Initially, I am fetching data from api in the created hook which is perfectly working.
created() {
this.fetchInformation()
}
But I was having look over best practices for lifecycle hooks and I came to this line You need to fetch some data for your component on initialization. Use created (or created + activated for keep-alive components)
I also tried to look for relevant articles or information on the internet.
Url for reference - https://alligator.io/vuejs/component-lifecycle/
My component is rendering inside keep-alive so I tried this for the test purpose.
activated() {
this.fetchInformation()
}
Instead of created, now as expected everytime the component activates it execute the api call which is really cool. But I still want to understand what this actually created + activated as I am using activated or created but if I am correct just by reading that I should do them both.
Please let me know if anything else required to understand my question.
Thanks
Use correctly keep-alive!!
Incorrect:
<template>
<div>
<div v-if="canRender">
<keep-alive>
<my-component />
</keep-alive>
</div>
</div>
<template>
Incorrect:
<template>
<div>
<keep-alive>
<div v-if="canRender">
<my-component />
</div>
</keep-alive>
</div>
<template>
Correct:
<template>
<div>
<div>
<keep-alive>
<my-component v-if="canRender" />
</keep-alive>
</div>
</div>
<template>
Related
The Problem
Let's say we have a page template written as a Web component in a shared library to keep the company design system consistent. That page has some slots:
export class PageTemplate extends LitElement {
static properties = {
title: { type: String },
};
render() {
return html`
<div>
<h1>${title}</h1>
<slot name="template-body"></slot>
<div class="some-special-styles">
<slot name="template-buttons"></slot>
</div>
</div>
`;
}
}
customElements.define("page-template", PageTemplate);
Then we use this template in a Vue (v3.2.45) application on a base component to be used in the same app by multiple pages.
//page-base.vue
<template>
<page-template title="My App Name">
<slot name="base-body"></slot>
<slot name="base-buttons"></slot>
</page-template>
</template>
Here, we will use the page base vue component on a specific page.
//login-page.vue
<template>
<PageBase>
<template #base-body>
<div slot="template-body">
<input placeholder="some special code"/>
</div>
</template>
<template #base-buttons>
<button slot="template-buttons">login</button>
<button slot="template-buttons">back</button>
</template>
</PageBase>
</template>
To make the login page components show inside that original page template web component; we need to declare the slot property on the leaf components like in <button slot="template-buttons">
How can I implement the Vue Page Base component to avoid the need to remember to set the slot property in every leaf vue component?
Things I've Tryied
I've tried to solve this using the vanilla web syntax below, but Vue appears not to dispatch that information to the final HTML:
//page-base.vue
<template>
<page-template title="My App Name">
<!-- this does not work -->
<slot name="base-body" slot="template-body"></slot>
<slot name="base-buttons" slot="template-buttons"></slot>
</page-template>
</template>
There was also an attempt (after a suggestion in the comments) to use a template as a ghost intermediate in the page base. But nothing was rendered at runtime.
//page-base.vue
<template>
<page-template title="My App Name">
<!-- i can't have that span because of some-special-styles applied in the template-->
<template slot="template-body"><slot name="base-body"></slot></template>
<template slot="template-buttons"><slot name="base-buttons"></slot></template>
</page-template>
</template>
The approach to using some middle element to make the connection (like below) enables content rendering. Still, it does not work for the project requirements because, for style reasons, I need that the final components be the top-most nodes in the page template slots.
//page-base.vue
<template>
<page-template title="My App Name">
<!-- although it runs, i can't have these spans because of some-special-styles applied in the template -->
<span slot="template-body"><slot name="base-body"></slot></span>
<span slot="template-buttons"><slot name="base-buttons"></slot></span>
</page-template>
</template>
I just got started to Vue and i'm trying to understand some basic concepts such as conditional rendering and how to pass data from where i load the app to a component. Suppose i'm rendering a Vue component like this:
<div id="app">
<myComponent></myComponent>
</div>
Suppose myComponent looks like this:
<template>
<div>
<h1>First block</h1>
</h1>Second block</h1>
</div>
</template>
I want to be able to render First block or Second block when i load the Vue app according to a parameter i pass to the component, like:
<div id="app">
<myComponent id="first"></myComponent>
</div>
In this case i should see First block, whereas if instead of id="first" there was id="second" the output was supposed to be Second block. How can i do this?
I know it's a very basic question, but most of the sources i found explained how to do the opposite. Any kind of advice is appreciated!
In vue you could pass props (parameters) to component which defines this ones in its script like :
<template>
<div>
<h1 v-if="block==='first'">First block</h1>
</h1 v-else>Second block</h1>
</div>
</template>
<script>
export default{
props:{
block:{
type:String,
default:'first'
}
}
}
</script>
in parent component pass the prop like :
<div id="app">
<myComponent block="first"></myComponent>
</div>
or
<div id="app">
<myComponent block="second"></myComponent>
</div>
I have a global sidebar component TheSidebar.vue:
<template>
<aside>
<slot></slot>
</aside>
</template>
In Blogs.vue (a page component) I try to register two components.
<template>
<div>
<h1>Experiences</h1>
<TheSidebar>
<SearchBlog />
<CategoryCheckboxFilter />
</TheSidebar>
<ExperienceList />
</div>
</template>
It seems like I cannot register two components in a slot?
