A brief analysis of the role of slots and named slots in Vue

I believe that everyone who has used Vue has used the slot in

Vue more or less, but do you understand its usage? This article will bring you the basic use of slots and named slots in Vue. I hope it will be helpful to you!

1. Slot

1.1. The function of slot

⭐⭐
First introduction to slots:

• In order to make this component more versatile, we cannot limit the content in the component to fixed div, spanWait for these elements; [Related recommendations: vuejs video tutorial]
• For example, in a certain situation, we use a component and hope that the component displays a button. In this case, what we use the component to display is a picture;
• We should allow the user to decide what content and elements are stored in a certain area;
• So we can use slots to To solve this problem

In other words, if we want to add new content to a component tag, then we need to declare a slot in the component, otherwise, the added New content will not be rendered

⭐⭐
Using slots:

• Use slot elements as slots
• What content is inserted depends on how the parent element uses it. For example, if the parent component inserts a button or a picture, the button picture will be displayed. If not, it will not be displayed or the default content of the slot will be displayed.
• Sometimes we hope When using the slot, if the corresponding content is not inserted, then we need to display a default content:
• Of course, this default content will only be displayed when no inserted content is provided;
• We can set a default content in the slot tag

Use slot case:

Parent component

App.vue

<template>
    <div class="app">
        <!-- 内容是button -->
        <show-message title="哈哈哈">
            <button>我是按钮元素</button>
        </show-message>
        <!-- 内容是超链接 -->
        <show-message>
            <a href="#">百度一下</a>
        </show-message>

        <!-- 没有值传递 -->
        <show-message></show-message>
    </div>
</template>

Subcomponent
showMessage.vue

<template>
    <h2>{{title}}</h2>
    <div class="content">
        <slot>
            <p>我是默认值</p>
        </slot>
    </div>
</template>

• Rendering:
  
  We It can be found that in component showMessage, we give it a slot,
• in App.vue, we reuse showMessage three times ,
• once for button , once for a label , once without adding anything
• and the result is , one is the button , one is a link , is the default p label of the slot
  

##We can see that

What content the slot wants to display is determined by the parent element. If nothing is inserted into the slot, then the slot will be ignored
• In other words, if slots are used, if the parent element uses buttons, the child elements will display buttons, and if the parent element uses titles, the child elements will display titles.
• If the child component does not have a slot, then It cannot be displayed

1.2. Named slot Slot

⭐⭐

The desired effect is to display the corresponding content of the slot. At this time we can Use named slots:

Named slots, as the name implies, give the slot a name. The
• slot element has a special attribute: name;
A
• slot without name will have an implicit name default;
In other words, we can Give each slot a name. When
• is used in the parent component, it needs to be wrapped with a
• template tag and used ## in template #v-solt: Slot name named slot abbreviation
#Parent component

App.vue
<pre class="brush:js;toolbar:false;">&lt;template&gt; &lt;nav-bar&gt; &lt;template v-slot:left&gt; &lt;button&gt;返回&lt;/button&gt; &lt;/template&gt; &lt;template v-slot:center&gt; &lt;span&gt;内容&lt;/span&gt; &lt;/template&gt; &lt;template v-slot:right&gt; &lt;a href=&quot;#&quot;&gt;登录&lt;/a&gt; &lt;/template&gt; &lt;/nav-bar&gt; &lt;/template&gt;</pre>Subcomponent

NavBar.vue
(You can adjust the color in the css, so I won’t put it here)

<template>
    <div class="nav-bar">
        <div class="left">
            <slot name="left">left</slot>
        </div>
        <div class="center">
            <slot name="center">center</slot>
        </div>
        <div class="right">
            <slot name="right">right</slot>
        </div>
    </div>
</template>

Rendering:

The effect achieved is the display corresponding to the slot So this is the role of the named slot

⭐⭐

Dynamic slot name

Pass
v-slot: [dynamicSlotName]
way to dynamically bind a name;Ps: There are also scope slots, which I don’t understand very well yet, so I won’t write them down~

（Learning video sharing :

Web front-end development

, Basic programming video)

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