {
            this.push(item);
        }
        Array.prototype.addRange = function (items) {
            var length = items.length;
            if (length != 0) {
                for (var index = 0; index < length; index++) {
                    this.push(items[index]);

                }
            }
        }
        Array.prototype.clear = function () {
            if (this.length > 0) {
                this.splice(0, this.length);
            }
        }
        Array.prototype.isEmpty = function () {
            if (this.length == 0) {
                return true;
            }
            else {
                return false;
            }
        }
        Array.prototype.clone = function () {
            var clonedArray = [];
            var length = this.length;
            for (var index = 0; index < length; index++) {
                clonedArray[index] = this[index];
            }
            return clonedArray;
        }
        Array.prototype.contains = function (item) {
            var index = this.indexOf(item);
            return (index >= 0);
        }
        Array.prototype.dequeue = function () {
            return this.shift();
        }
        Array.prototype.indexOf = function (item) {
            var length = this.length;

            if (length != 0) {
                for (var index = 0; index < length; index++) {
                    if (this[index] == item) {
                        return index;
                    }
                }
            }
            return -1;
        }
        Array.prototype.insert = function (index, item) {
            this.splice(index, 0, item);
        }
        Array.prototype.joinstr = function (str) {
            var newStr = new Array(this.length);
            for (var i = 0; i < this.length; i++) {
                newStr[i] = this[i] + str;
            }
            return newStr;
        }
        Array.prototype.queue = function (item) {//入队
            this.push(item);
        }
        Array.prototype.remove = function (item) {
            var index = this.indexOf(item);
            if (index >= 0) {
                this.splice(index, 1);
            }
        }
        Array.prototype.removeAt = function (index) {
            this.splice(index, 1);
        }
        //给js原生Array增加each方法
        Array.prototype.each = function (fn) {
            return this.length ? [fn(this.slice(0, 1))].concat(this.slice(1).each(fn)) : [];
        };

        // 获取当前时间的中文形式
        Date.prototype.GetCNDate = function () {
            var oDateText = '';
            oDateText += this.getFullYear().LenWithZero(4) + new Number(24180).ChrW();
            oDateText += this.getMonth().LenWithZero(2) + new Number(26376).ChrW();
            oDateText += this.getDate().LenWithZero(2) + new Number(26085).ChrW();
            oDateText += this.getHours().LenWithZero(2) + new Number(26102).ChrW();
            oDateText += this.getMinutes().LenWithZero(2) + new Number(20998).ChrW();
            oDateText += this.getSeconds().LenWithZero(2) + new Number(31186).ChrW();
            oDateText += new Number(32).ChrW() + new Number(32).ChrW() + new Number(26143).ChrW() + new Number(26399).ChrW() + new String('26085199682010819977222352011620845').substr(this.getDay() * 5, 5).ToInt().ChrW();
            return oDateText;
        };
        //扩展Date格式化
        Date.prototype.Format = function (format) {
            var o = {
                "M+": this.getMonth() + 1, //月份
                "d+": this.getDate(), //日
                "h+": this.getHours() % 12 == 0 ? 12 : this.getHours() % 12, //小时
                "H+": this.getHours(), //小时
                "m+": this.getMinutes(), //分
                "s+": this.getSeconds(), //秒
                "q+": Math.floor((this.getMonth() + 3) / 3), //季度
                "S": this.getMilliseconds() //毫秒
            };
            var week = {
                "0": "\u65e5",
                "1": "\u4e00",
                "2": "\u4e8c",
                "3": "\u4e09",
                "4": "\u56db",
                "5": "\u4e94",
                "6": "\u516d"
            };
            if (/(y+)/.test(format)) {
                format = format.replace(RegExp.$1, (this.getFullYear() + "").substr(4 - RegExp.$1.length));
            }
            if (/(E+)/.test(format)) {
                format = format.replace(RegExp.$1, ((RegExp.$1.length > 1) ? (RegExp.$1.length > 2 ? "\u661f\u671f" : "\u5468") : "") + week[this.getDay() + ""]);
            }
            for (var k in o) {
                if (new RegExp("(" + k + ")").test(format)) {
                    format = format.replace(RegExp.$1, (RegExp.$1.length == 1) ? (o[k]) : (("00" + o[k]).substr(("" + o[k]).length)));
                }
            }
            return format;
        }
        Date.prototype.Diff = function (interval, objDate) {
            //若参数不足或 objDate 不是日期类型則回传 undefined
            if (arguments.length < 2 || objDate.constructor != Date) { return undefined; }
            switch (interval) {
                //计算秒差
                case 's': return parseInt((objDate - this) / 1000);
                    //计算分差
                case 'n': return parseInt((objDate - this) / 60000);
                    //计算時差
                case 'h': return parseInt((objDate - this) / 3600000);
                    //计算日差
                case 'd': return parseInt((objDate - this) / 86400000);
                    //计算周差
                case 'w': return parseInt((objDate - this) / (86400000 * 7));
                    //计算月差
                case 'm': return (objDate.getMonth() + 1) + ((objDate.getFullYear() - this.getFullYear()) * 12) - (this.getMonth() + 1);
                    //计算年差
                case 'y': return objDate.getFullYear() - this.getFullYear();
                    //输入有误
                default: return undefined;
            }
        };

        //检测是否为空
        Object.prototype.IsNullOrEmpty = function () {
            var obj = this;
            var flag = false;
            if (obj == null || obj == undefined || typeof (obj) == 'undefined' || obj == '') {
                flag = true;
            } else if (typeof (obj) == 'string') {
                obj = obj.trim();
                if (obj == '') {//为空
                    flag = true;
                } else {//不为空
                    obj = obj.toUpperCase();
                    if (obj == 'NULL' || obj == 'UNDEFINED' || obj == '{}') {
                        flag = true;
                    }
                }
            }
            else {
                flag = false;
            }
            return flag;
        }
    </script>

来源：CSDN

作者：Nemo_XP

链接：https://blog.csdn.net/spw55381155/article/details/80193896