vue.js 驗證兩次密碼是否一致,不用validate,elementUI組件

<div class="retrieve_password" id="retrieve_password">
    <p>重置密碼</p>
    <p>設置密碼</p>
    <input type="password" placeholder="請輸入6~15位密碼" v-model.lazy="passwordModel"/>
    <span>@{{passwordValidate.errorText}}</span>
    <p>確認密碼</p>
    <input type="password" placeholder="請再輸入一遍密碼"  v-model.lazy="passwordcheckModel" />
    <span>@{{passwordCheckValidate.errorText}}</span>
    <button>下一步</button>
</div>

computed: {

    passwordValidate: function() {
        var errorText;
        if(!/^[0-9A-Za-z]{6,15}$/.test(this.passwordModel)) {
            errorText = '密碼少于6位'
        } else {
            errorText = ''
        }
        if(!this.passwordFlag) {
            errorText = ''
            this.passwordFlag = true
        }
        return {
            errorText
        }
    },
        passwordCheckValidate: function() {
        var errorText;
        if(!/^[0-9A-Za-z]{6,15}$/.test(this.passwordcheckModel)) {
            errorText = '密碼少于6位'
        }else if(this.passwordcheckModel !==this.passwordModel ){
            errorText = '兩次密碼不匹配'
        }
        else {
            errorText = ''
        }
        
        if(!this.passwordFlag) {
            errorText = ''
            this.passwordFlag = true
        }
        return {
            errorText
        }
    }
    
},