JavaScript String 對象的實際運用

菜鳥教程

手機號碼隱藏中間四位

<p>{{hidePhoneNum}}</p>
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computed: {
  hidePhoneNum() {
    var phoneNum = this.$store.state.base.userInfo.phoneNum; //'18666667017'
    return [phoneNum.substr(0, 3), '****', phoneNum.substr(-4, 4)].join(''); //'186****7017'
  }
},
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找到網址倒數第二個'/'後的用戶名

//let href = 'http://www.baidu.com/2018/07/16/moonsic#/data'
let href = window.location.href;
let hrefArray = href.split('/');
let uid = hrefArray[hrefArray.length-2].slice(0,-1);
this.id = uid;
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去掉日期中的兩個'-'

let date = '2018-07-16';
let newDate = date.replace(/-/g, "");
this.date = newDate;
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限制字數，超出部分用省略號'...'

{{ word | limitWordCount(22) }}

filters:{
    limitWordCount(val,num){
        return val.length>num?val.substring(0,num)+'...':val;
    }
}
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報錯: Cannot read property 'substr' of undefined

先判斷是否爲字符串：

if(typeof value == 'string'){
    return substr(0,10)
}
if(typeof value != 'undefined'){
    return value.substr(0,10);
}
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在本例中，咱們經過 prototype 爲 JavaScript 的 String 對象添加方法，來實現將全部 "http" 替換爲 "https"：

String.prototype.replaceAll = function(search, replacement) {
    var target = this;
    return target.replace(new RegExp(search, 'g'), replacement);
};

var n=str.replaceAll("http","https");
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