I am trying to create fully reusable component using Vue.js 2 and single file components, and right now my approach seems to be impossible to realize.
The goal is to create component for creating forms for a complex, nested JSON structure. This structure is supposed to be edited and then sent to the server. The component itself displays a header and submit button but the fields along with their placing is entirely the responsibility of the user of my component. (front-end engineer)
The MyForm component (implementation is not relevant here) is passed the JSON data and url to post them to.
The form is supposed to be reusable by many other users and the contents of the form itself is supposed to be not relevant. It may have a mix of html/inputs/custom components as children.
Let's imagine a simple scenario without data nesting with the following data:
var mymodel={ name : "My name", surname : "My surname" }
And a form i would like to create using my component:
<MyForm :model="mymodel" :url="http://localhost/post">
<div>
<MyTextInput v-model="model.name" label="Name"/>
<MyPanel>
<MyTextInput v-model="model.surname" label="Surname"/>
</MyPanel>
</div>
</MyForm>
Therefore:
MyForm gets passed a model to submit, stores it in data
MyTextInput is a custom component for displaying input with label
Second MyTextInput is the same component but created in another component contained called 'MyPanel' since this field needs to be placed differently.
As we can see there are many problems with passing variables and composition itself:
Composition:
If i put a <slot></slot> in the tempplate of MyForm for displaying the fields it would be compiled in parent scope, therefore all children (including MyTextField) would not have access to the "model"
If i try to use <MyForm inline-template> i cannot automatically display the form header and footer since all content is being replaced. Additionally when using single file components the compiler will look for all components inside the inline-template which means that i would have to import MyTextInput and MyPanel into MyForm which is not practical. I do not know in advance all components that will never end up in my form!
Passing variables:
If i use the variables directly from "model" (in first TextInput) i receive warning that i am modifying a variable from parent and it will be overwritten on next render (but in this case it will not be overwritten since i am INTENTIONALLY modifying the parent)
I cannot pass the model into second MyTextInput without passing it to MyPanel first. Actually i would have to pass it into EVERY custom component in between. And i do not know in advance how many custom components will there be. Which means that i would have to modify the code of every component that would ever be put into MyForm and require users to pass the data for each custom component they include.
If i would try to properly inform the parent about changes i would need to add v-on: event to every textinput and every custom component in between in order for the event to reach MyForm.
As i have said the component was supposed to be simple and easilly reusable. Requiring users of this component to modify code of every child they put into it and requiring them to add v-on: to every component inside does not seem practical.
Is my idea solvable using Vue.js 2.0 ? I have designed the same component before for AngularJS (1.5) and it was working fine and did not require to add modifications to each child of the form.
I've been using a ui framework based on vue 2.0 and you may get some ideas from its implementation. Based on its implementaion and my little experience with it, I think it's the person who uses your framework's responsibility to assemble the form-model. Also, for a form, we can always easily get all the data to be sent by using fields' value props without v-model's help.
The framework's doc on form element may also be helpful but it's currently only available in Chinese except for the code samples.
I suggest you to use Form Input Components using Custom Events to pass variables in your form.
Mutating a prop locally is now considered an anti-pattern, e.g.
declaring a prop a and then set this.a = someOtherValue in the
component. Due to the new rendering mechanism, whenever the parent
component re-renders, the child component's local changes will be
overwritten. In general, in 2.0 you should treat props as immutable.
Most use cases of mutating a prop can be replaced by either a data
property or a computed property.
Related
I have a VueX state that contains a list of items. E.g.:
{
operations: Operation[]
}
We need to display each Operation as an item in a list. So we have an OperationList component and an OperationItem component.
When it comes to rendering the list (v-for), would it be recommended to pass the entire item as a prop or just the id and have the OperationItem read the data from VueX?
Basically:
<operation-item v-for="operationId in operationIds" :id="operationId" :key="operationId"/>
vs
<operation-item v-for="operation in operations" :operation="operation" :key="operation.id"/>
I think it might be a preference choice but in my projects I usually pass all the prop of the components that way :
<operation-item
v-for="operation in operations"
:key="operation.id"
:prop1="operation.prop1"
:prop2="operation.prop2"
:prop3="operation.prop3"
/>
I'm not sure if that's a good practice or not but in this case, it's more flexible, you don't need to give a structured object for it to render, you just have to give it all it's properties.
A bit like for a class constructor, I would pass all the necessary parameters separately instead of passing them in an $option array or Settings class.
For some components, it also doesn't make sense for them to be aware of the store, they should juste be "stupid" rendered components.
I hope it's clear enough that you get my point !
I'd say pass the entire item. That way your component doesn't need to know where the data came from and you would be able to reuse the component in situations where the data didn't come from Vuex.
mount on a component does not fire for v-bind changes to the component in the root.
I have a dynamic component where I often change the value of the data referenced in v-bind:is and v-bind attributes, switching the current component and its data. This works great to show different "screens" of my application.
I have some logic that happens on mount for many of the components. However, this only gets called when the v-bind:is value is changed, but no when only the v-bind attribute is. That sort of makes sense to me, though I do need to capture either.
I'm new to Vue and there is a lot of documentation. I'm so far unable to determine if there's a built-in functionality for a callback to v-bind:is and v-bind. Can anyone help me out here?
