vue.js: How to specify which child component to use? - javascript

In my app there are generic and brand specific components. Let's say I have 2 brand specific components Product_brand_A.vue and Product_brand_B.vue, which I would like to display in a list. The parent component ProductList.vue is generic (used for both brands).
What are my options in ProductList.vue to specify which child component to use?
// ProductList.vue (generic)
import Product from 'Product.vue' // importing won't do
var ProductList = {
components: {
Product
},
...
}
I don't want to import both child components and decide at run time, it should be a build time solution.

I think that it's better to use slots api here. Here's example of usage of the list component:
<ProductList :items="someProductsBrandA">
<template v-slot:item="props">
<Product_brand_A product="props.product">
</Product_brand_B>
</template>
</ProductList>
This way you can add as much different product components as you want in the future. You can check the slot API here: https://v2.vuejs.org/v2/guide/components-slots.html

If you don't want to import both subcomponents then you would probably need to use dynamic importing:
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/import#Dynamic_Imports
Then you could dynamically import the subcomponent you need based on some prop that you pass to the parent (ProductList.vue).

Related

Vue - make helper for root component and all child component

Please is there a way to create a helper function on a root component in vue and also make the function accessible in all child components?
You can create helper functions and use it as a plugin. In case of you are using nuxt.js, you can create helpers.js in plugins and register it in nuxt.config.js file.
import Vue from 'vue'
import helpers from './helpers'
const plugin = {
install () {
Vue.prototype.$helpers = helpers
}
}
Vue.use(plugin)
In helpers.js, you can define all helper functions.
export default {
cloneObj(val) {
return JSON.parse(JSON.stringify(val));
}
};
Then you can use it in any child components like this:
this.$helpers.cloneObj()
You need to store it in a separate file because it's frustrating to pass it as a prop from one component to another and that's the main idea of why state management like Vuex is a better solution because it provides a centralized state manage which you can access from any component

How do I extend React components already in use?

This applies to just about any scenario along these lines:
I have a React app that uses React Router <Link>s, and they are scattered throughout my app. I want to extend or prototype the <Link> component so that there is a new attribute when they are rendered. (I just want to add an attribute to all Link tags.)
How can I update the Link component that is being used throughout the app, to have a new attribute [without creating a new component, like <CustomAttributeLink>]?
Thanks
The best way to do this is by cloning the element, you should use React.cloneElement. To make the component usable everywhere, just create a new component using it, and export it.
import React from "react";
import {Link} from "react-router";
const CustomLinkAttribute = React.cloneElement(Link, {
newProp: "New prop val here"
});
export default CustomLinkAttribute;
You can clone the element and add the extra props using React.cloneElement e.g:
var clonedElementWithExtraProps = React.cloneElement(
MainElement,
{ newProp: "This is a new prop" }
);
Return clonedElementWithExtraProps;

