js工具方法

1. 回到顶部
   较为平滑的回到顶部方案

const scrollToTop = () => {
const c = document.documentElement.scrollTop || document.body.scrollTop;
if (c > 0) {
window.requestAnimationFrame(scrollToTop);
window.scrollTo(0, c - c / 8);
}
};
scrollToTop();
2. 删除数组指定项
项目中经常会使用的工具方法，传入目标数组和目标元素，返回一个新数组。

const removeArray = (arr, item) => {
let result = [];
let index = -1;
if (!(arr != null && arr.length)) {
return result;
}
result = arr;
if (Object.prototype.toString.call(item) == “[object Object]”) {
index = arr.findIndex((i) => isEqualObject(i, item));
} else {
index = arr.findIndex((i) => i === item);
}
if (index > -1) result.splice(index, 1);
return result;
};

const isEqualObject = (obja, objb) => {
const aProps = Object.getOwnPropertyNames(obja);
const bProps = Object.getOwnPropertyNames(objb);
if (aProps.length != bProps.length) {
return false;
}
for (let i = 0; i < aProps.length; i++) {
let propName = aProps[i];
let propA = obja[propName];
let propB = objb[propName];
if (!objb.hasOwnProperty(propName)) return false;
if (propA instanceof Object) {
if (!this.isEqualObject(propA, propB)) {
return false;
}
} else if (propA !== propB) {
return false;
}
}
return true;
};

removeArray([{ name: 1 }, { name: “1” }, 1, “1”], { name: “1” });
3. 获取 url 某一个参数
用于获取url传参获取参数

const getUrlParam = (key) => {
const url = new URL(window.location.href);
const value = url.searchParams.get(key);
return value;
};
getUrlParam(“id”);
4. 复制文本
复制各种自定义的文本，浏览器兼容性高

const copyText = (text) => {
const clipboardData = window.clipboardData;
if (clipboardData) {
clipboardData.clearData();
clipboardData.setData(“Text”, text);
return true;
} else if (document.execCommand) {
const el = document.createElement(“textarea”);
el.value = text;
el.setAttribute(“readonly”, “”);
el.style.position = “absolute”;
el.style.left = “-9999px”;
document.body.appendChild(el);
el.select();
document.execCommand(“copy”);
document.body.removeChild(el);
return true;
}
return false;
};
copyText(“Test”);
5. 禁止复制文本
body {
user-select: none;
-moz-user-select: none;
-webkit-user-select: none;
-ms-user-select: none;
}
// 禁止右键菜单
document.body.oncontextmenu = (e) => {
return false;
};
// 禁止选中文字
document.body.onselectstart = (e) => {
return false;
};
// 禁止复制
document.body.oncopy = (e) => {
return false;
};
// 禁止剪切
document.body.oncut = (e) => {
return false;
};
// 禁止粘贴
document.body.onpaste = (e) => {
return false;
};
6. 复制文本带版权信息
document.body.oncopy = (event) => {
event.preventDefault();
const clipboardData = event.clipboardData;
let text = window.getSelection(0).toString();
text = ${text}\n这是插入的文本\n 作者：于五五\n;
if (clipboardData) {
clipboardData.clearData();
clipboardData.setData(“Text”, text);
return true;
} else if (document.execCommand) {
window.clipboardData.setData(“Text”, text);
}
return false;
};
7. 判断数据类型和数据值
很常用的工具类，用于校验数据是否合法

// 是否是字符串
function isString(obj) {
return Object.prototype.toString.call(obj) == “[object String]”;
}

// 是否是数字
function isNumber(obj) {
return (
Object.prototype.toString.call(obj) == “[object Number]” &&
/[\d.]+/.test(String(obj))
);
}

// 是否是布尔
function isBoolean(obj) {
return Object.prototype.toString.call(obj) == “[object Boolean]”;
}

// 是否是数组
function isArray(obj) {
return Object.prototype.toString.call(obj) === “[object Array]”;
}