I construct deep nested tree of parent and children Vue custom components using my top level component dynamically and then I am updating the data from which all tree is constructed. Which has an effect of rendering the entire tree (its a form with various custom components). I refresh/rebuild the whole form after fetching the data (which is what vue do for reactive data) that itself tell me how to regenerate the view (its like a JSON Schema from which I render the entire view).
This is related to my other issue here.
I am observing a very weird behavior in my Vue Application. When I destroy all my children components and rebuild the data to force rendering the form, it appears that even after I have called $destroy on every child component...Vue is not entirely removing them from cache?
Does vue remove the component from cache if a $destroy is called ?
Because I do not see multiple components of the same type in the Vue component list in the Chrome Vue DevTool extension panel. But I see that the same custom event is handled twice by the same component. Same function that handle the events is getting called twice even though there is only one component visible in Vue DevTools of this type.
This only happens after I render the form. When the page is loaded for the first time every thing works. Then after I reset the form by destroying the child component and resetting the data to re-render the form, magically this child component start handling the event twice.. and in 3rd render it handle the events thrice. But I see only one component in google chrome VueJS DevTool extension panel. So my guess is that vue is still keeping the previously destroyed component in cache. I am trying to figure out how should I destroy those components in the cache.
If anyone has observed something similar and found a solution please let me know.
At the moment I am going to dig little bit more on my component keys (this particular component does not have explicit key set by me).
First and foremost, the vue documentation states:
vm.$destroy
In normal use cases you shouldn’t have to call this method yourself.
Prefer controlling the lifecycle of child components in a data-driven
fashion using v-if and v-for.
So instead of destroying and rebuilding the components manually yourself, you should really letting vue handle that via v-if and v-for. If the components aren't updating to your changes, you might be dealing with a reactivity issue.
As you mentioned that this is a deeply nested structure, the reactivity is key to keeping the components up to data with the data.
Vue does not allow dynamically adding new root-level reactive properties to an already created instance. However, it’s possible to add reactive properties to a nested object using the Vue.set(object, key, value) method:
Vue.set(vm.someObject, 'b', 2)
Inside of a component:
this.$set(this.someObject, 'b', 2)
Also, keep in mind that Vue should be doing the heavy lifting in regards to component management, while you should define the parameters by which a component is rendered.
I am currently developing a web application that is used to display elements for events on a map provided by HERE Maps. I am using Vue.
I have some components, but the relevant component is the component HereMaps.vue which initializes the map using the HERE Maps Api.
The HERE Maps Api provides the possibility to place so called InfoBubbles on the map showing additional information. These InfoBubbles can be provided some HTML-code in order to customize their appearance.
Please refer to the documentation for additional information
Following the documentation the code looks something like this:
let bubble = new H.ui.InfoBubble(marker.getPosition(), {
content: "<div class='someClass'>Some Content</div>"
});
this.ui.addBubble(bubble)
This is happening after mount in the "mounted" method from Vue in the "HereMaps" component.
The Bubbles are added in a "closed" (hidden) form and dynamically "opened" to reveal their content when the corresponding marker icon on the map is clicked. Therefore the HTML-code is present on the DOM after the component is mounted and is not removed at a later stage.
Now instead of supplying custom code within each bubble added to the UI i want to just add a component like this:
let bubble = new H.ui.InfoBubble(marker.getPosition(), {
content: "<myDynamicComponent></myDynamicComponent>"
});
this.ui.addBubble(bubble)
It does not matter to me wether the component is initialized using props or if it is conditionally rendered depending on the state of a global variable. I just want to be able to use the "myDynamicComponent" in order to customize the appearance in a different file. Otherwise the design process gets very messy.
As far as i know this is not possible or at least i was not able to get it work. This is probably due to the fact that the "myDynamicComponent" is not used within the "template" of the "HereMaps" component und thus Vue does not know that it needs to render something here after the directive is added to the DOM in the "mounted" method.
This is what the InfoBubble looks using normal HTML as an argument:
This is what the InfoBubble looks using the component as an argument:
It appears to just be empty. No content of the "myDynamicComponent" is shown.
Does anyone have any idea how i could solve this problem.
Thank You.
Answer is a bit complicated and I bet you wouldn't like it:)
content param can accept String or Node value. So you can make new Vue with rendered your component and pass root element as content param.
BTW, Vue does not work as you think, <myDynamicComponent></myDynamicComponent> bindings, etc exists in HTML only in compile time. After that all custom elements(components) are compiled to render functions. So you can't use your components in that way.
Give us fiddle with your problem, so we can provide working example:)
I've got an existing SPA that was developed using nested RactiveJS components. Which is great, and offers a ton of flexibility throughout the entire app. Currently I attempting to add in client side routing support using page. My navigation switches out high-level components using simple {{#visible}}{{/visible}} template markup on each component. This is a little troublesome in its current state as it always kicks off a re-render whenever the high-level component becomes visible again.
Is there a way to render a component, for example, called widget, without using the
<widget></widget>
method? I've already "registered" the component with the parent, but obviously when constructing it by means of
new App.components.widget
I am able to control how/when it's rendered/inserted/detached, but lose the recognition in the application's component hierarchy.
There is insert exactly for that. You don't even need to "register" it to the component you plan to put it to. You can use the different find* methods or nodes to easily retrieve a reference of your planned container element.
var instance = new YourDetachedWidget({ ... });
instance.insert('#your-container'); // This could be a node, selector or jQuery object