v-if breaks nuxt ssr - vue.js

If I use fetched data (fetchPolicy: 'cache-and-network') from apollo in v-if, it will throw
vue.runtime.esm.js:619 [Vue warn]: The client-side rendered virtual DOM tree is not matching server-rendered content. This is likely caused by incorrect HTML markup, for example nesting block-level elements inside <p>, or missing <tbody>. Bailing hydration and performing full client-side render.
<template>
<div
<div v-if="test">
{{ test }}
</div>
</div>
</template>
but if I use it just as variable to render it works fine.
<template>
<div>
{{ test }}
</div>
</template>
The data in real usage is object, that I need to conditionaly render and pass to another components with v-if.
I have tried geting the data trough get, doing watch over the data and seting them manually, but eventually everything broke.
regarding comment:
if I console the test data it will go -> true on server -> false on client and then true on the client again, if I remove the test from v-if it goes: true on server and true on client
this has nothing to do with structure, in real project it has bunch of components and it works just fine if the data isnt used in condition

For anyone facing the same problem, I have fixed it by setting cache-and-network after the mount and all works just fine.
mounted() {
this.$apollo.queries.getCampaign.setOptions({
fetchPolicy: 'cache-and-network',
})
}

You are trying to make the root element of a component conditionnally disappear, which creates an inconsistency in the virtual DOM.
Can you try:
<template>
<div>
<template v-if="test">
{{ test }}
</template>
</div>
</template>

from my experience, nuxt will failed in SSR if you are using v-if unless you wrap in <no-ssr> or <client-only>

SSR is sometimes difficult to debug and such problems occure quite often.
https://ssr.vuejs.org/#why-ssr
some external libraries may need special treatment to be able to run
in a server-rendered app.
This may be the point. Some vue-components cannot be run via SSR out of the box. This is why I asked about the content from the server.
So the easiest fix could be to wrap your component with the <no-ssr> tag. You can do this for each component separatly to find out which one causes the problem.
Once you have isolated the component you can keep the <no-ssr> tag on it and migrate it's functions to the mounted area of your client component.

If it is a small component you can also use v-show instead.

Related

Vue-Masonry-Wall package: How to use with NuxtJS2 and SSR?

I am trying to use vue-masonry-wall in my NuxtJS (v2.15.7) app to give it a masonry layout. According to the docs, the vue-masonry-wall package is "SSR friendly". It states to simply add :ssr="{columns: 2}" to masonry so that during SSR, it will be loaded in 2 columns.
I tried this in my code (codesandbox here). But, during SSR, nothing is loaded.
Anyone got any idea on what is happening and why I can't see any of the items? It works fine in client-mode.
Code example:
<vue-masonry-wall :items="items" :options="{width: 300, padding: 12}" :ssr="{columns: 2}" #append="append">
<template v-slot:default="{item}">
<div class="item">
<h5>{{item.title}}</h5>
<p>{{item.content}}</p>
</div>
</template>
</vue-masonry-wall>
One option is to run it just on the client side, so:
1- if loaded as plugin, globally: name the plugin file ending with ".client", for instance: 'vue-masonry-wall.client.js'
2- if used as module, you can wrap it with the tag.

Why are Vue dynamic components destroyed inside loop every re-render?

I run into an issue with Vuejs 2.x version (latest). While rendering a list of item inside a loop, if I make changes to the items then the normal components are not destroyed but the dynamic components will always be destroyed:
I have put a short sample code here:
https://gist.github.com/yellow1912/fc1c053e07c1ca136148484cf7f79d1a
I have also put a codepen here:
https://codepen.io/raineng/pen/zYGOXYY?editors=1111
<nl-test inline-template>
<div>
<div v-on:click="increase"> increase here please </div><br><br>
<div v-on:click="decrease"> decrease here please </div>
<ul>
<li v-for="(value, key) in getItems()" :key="key">
printing
<component :is="getItem()" :key="key"></component>
<nl-test inline-template>
<div>
this is a test here
</div>
</nl-test>
</li>
</ul>
</div>
</nl-test>
To see what I mean, open the console tab on codepen, click the add item and you will see that the dynamic component items are destroyed and re-created everytime.
I found out why, I need to use keep-alive:
https://v2.vuejs.org/v2/guide/components-dynamic-async.html
To quote:
When switching between these components though, you’ll sometimes want
to maintain their state or avoid re-rendering for performance reasons
Recreating dynamic components is normally useful behavior, but in this
case, we’d really like those tab component instances to be cached once
they’re created for the first time. To solve this problem, we can wrap
our dynamic component with a element
Wasted 2 days on this issue and then I found the answer just a moment after posting this on StackOverflow. Hope it helps someone.