// 是否是对象
function isObject(arg) {
if (arg == null) {
return false;
} else {
return Object.prototype.toString.call(arg) == “[object Object]”;
}
}

// 是否是方法
function isFunction(arg) {
const type = Object.prototype.toString.call(arg);
return type == “[object Function]” || type == “[object AsyncFunction]”;
}

// 是否是时间格式
function isDate(obj) {
return Object.prototype.toString.call(obj) == “[object Date]”;
}

// 是否是时间undefined
function isUndefined(arg) {
return arg === void 0;
}

// 是否是空对象
function isEmptyObject(arg) {
if (isObject(arg)) {
for (var key in arg) {
if (Object.prototype.hasOwnProperty.call(arg, key)) {
return false;
}
}
return true;
}
return false;
}
8. ua 环境判断
用来区分不同平台，常用在ios端做适配

const getUaInfo = () => {
const ua = navigator.userAgent.toLowerCase();
const Agents = [
“Android”,
“android”,
“iPhone”,
“SymbianOS”,
“Windows Phone”,
“iPad”,
“iPod”,
];
let isPc = true;
for (var i = 0; i < Agents.length; i++) {
if (userAgentInfo.includes(Agents[i])) {
isPc = false;
break;
}
}
return {
// 是不是ios
isIos:
!!ua.match(/(i[^;]+;( U;)? CPU.+Mac OS X/) || ua.includes(“mac os x”),
// 是不是安卓
isAndroid:
ua.includes(“android”) || ua.includes(“Android”) || ua.includes(“Adr”),
// 是不是微信环境
isWeixin: ua.match(/MicroMessenger/i) == “micromessenger”,
// 是不是电脑端
isPc: isPc,
};
};
9. 时间格式转换
// Date转yyyy-MM-dd HH:mm:ss
const filterTimeByDate = (date, pattern = “yyyy-MM-dd HH:mm:ss”) => {
const o = {
“M+”: date.getMonth() + 1,
“d+”: date.getDate(),
“H+”: date.getHours(),
“m+”: date.getMinutes(),
“s+”: date.getSeconds(),
“q+”: Math.floor((date.getMonth() + 3) / 3),
S: date.getMilliseconds(),
};
if (/(y+)/.test(pattern)) {
pattern = pattern.replace(
RegExp.$1,
(date.getFullYear() + “”).substr(4 - RegExp.$1.length)
);
}
for (var k in o) {
if (new RegExp(“(” + k + “)”).test(pattern)) {
pattern = pattern.replace(
RegExp.$1,
RegExp.$1.length == 1 ? o[k] : (“00” + o[k]).substr((“” + o[k]).length)
);
}
}
return pattern;
};
filterTimeByDate(new Date());

// 时间戳转yyyy-MM-dd HH:mm:ss
const timestampToTime = (timestamp) => {
const date = new Date(
String(timestamp).length > 10 ? timestamp : timestamp * 1000
); //时间戳为10位需*1000，时间戳为13位的话不需乘1000
const Y = date.getFullYear() + “-”;
const M =
(date.getMonth() + 1 < 10
? “0” + (date.getMonth() + 1)
: date.getMonth() + 1) + “-”;
const D = (date.getDate() < 10 ? “0” + date.getDate() : date.getDate()) + " ";
const h =
(date.getHours() < 10 ? “0” + date.getHours() : date.getHours()) + “:”;
const m =
(date.getMinutes() < 10 ? “0” + date.getMinutes() : date.getMinutes()) +
“:”;
const s =
date.getSeconds() < 10 ? “0” + date.getSeconds() : date.getSeconds();
return Y + M + D + h + m + s;
};
timestampToTime(new Date().getTime());

