elementUI message源码里为什么 watch closed 去控制 visible,而不是直接改变visible
<template> <transition name="el-message-fade" @after-leave="handleAfterLeave">
<div
:class="[
'el-message',
type && !iconClass ? `el-message--${ type }` : '',
center ? 'is-center' : '',
showClose ? 'is-closable' : '',
customClass
]"
:style="positionStyle"
v-show="visible"
@mouseenter="clearTimer"
@mouseleave="startTimer"
role="alert">
<i :class="iconClass" v-if="iconClass"></i>
<i :class="typeClass" v-else></i>
<slot>
<p v-if="!dangerouslyUseHTMLString" class="el-message__content">{{ message }}</p>
<p v-else v-html="message" class="el-message__content"></p>
</slot>
<i v-if="showClose" class="el-message__closeBtn el-icon-close" @click="close"></i>
</div>
</transition>
</template>
<script type="text/babel">
const typeMap = {
success: 'success',
info: 'info',
warning: 'warning',
error: 'error'
};
export default {
data() {
return {
visible: false,
message: '',
duration: 3000,
type: 'info',
iconClass: '',
customClass: '',
onClose: null,
showClose: false,
closed: false,
verticalOffset: 20,
timer: null,
dangerouslyUseHTMLString: false,
center: false
};
},
computed: {
typeClass() {
return this.type && !this.iconClass
? `el-message__icon el-icon-${ typeMap[this.type] }`
: '';
},
positionStyle() {
return {
'top': `${ this.verticalOffset }px`
};
}
},
watch: {
closed(newVal) {
if (newVal) {
this.visible = false;
}
}
},
methods: {
handleAfterLeave() {
this.$destroy(true);
this.$el.parentNode.removeChild(this.$el);
},
close() {
this.closed = true;
if (typeof this.onClose === 'function') {
this.onClose(this);
}
},
clearTimer() {
clearTimeout(this.timer);
},
startTimer() {
if (this.duration > 0) {
this.timer = setTimeout(() => {
if (!this.closed) {
this.close();
}
}, this.duration);
}
},
keydown(e) {
if (e.keyCode === 27) { // esc关闭消息
if (!this.closed) {
this.close();
}
}
}
},
mounted() {
this.startTimer();
document.addEventListener('keydown', this.keydown);
},
beforeDestroy() {
document.removeEventListener('keydown', this.keydown);
}
};
</script>
回答:
当然可以啊……只是人家开发者的个人选择而已,又不是啥范式。
实际上 this.closed = true
后面紧跟一句 this.visible = false
也不是不行。
除非说 this.closed = true
有很多处,为了避免重复代码、或者遗漏某些没写,可以提取到 Watch 里;但现在看起来只有一处,提不提取吧都行,爱咋写咋写。
P.S. Element-UI 的代码质量其实并不高,没必要学它的写法……
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