前端实用小工具（URL参数截取、JSON判断、数据类型检测、版本号对比等）

背景

在日常开发中，我们经常会用一些工具类方法来实现业务逻辑 下面列举几种最常用的

URL截取参数

//直接调用输入想要截取的参数名称几个
export function getParamFromUrl(key) {
    if (key === undefined) return null;
    let search = location.search.substr(1);
    let mReg = new RegExp('(^|&)' + key + '=([^&]*)(&|$)');
    let mValue = search.match(mReg);
    if (mValue != null) return unescape(mValue[2]);
    return null;
}
//示例
let city = getParamFromUrl('city');

JSON是否为空判断

//输入想要检测的json数据 如果为空返回返回false
export function isNullObject(model) {
  if (typeof model === "object") {
    let hasProp = false;
    for (const prop in model) {
        hasProp = true;
        break;
    }
    if (hasProp) {
        return false;
    }
    return true;
  } else {
      throw "model is not object";
  }
}

数据类型检测

//检测变量的数据类型
export function getParamType(item) {
    if (item === null) return null;
    if (item === undefined) return undefined;
    return Object.prototype.toString.call(item).slice(8, -1);
}
//返回String Function Boolean Object Number

获取cookie

//获取document下cookie的具体某个参数值
export function getCookie(key) {
    if (key === undefined) {
        return undefined;
    }
    let cookies = document.cookie;
    let mReg = new RegExp('(^|;)\\s*' + key + '=([^;]*)(;|$)');
    let mValue = cookies.match(mReg);
    let ret = undefined;
    if (mValue != null) {
        ret = unescape(mValue[2]);
    }
    if (ret !== undefined) {
        ret = ret.replace(/^\"|\'/i, '').replace(/\"|\'$/i, '');
    }
    return ret;
}

版本号对比

一般在做APP端开发的时候需要用到一些版本控制，那么就需要针对版本号来进行对比，高版本或者低版本做一些特殊的逻辑处理，下面就是提供版本对比的方法

//传入要对比的版本号，一般前面一个传入当前的版本号，后面一个写上要对比的版本号
export function versionCompare(higher, lower) {
    let sep = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : '.';

    let higherAry = higher.split(sep),
        lowerAry = lower.split(sep);
    let l = Math.max(higherAry.length, lowerAry.length);
    for (let i = 0; i < l; i++) {
        let high = parseInt(higherAry[i] || 0);
        let low = parseInt(lowerAry[i] || 0);
        if (high > low) {
            return 1;
        }
        if (high < low) {
            return -1;
        }
    }
    return 0;
}
//返回值  higher > lower: 1;higher = lower: 0;higher < lower:-1

数组去重

export function arrayUniq(array){
    let temp = []; 
    for(var i = 0; i < array.length; i++){
        if(temp.indexOf(array[i]) == -1){
            temp.push(array[i]);
        }
    }
    return temp;
}

iPhone X系列机型判断

export function isIphoneX() {
    // iPhone X、iPhone XS
    var isIPhoneX =
        /iphone/gi.test(window.navigator.userAgent) &&
        window.devicePixelRatio &&
        window.devicePixelRatio === 3 &&
        window.screen.width === 375 &&
        window.screen.height === 812;
    // iPhone XS Max
    var isIPhoneXSMax =
        /iphone/gi.test(window.navigator.userAgent) &&
        window.devicePixelRatio &&
        window.devicePixelRatio === 3 &&
        window.screen.width === 414 &&
        window.screen.height === 896;
    // iPhone XR
    var isIPhoneXR =
        /iphone/gi.test(window.navigator.userAgent) &&
        window.devicePixelRatio &&
        window.devicePixelRatio === 2 &&
        window.screen.width === 414 &&
        window.screen.height === 896;
    if (isIPhoneX || isIPhoneXSMax || isIPhoneXR) {
        return true;
    }
    return false;
}