elementUI（datepicker）限制日日期的选择

<div id="app">
        <div class="block">
            <span class="demonstration">起始日期</span>
            <el-date-picker v-model="startDate" type="date" placeholder="选择日期" :picker-options="pickerOptionsStart"
                @change="changeEnd">
            </el-date-picker>
        </div>
        <div class="block">
            <span class="demonstration">截止日期</span>
            <el-date-picker v-model="endDate" type="date" placeholder="选择日期" :picker-options="pickerOptionsEnd"
                @change="changeStart">
            </el-date-picker>
        </div>
    </div>

<script>
    new Vue({
        el: '#app',
        data() {
            return {
                pickerOptionsStart: {},
                pickerOptionsEnd: {},
                startDate: '',
                endDate: '',
            };
        },
        methods: {
            changeStart() {
                // 赋值
                this.pickerOptionsStart = Object.assign({}, this.pickerOptionsStart, {
                    disabledDate: (time) => {
                        return time.getTime() > this.endDate
                    }
                })
            },
            changeEnd() {
                this.pickerOptionsEnd = Object.assign({}, this.pickerOptionsEnd, {
                    disabledDate: (time) => {
                        return time.getTime() < this.startDate
                    }
                })
            }
        }
    })
</script>