Iview DatePicker 之前月份禁用&& 下月可用

<template>
    <Row>
        <Col span="12">
            <DatePicker type="date" :options="options3" placeholder="Select date" style="width: 200px"></DatePicker>
        </Col>
        <Col span="12">
            <DatePicker type="month" :options="options4" placeholder="Select date" style="width: 200px"></DatePicker>
        </Col>
    </Row>
</template>
<script>
    export default {
        data () {
            return {
                options3: {
                    disabledDate (date) {
                        return date && date.valueOf() < Date.now() - 86400000;
                    }
                },
                options4: {
                    disabledDate (date) {                     
                        var dateNow = new Date() ;
                        return date && date.valueOf() < dateNow.setMonth(dateNow.getMonth()-1);
                    }
                }
            }
        }
    }
</script>

 <!-- 審批 -->
        <Modal
            v-model="modalApprove"       
            :closable="false"
            width="200px"
            @on-ok="approveSubmit"
            @on-cancel="approveCancel">
            <Form>
                <FormItem label="可乘車月份:"> 
                   <DatePicker 
                        type="month"  
                        :value="approveNextMonth"  
                        :options="optionsMonthOnly"                              
                        style="width:150px"                         
                        clearable 
                        placeholder="請選擇日期"
                    />                   
                </FormItem>
            </Form>        
        </Modal>

<script>
  //下月可用
                optionsMonthOnly:{
                    disabledDate (date) {                      
                        var dateNow = new Date() ;
                        return date && date.valueOf() < dateNow.setMonth(dateNow.getMonth())|| date.valueOf() > dateNow.setMonth(dateNow.getMonth()+1);
                    }
                },  </script>