Modal window in nuxt architecture

Before I was working with Vue2JS and I used to creating modal as just component within App.vue root component for example:
<template>
<div>
<app-navbar></app-navbar>
<router-view></router-view>
<app-footer></app-footer>
<my-modal v-if="someBoolean"></my-modal>
</div>
</template>
Now basing on some custom events or Vuex storage I was able to change someBoolean and trigger when I want modal to be visible.
Since in Nuxt we don't have such thing as root App.vue component I'm wondering how to achieve same as above but with Nuxt.
Of course I could use some package as bootstrap-vue but I don't really want to inject this big package just for that one purpose.
You can write code in layouts/default.vue file and this file works on your defaults, work the code at where you used as a layout of your pages(generally almost everywhere.)
Different approach is use portalvue to render components whereever you want. Nice article here but in Turkish.

Vue 2.0 server-side-render with template inside #app container

Server side rendering page for reference: ssr.html
Now the problem, what if we want to define template inside the <div id="app"></div> in html file itself, not in Vue instance template property? Like this:
<div id="app">You have been here for {{ counter }} seconds.</div>
In this case if we want to pre-render it, we will get next pre-rendered html:
<div id="app" server-rendered="true">You have been here for 0 seconds&period;</div>
And here is the conflict problem. If we will output pre-rendered html, we lose our template and Vue doesn't know where to output counter inside our <div id="app">.
Is it possible somehow to provide template inside <div id="app"></div> container and in the same time pre-render it? Or provide template near the pre-rendered in html(so Vue will know that here is pre-rendered and here is template and i will use it if any changes happens in the model)?
Is it possible somehow to provide template inside container and in the same time pre-render it? Or
Short but complete answer: No. For Vue SSR, you cannot use in-DOM templates. You have to use string-based templates (including Single File Components).

Oddity with templates and root node with vue.js

I think this is possibly a bug I've stumbled across, not sure. I'm getting this Vue.js warning for a component:
vue.js:2611 [Vue warn]: Cannot use <template> as component root element because it may contain multiple nodes:
The problem seems to be this:
<template id="tpl-field">
<template v-if="fieldType==='checkbox-inline'">
<label class="checkbox-inline">[SNIP]</label>
</template>
<template v-else>
[SNIP]
</template>
</template>
So I have two template nodes, which seems to be the multiple nodes it's choking on (certainly each of the template nodes contains just a single node). Yet this is an if-else in Vue - if one of the nodes is present, the other logically cannot be.
Demo of the problem here: https://jsfiddle.net/jonmor51/Ldz3k0jp/1/. If I wrap everything in a div, it works. But without, it fails. (Unfortunately, in the context where I want to use this, namely for inline checkboxes within a Bootstrap grid, wrapping in a div breaks things).
Not sure if this will solve your problem with bootstrap... but you could wrap you inner templates with a <transition> tag and set a key to each one.
Please check this working fiddle
https://jsfiddle.net/AldoRomo88/7c7znu3p/
helpful thing - just use div display: contents as a root of the component and browser will ignore that element and consider child elements (which can be many) as children of upper dom element
<div style="display: contents">
<template v-if="...">
<template v-for="..."> ...
</template>
<template v-if="...">
</template>
</div
works even inside tables!
The inner templates direct children, are they single elements? If so, you can just remove the inner templates and move v-if to the label.
Or, just use span rather than div as your quick fix, which won't break inline elements' style.