// yyyy-MM-dd HH:mm:ss转时间戳
const timeToTimestamp = (time, isMilli = true) => {
const timestamp = new Date(time).getTime(); //时间戳为10位需*1000，时间戳为13位的话不需乘1000
return isMilli ? timestamp : timestamp / 1000;
};
timeToTimestamp(“2022-04-26 10:11:11”);
10. 函数防抖
const debounce = (fn, delay) => {
let timer = null;
return function (e) {
clearTimeout(timer);
timer = setTimeout(() => {
fn.apply(this, arguments);
}, delay);
};
};
document.addEventListener(
“scroll”,
debounce(function () {
console.log(“执行”);
}, 2000)
);
11. 全屏/退出全屏
function toFullScreen() {
let = document.documentElement;
el.webkitRequestFullScreen
? el.webkitRequestFullScreen()
: el.mozRequestFullScreen
? el.mozRequestFullScreen()
: el.msRequestFullscreen
? el.msRequestFullscreen()
: el.requestFullScreen
? el.requestFullScreen()
: alert(“当前浏览器不支持该功能”);
}

function exitFullscreen() {
let el = document;
el.webkitCancelFullScreen
? el.webkitCancelFullScreen()
: el.mozCancelFullScreen
? el.mozCancelFullScreen()
: el.cancelFullScreen
? el.cancelFullScreen()
: el.msExitFullscreen
? el.msExitFullscreen()
: el.exitFullscreen
? el.exitFullscreen()
: alert(“当前浏览器不支持该功能”);
}
12. 禁止打开控制台调试
用来防止部分用户通过源码攻击服务器，增加破解难度

setInterval(function () {
check();
}, 4000);
const check = () => {
function doCheck(a) {
if ((“” + a / a)[“length”] !== 1 || a % 20 === 0) {
(function () {}“constructor”());
} else {
(function () {}“constructor”());
}
doCheck(++a);
}
try {
doCheck(0);
} catch (err) {}
};
check();
13. 密码强度展示
const checkPwd = (str) => {
let Lv = 0;
if (str.length < 6) {
return Lv;
}
if (/[0-9]/.test(str)) {
Lv++;
}
if (/[a-z]/.test(str)) {
Lv++;
}
if (/[A-Z]/.test(str)) {
Lv++;
}
if (/[.|-|_]/.test(str)) {
Lv++;
}
return Lv;
};
14. 五星好评
const getRate = (rate = 0) => {
return “★★★★★☆☆☆☆☆”.slice(5 - rate, 10 - rate);
};
getRate(3);
15. 保留 n 位小数
const filterToFixed => (num, n = 2) {
return parseFloat(num.toFixed(n), 10);
}
16. 金额转大写
商城项目里订单模块很常用的工具方法

const convertCurrency = (money) => {
//汉字的数字
const cnNums = new Array(
“零”,
“壹”,
“贰”,
“叁”,
“肆”,
“伍”,
“陆”,
“柒”,
“捌”,
“玖”
);
//基本单位
const cnIntRadice = new Array(“”, “拾”, “佰”, “仟”);
//对应整数部分扩展单位
const cnIntUnits = new Array(“”, “万”, “亿”, “兆”);
//对应小数部分单位
const cnDecUnits = new Array(“角”, “分”, “毫”, “厘”);
//整数金额时后面跟的字符
const cnInteger = “整”;
//整型完以后的单位
const cnIntLast = “元”;
//最大处理的数字
const maxNum = 999999999999999.9999;
//金额整数部分
let integerNum;
//金额小数部分
let decimalNum;
//输出的中文金额字符串
let chineseStr = “”;
//分离金额后用的数组，预定义
let parts;
// 传入的参数为空情况
if (money == “”) {
return “”;
}
money = parseFloat(money);
if (money >= maxNum) {
return “”;
}
// 传入的参数为0情况
if (money == 0) {
chineseStr = cnNums[0] + cnIntLast + cnInteger;
return chineseStr;
}
// 转为字符串
money = money.toString();
// indexOf 检测某字符在字符串中首次出现的位置 返回索引值（从0 开始） -1 代表无
if (money.indexOf(“.”) == -1) {
integerNum = money;
decimalNum = “”;
} else {
parts = money.split(“.”);
integerNum = parts[0];
decimalNum = parts[1].substr(0, 4);
}
//转换整数部分
if (parseInt(integerNum, 10) > 0) {
let zeroCount = 0;
let IntLen = integerNum.length;
for (let i = 0; i < IntLen; i++) {
let n = integerNum.substr(i, 1);
let p = IntLen - i - 1;
let q = p / 4;
let m = p % 4;
if (n == “0”) {
zeroCount++;
} else {
if (zeroCount > 0) {
chineseStr += cnNums[0];
}
zeroCount = 0;
chineseStr += cnNums[parseInt(n)] + cnIntRadice[m];
}
if (m == 0 && zeroCount < 4) {
chineseStr += cnIntUnits[q];
}
}
// 最后+ 元
chineseStr += cnIntLast;
}
// 转换小数部分
if (decimalNum != “”) {
let decLen = decimalNum.length;
for (let i = 0; i < decLen; i++) {
let n = decimalNum.substr(i, 1);
if (n != “0”) {
chineseStr += cnNums[Number(n)] + cnDecUnits[i];
}
}
}
if (chineseStr == “”) {
chineseStr += cnNums[0] + cnIntLast + cnInteger;
} else if (decimalNum == “”) {
chineseStr += cnInteger;
}

return chineseStr;
};
17. 常用正则判断
// 校验昵称为2-9位中文
const validateName = (name) => {
const reg = /¹{2,9}$/;
return reg.test(name);
};

// 校验手机号
const validateMobile = (mobile) => {
const reg = /^1[3,4,5,6,7,8,9]\d{9}$/;
return reg.test(mobile);
};

// 校验6到18位大小写字母数字下划线组成的密码
const validatePassword = (password) => {
const reg = /²{6,18}$/;
return reg.test(password);
};

// 校验身份证号
const validateCardId = (cardId) => {
const reg = /(^{\d{15}$)|(^\d{18}$)|(}\d{17}(\d|X|x)$)/;
return reg.test(cardId);
};
18. 解决运算精度丢失的问题
用来解决前端计算金额时精度丢失的问题

const calculation = {
// 加法
plus(arg1, arg2) {
var r1, r2, m;
try {
r1 = arg1.toString().split(“.”)[1].length;
} catch (e) {
r1 = 0;
}
try {
r2 = arg2.toString().split(“.”)[1].length;
} catch (e) {
r2 = 0;
}
m = Math.pow(10, Math.max(r1, r2));
return (arg1 * m + arg2 * m) / m;
},
//减法
subtract(arg1, arg2) {
var r1, r2, m, n;
try {
r1 = arg1.toString().split(“.”)[1].length;
} catch (e) {
r1 = 0;
}
try {
r2 = arg2.toString().split(“.”)[1].length;
} catch (e) {
r2 = 0;
}
m = Math.pow(10, Math.max(r1, r2));
n = r1 >= r2 ? r1 : r2;
return ((arg1 * m - arg2 * m) / m).toFixed(n);
},
// 乘法
multiply(arg1, arg2) {
var m = 0,
s1 = arg1.toString(),
s2 = arg2.toString();
try {
m += s1.split(“.”)[1].length;
} catch (e) {}
try {
m += s2.split(“.”)[1].length;
} catch (e) {}
return (
(Number(s1.replace(“.”, “”)) * Number(s2.replace(“.”, “”))) /
Math.pow(10, m)
);
},
// 除法
divide(arg1, arg2) {
var t1 = 0,
t2 = 0,
r1,
r2;
try {
t1 = arg1.toString().split(“.”)[1].length;
} catch (e) {}
try {
t2 = arg2.toString().split(“.”)[1].length;
} catch (e) {}
r1 = Number(arg1.toString().replace(“.”, “”));
r2 = Number(arg2.toString().replace(“.”, “”));
return (r1 / r2) * Math.pow(10, t2 - t1);
},
};