Is this a good setup anyway and who do I have to achieve this?
Update
It's just working fine now and I can register more than one component in a <slot />. I think some webpack building issue before.
I have input on custom component and when i click on the next button on the wrapper component i need to emit details to the parent component.
How is this possible in vue?
wrapper.vue
<template>
<div :id="contentId" class="mt-3">
<div>
<slot></slot>
</div>
<b-row class="float-right">
<b-col>
<button cssClass="e-outline" v-on:click="btnNext">{{nextButtonText}}</button>
</b-col>
</b-row>
</div>
</template>
parent.vue
<template>
<div>
<Wrapper contentId="1">
<CustomComponent1 />
</wrapper>
<Wrapper contentId="2">
<CustomComponent1 />
</wrapper>
</div>
</template>
customComponent1.vue
<template>
<div>
<input v-model="name" />
<input v-model="name2" />
</div>
</template>
code above is for illustrative purposes.
The problem is that the wrapper doesn't innately have access to data of the scoped component, therefore these links have to be created manually. There is no way to tell how many children or slots the component may have, so this kind of functionality is not part of the vue magic.
So in an example where you have parent App component, which holds a Wrapper that has a MyInput component in the slot...
MyInput
The MyInout component doesn't automatically update other components, so it needs to be setup to $emit the internal data.
This can be done using a watch, #change listener for the input, or some other way. You can emit multiple datum as they change, or use a single payload with all the data
this.$emit("input", myData);
App
The App needs to explicitly connect the data between MyInout and Wrapper
<Wrapper> <MyInput #input="onInput" slot-scope="{ onInput }" /> </Wrapper>
The magic/trick happens here, where we bind the input emit function of the input to the onInput function using slot-scope.
Wrapper
The wrapper then needs to listen to the events passed (via App) from Wrapper
<slot :onInput="onInput" />
where onInput is a method that would process the data
see example below
I would recommend the following reading
https://github.com/vuejs/vue/issues/4332 (specifically Evan's response why it's not possible)
https://adamwathan.me/renderless-components-in-vuejs/ Adam has a thoroughly documented way of using render functions and slots to abstract functionality from the UI. While it's not directly related, it's a worthwhile read and may provide more info on using slot-scope as well as some perspective on improving the structure of UI components.
I have a modal.vue component as follows:
<template>
<transition name="modal-transition">
<div class="modal-body" v-if="displayed">
<div class="modal-overlay" #click="displayed = false"></div>
<div class="modal-content">
<slot/>
</div>
</div>
</transition>
</template>
How do I mount this component to the applications root element rather than in place?
For crude inaccurate example:
<body>
<div id="app">
<div class="header"></div>
<div class="nav"></div>
<div class="stage">
<div class="sub-nav"></div>
<div class="content">
<modal :display.sync="display">MY MODAL</modal> <-- Don't mount here...
</div>
</div>
<-- Mount here instead...
</div>
</body>
The current issue is that my sites header and navigation is layered on top of my modal and it's darkened full screen overlay instead of layered behind the modal overlay.
Update for Vue 3
There is now a built in feature called teleport which allows mounting parts of your component template to any DOM element.
The example from the OP would look like something like this
<!-- MyModal.vue -->
<template>
<transition name="modal-transition">
<div class="modal-body" v-if="displayed">
<div class="modal-overlay" #click="displayed = false"></div>
<div class="modal-content">
<slot/>
</div>
</div>
</transition>
</template>
<!-- SomeDeeplyNestedComponent.vue -->
<template>
<teleport to="#app">
<!-- Can still receive props from parent -->
<MyModal :my-prop="foo">
<!-- slot content -->
</MyModal>
</teleport>
</template>
Vue 2
Move the elements own self to the element of applications root may be achieved in two ways, Using a portal as a preferred solution or using an append.
Using a Portal (Preferred Method)
PortalVue is a set of two components that allow you to render a
component's template (or a part of it) anywhere in the document - even
outside the part controlled by your Vue App!
https://portal-vue.linusb.org/
Using an Append (Not best practice)
If adding a portal library is too heavy, using an append is allowed but lightly discouraged officially in the VUE docs.
Typically this particular mount position will satisfy a z-index overlay for your own modal or dialog popup that you require to render over the top of the entire app. You can always substitute this.$root.$el in this example for a different element target using standard getElementBy or querySelector functions.
Here the element is being moved not destroyed and re-added, all reactive functionality will remain in tact.
<script>
export default {
name: 'modal',
...
mounted: function() {
this.$root.$el.append(this.$el);
},
destroyed: function() {
this.$el.parentNode.removeChild(this.$el);
}
}
</script>
On mounted the element is moved inside of where the top level VUE app instance is mounted.
On destroyed removes the placeholder DOM comment for the migrated component from the new parent to prevent orphaned duplication each time the component remounts it's self.
VUE officially states not to destroy an element outside of VUE so this is not to be confused with that statement, here the component has already been destroyed.
This DOM comment duplication will typically happen when for example switching views with vue-router as this mechanism mounts and dismounts all components in a router view each time vue-router view state changes.
This behaviour is a bug cause by vue-router, the object is destroyed properly by VUE render manager but an index reference remains by mistake, using a portal package resolves this issue.
Here is the result: