I have a big component that has 3 important functions in it--Search, Filter, and Display. I want to put each function into its own component. Filter uses a function from Search, and Display uses a function from Filter. So to pass the functions via props to each component would force me to make Display a child component and Search the parent: Search --> Filter --> Display.
Search is merely a container with logic, and it doesn't make much sense to have it be the parent component. It would be ideal if I could have the structure be Display --> Filter --> Search. Although that would require me to pass the Search function up to the parent component Filter, and Filter pass its function up to the parent component Display.
My question is, what can I do to get these components in the right order, so Display becomes the parent component, yet each component still gets the functions they need from the other components?
Related
I have the following situation:
I have a parent React component and a child.
The parent has a table and the child has some controls of its own.
What I want to accomplish is being able to click on a cell in the parent table and have the cell value get transferred over to the child so that the user can edit it there.
This is what I implemented:
I record the cell value in state in the parent on click.
When this I record this value, a re-render happens and the string gets sent to the child via props.
The issue I'm running into is that if something forces a re-render on the parent, that value will get sent to the child again, even though the child may have changed it.
To solve this, what I thought of originally was to send the prop down to the child and then have the child reach back up via a callback to the parent to clear the value in the parent's state. I fall into a loop doing this so naturally it doesn't work.
What is the correct way to send data down into a child component and then have it get cleared post-render?
Each React component update will dispatch a re render action. And when a child component receive new props that component will to re render too.
Note that a child item should be re render only if the props values are news o the inner component state have changed.
For your situation I say: you can pass a object to your child component using props, and execute an function in the parent inside of the child. You only need pass the function in the parent to the child component as a prop, after, execute it inside the child component when you need it.
State that is passed down to children via props should be modified by the parent. I would look into 'react lifting state'
Class Component:
But essentially, your child's handlers (ex. handleClick) should be declared in your parent component and passed down to your child component as an onHandler (ex. onClick=this.onHandleClick) and in the child can be referenced as this.props.onClick
Functional Component:
Basically the same thing but you shouldn't use the this. reference.
I have a parent component that loads dinamycally childs components via *ngFor. My parent component loads data for rendering child components. There is extra data needed after on user request.
The html of parent component:
<panel *ngFor="let item of collection" (selected)="onTogglePanel($event, item)">
<div panel-body>
<item-detail
*ngIf="item.detail; else templateLoading"
[detail]="item.detail"
(eventItemLoad)="getExtraData($event, item.detail)"
></item-detail>
</div>
</panel>
Each child component, emits an event to the parent component, that will make an http request for getting the data.
The question is, how can I pass the data to the sepecific child component?
I have been reading about invoking child method from parent, but I don´t know really how to invoke only for specified child.
NOTE: Perhaps my approach of parent getting data and passing to children is not correct and each child should get the data. Any advice for the approach is welcome. Thanks for any help.
The child should get the data on its own.
It looks like you just need item.detail to get the additional data. So if you don't need anything from the parent, just let the child make the http request.
This is about separation of concerns : in Angular you achieve this by creating components, each one serving its specific purpose - and not "messing" with another one if it is not needed.
I have one component(container) and 3 nested child components live inside that. Let us take it as First component.
Also I have another component, Let us take is as Second component which is not related to the first component.
I need to move all view elements (nested components) from first component into the second component dynamically.
I have two different components in my React application.One component to display pop up, and other for text search field.
There is no relation(parent-child)between them.
My question is when user clicks pop up message(component), be focused text field in another component.
How can I handle this situation without using document.getElementById?
only using a react a specific way like reactDOM with ref.
Is it possible to handle like that?
Thanks
Find the common parent component, and write a function which updates a state with ref of the element to be focused. Pass down that function as props to the second component.
And use <input ref={r => this.props.func(r)
Now on click of first component you can access this parent state.
I have a child component that renders several list elements from an array. This child component's list items when clicked turns to input boxes, and can be changed. But I need to also put focus on the input box when it's rendered.
Here is a quick view of what my app is so far.
I'm making list items from an array in the state and it's then mapping around while populating the array items in the parent components render function (like any other tutorial shows).
render: function() {
var listItems = this.state.ingredients.map(function(item) {
return <ListItem key={item.id} id={item.id} refer={item.ref} handleChange={this.toggleEnv} env={item.env} ingredient={item.text} />;
}.bind(this));
id for callback from the child component to search the array using id.
env for toggling states from list item to input box and back to list item.
toggleEvn is the function i use for every manipulation of the child component with callback a child component make.
Now that refer property where I pass the item.ref to the child component so it can attach it to the input and then use
componentDidMount: function() {
ReactDom.findDOMNode(ref-name-passed-from-child-component-callback).focus();
}
Where in the child element i pass clicked list items ref (which is equal to input box's ref) to the callback so it can be captured by the parent but it passes null so i can't add the focus from ReactDom.findDOMNode().
I checked in react documentation and they say something like
Never access refs inside of any component's render method – or while any component's render method is even running anywhere in the call stack
I'm a very newbie in react and i think this is referring to my current situation.
But they also have another way of using refs by passing a callback in ref which will be used when some button is clicked as seen here https://facebook.github.io/react/docs/more-about-refs.html
I followed the example by
Adding a ref callback like this ref={(ref) => this.myTextInput = ref}
in my input tag.
Instead of the button, i triggered the function when the list item is clicked. This doesn't work since the this.myTextInput isn't created yet. (Since this function is triggered when list item is clicked and it's before the input is rendered.
At this point i was stuck completely because i can't pass this ref to check it in componentDidMount.
I'm convinced that I'm missing on some understanding here please with refs, child components and callback. Please help.