I have a form built with Vue with a hierarchy of components using v-model to bind the data to the model.
Now I want to fill the form programmatically. If I just update the model (data) of the top component, it has no effect on the child components since this only changes their props.
Here's an example:
https://jsfiddle.net/eywraw8t/411545/
When you click the 'Set to 2018-Oct' button, the model on the myApp is updated, but not the model of the <mydate> component.
Is there a way to achieve filling the form without adding watchers to value props (which the official guide doesn't suggest) on all components in the hierarchy?
Related
In my vue cli project I have a route Settings with 3 child components SettingsA, SettingsB and SettingsC. Each child component has ca. 15 input fields, so it would be too many input fields for one single component.
The goal is to get data from a REST backend with an an axios call when the Route Settings is loaded, and populate some of the input fields with the data;
the user can then navigate between the child components and fill/change the input fields, without triggering the axios call which would reload and overwrite the users input field changes.
Since there are 3 child components I use vuex as store. That way the users inputs should not change when he navigates between the child components.
My question is: Where and with what hook should I make the axios call? With beforeMounted on the Settings Component?
Maybe there is also a better, already tried design than mine?
Thanks for your help!
Solution using custom events
You actually not necessarily need vuex. Basic idea is to have parent component Settings, which includes SettingsA, SettingsB and SettingsC, which are displayed conditionally using v-if. The Settings component is holding your state. Changes in the child components form fields trigger events with this.$emit(). The parent component listens to the events and updates its state. The state of the form is passed down via props.
Solution using Vuex actions
If you go the Vuex route, you will trigger actions instead of using this.$emit() and update the global store. You should import the actions using mapActions. In your components you then have access to the global store using this.$store.
I have parent component that contains form component and detail component for created_at and updated_at in editing Product page.
Form is to edit the existing data and detail component will be next to the form.
I didn't have the detail component before so I fetch data from form component and use it in the component however I need some of the data in detail component which is the child of the parent of the form component.
So I moved the fetch axios to parent component and pass the data to both children now.
Is it better to do this way or is it better to send axios request both in form component and detail component?
The form is also used in adding new product.
My opinion is that you should fire requests from most top level possible. This way your children components (building blocks) can work independently from your current context. It's called presentational component and it's role is to output some markup. The container component feeds the data to the presentational component making the data flow go from top to the bottom nicely.
So in short, you did it right! However you should be careful, when your data changes in the edit form, then you probably want to fire the request on parent again, so that the data is updated for the whole app. This kind of flow is highly facilitated by Vuex. It serves as single source of truth (data) that your whole application can rely on.
I have a component that represents an option in a form, with data representing the currently selected option. There is a parent component which represents the full form, with a submit button and a reset button. I keep track of what options are currently selected in the form by emitting events from the child to the parent (this is important because the form updates dynamically)
.
I'm trying to design the reset button, which clears all fields in the form (sets the currently selected option to an empty string). I would need to modify the data of the child component. Should I do this using a Vue instance as a bus? That seems overkill. Is there a better way to design these components?
I think you want to use sync on the properties your passing into the child component. I use it to load my child component like:
<textbox :content.sync="new_comment" placeholder="Add a comment..."></textbox>
If you already emitting from your child component then changes to new_comment will automatically be passed through.
You can find a lot of ways to do this here.
For me, after a lot of playing around with props, i found that the best and safest way is to use this.$refs.
Even if you have more than one child component with the same ref name, you can go through each child with a forEach.
You can create a custom event to listen to the reset button on each form field. Check out the documentation for this here
Just put a method in the child, perhaps Clear, and call it from the parent. You use $refs in the parent to get to the children.
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.
I have a modal component with textarea which I use to edit data that's in my main instance. So the idea is when I open the modal component, the textarea should be showing current data value from the main instance, this can be done by passing data as prop to the modal component. But since it's prop, vue doesn't allow me to edit it in textarea. And if I use v-model for the textarea, how do I get the original data value the moment my modal popup?
Back in 1.x, I just need to add "two-way: true", but this approach depreciated in 2.0.
pass myProp object as a prop and on the text area you pass v-model="myProp.cellModel"