const data = this.$commonUtil.deepClone(this.form)
时间: 2023-08-08 12:09:59 浏览: 55
这段代码的作用是深拷贝一个对象,将 `this.form` 对象的所有属性和属性值复制到一个新的对象 `data` 中,并且 `data` 与 `this.form` 完全独立,修改 `data` 不会影响 `this.form`,反之亦然。这个函数是使用了一个常用的 JavaScript 技巧——递归。递归指的是函数调用自身的技术,当遇到对象或数组等引用类型时,递归调用自身,将其子元素也进行递归复制。这样可以确保深拷贝的所有引用类型都是独立的。
相关问题
const milestoneData = this.$R.filter(this.$R.propEq('MILESTONE', String(PLANNED_MILESTONE)), this.batchdata)
The code you provided seems to be using the Ramda library in JavaScript. It filters an array called `batchdata` based on a specific condition using `filter()` and `propEq()` functions from Ramda.
Let's break down the code:
```javascript
const milestoneData = this.$R.filter(
this.$R.propEq('MILESTONE', String(PLANNED_MILESTONE)),
this.batchdata
);
```
Here's what each part does:
1. `this.$R.filter`: Calls the `filter()` function from the Ramda library. It filters an array based on a predicate function.
2. `this.$R.propEq('MILESTONE', String(PLANNED_MILESTONE))`: This is the predicate function used by `filter()`. It checks if the value of the 'MILESTONE' property in each element of `this.batchdata` is equal to the string representation of `PLANNED_MILESTONE`.
3. `this.batchdata`: The array that is being filtered.
The result of this code will be a new array called `milestoneData` that contains only the elements from `this.batchdata` that have a 'MILESTONE' property equal to the string representation of `PLANNED_MILESTONE`.
Please note that the usage of `this.$R` implies that `$R` is an instance of the Ramda library and it is accessible through `this` context.
let video = this.$refs.videoElement; video为空如何处理
如果 `this.$refs.videoElement` 返回为空,有几种可能的原因和解决方法:
1. 确保在模板中正确地设置了 `ref` 属性,并且与 `this.$refs` 中的引用名称一致。
```html
<template>
<div>
<video ref="videoElement"></video>
</div>
</template>
```
2. 确保在访问 `this.$refs.videoElement` 之前,已经渲染了包含该元素的组件。Vue 组件的生命周期钩子函数 `mounted` 是一个常用的地方,可以在其中访问 `$refs`。
```javascript
<script>
export default {
mounted() {
const video = this.$refs.videoElement;
if (video) {
// 在这里可以操作 video 元素
} else {
console.log("videoElement is not available");
}
}
}
</script>
```
3. 如果你是在条件渲染(`v-if`)的情况下使用 `ref`,则需要确保条件满足时才能访问 `$refs`。
```html
<template>
<div>
<div v-if="showVideo">
<video ref="videoElement"></video>
</div>
<button @click="showVideo = true">Show Video</button>
</div>
</template>
<script>
export default {
data() {
return {
showVideo: false
};
},
mounted() {
if (this.showVideo) {
const video = this.$refs.videoElement;
if (video) {
// 在这里可以操作 video 元素
} else {
console.log("videoElement is not available");
}
}
}
}
</script>
```
通过以上的处理,你应该能够正确地获取到 `this.$refs.videoElement`,并且进行后续的操作。