解决DateTimePicker 的 clear 属性设置为 false 时，不能隐藏弹出层中的 clear 按钮问题https://github.com/ElemeFE/element/pull/22990

[mole422]

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[cocogg28]

What is the principle behind your solution?

[mole422]

1. Introducing the v-if="clearable" directive in the component's template to ensure that the rendering of the clear button is contingent upon the truthiness of the clearable attribute.
2. Binding the picker.clearable property of the component instance to the passed clearable attribute to synchronize the internal state with the external property.
3. Utilizing Vue.js's $watch function to monitor changes to the clearable attribute, updating the picker object's clearable property in response to changes, thus ensuring the component remains responsive to external attribute modifications.

[cocogg28]

How this design ensures the responsiveness and state consistency of components

[mole422]

This design ensures component responsiveness and state consistency by using Vue.js's reactive features such as conditional rendering with v-if="clearable", property binding to synchronize internal state with external attributes, and $watch to monitor and react to changes in the clearable attribute, thereby keeping the UI and component state in sync.