ReactJS - Accessing data on Different Pages

I am trying to access data gathered from a user on one page and use it on another page. I have tried following these articles:
https://travishorn.com/passing-data-between-classes-components-in-react-4f8fea489f80
https://medium.com/#ruthmpardee/passing-data-between-react-components-103ad82ebd17
https://codeburst.io/react-js-pass-data-from-components-8965d7892ca2
I have not been able to get it to work. this.props.{variableName}keeps returning as undefined. My code is as follows.
The following is the Home Page:
import React, { Component } from 'react';
import {Button} from 'reactstrap';
import { browserHistory } from 'react-router';
class HomeScreen extends Component {
constructor(props) {
super(props);
this.state = {
working: "",
};
}
WorkReqNav(){
this.setState=({working: "WORKING"});
browserHistory.push("/WorkReq");
}
render() {
return (
<div>
<Button size="lg" onClick={this.WorkReqNav.bind(this)} type='button'>HIT IT!</Button>
</div>
);
}
}
export default HomeScreen;
The following is the workReq screen:
import React, { Component } from 'react';
import {Button} from 'reactstrap';
class WorkReq extends Component {
constructor(props) {
super(props);
}
workCheck(){
var working = this.props.working;
alert(working);
}
render() {
return (
<div>
<Button size="lg" onClick={this.workCheck.bind(this)} type='button'>HIT IT!</Button>
</div>
);
}
}
export default WorkReq;
If you need anything more, please let me know. i am really new to React and this is my first time attempting anything like this.
welcome to the React world. I bet you'll love it when you gradually get familiar with cool stuff that you can do with React. Just be patient and keep practicing.
So the first suggestion I would make is that, like any other javascript environment, React also evolves very quickly. So although basic principles are the same, when you follow a new article on one hand, on the other hand you can check if the libraries or methodologies that are demonstrated are up to date.
Fasten your belts and let's do a quick review based on your question and libraries that I see you used in your example.
In terms of router, I see that you directly export things from react-router
When we check the npm page (https://www.npmjs.com/package/react-router) of react-router they make the following suggestion
If you are writing an application that will run in the browser, you
should instead install react-router-dom
Which is the following package https://www.npmjs.com/package/react-router-dom
You can get more details and find more tutorials in order to improve your skills by checking their official page https://reacttraining.com/react-router/web/guides/philosophy
Let's take a look at the code snippet sasha romanov provided that's based on react-router-dom syntax
with react-router-dom when you define a route with following syntax
<Route path="/" component={HomePage} exact />
react-router-dom automatically passes match, location, and history props to HomePage component. So when you console.log() these props, you should be able to display somethings on your console. And once you have access to history props, instead of browserHistory, you can use this.props.history.push("/some-route") for redirections.
Let's take a look at the part related to withRouter. In the example above, we could use history because HomePage component was passed directly to the Router component that we extract from react-router-dom. However, in real life, there might be cases in which you want to use history props in a component that's not passed to the Router but let's say just a reusable button component. For these cases, react-router-dom provides a Higher Order Component called withRouter
A Higher Order Component is (from React's official documentation)
https://reactjs.org/docs/higher-order-components.html
Concretely, a higher-order component is a function that takes a
component and returns a new component.
So basically, whenever you wrap any component with withRouter such as export default withRouter(MyWrappedReusableComponent), in your reusable component, you will have access to the props history, location, pathname
That said, my first impression regarding to your problem does not seem to be related to router logic but rather exchanging data between components.
In your original question, you mentioned that
I am trying to access data gathered from a user on one page and use it on another page
There are a couple of cases/ways to approach this issue
1) If these two components are completely irrelevant, you can use state management system such as Redux, mobx or you can use React's context API https://reactjs.org/docs/context.html. HOWEVER, since you are new to React, I would suggest not tackle with these right know till you are comfortable with the basic flow. Because at some point trying to implement a flow with a lot of libraries etc. is quite overwhelming. Believe me, I tried when I was also new to React and I was really close to break my computer after opening my 100th browser tab to look for another method from another library
2) You can implement a simple parent-child relationship to pass data between components. Let me explain what I mean by using references from your code snippet.
I believe you want to update working which is a state in your HomeScreen and you want to pass and use this updated value in your WorkReq component.
If we ignore all the routing logic and decide to go without routes, what you need to do is the following
import React, { Component } from 'react';
import {Button} from 'reactstrap';
import { browserHistory } from 'react-router';
import WorkReqComponent from 'path/to/WorkReqDirectory';
class HomeScreen extends Component {
constructor(props) {
super(props);
this.state = {
working: "WORKING",
};
}
render() {
return (
<div>
<WorkReqComponent working={this.state.working} />
</div>
);
}
}
By this way, when you log this.props.working; in your WorkReqComponent you should be able to display the data that you passed. You can refer to this as passing data from parent to child.
I checked the articles you listed. They also seem to explain data transfer between parent to child, child to parent or between siblings.
In your case, what you really need to implement can be categorized as between siblings
I prepared a sample for you with react-router-dom to demonstrate one possible structure which might yield your expected outcome.
https://codesandbox.io/s/ojp2y0xxo6
In this example, the state is defined inside of the parent component called App. Also state update logic is also defined inside of the parent component. HomeScreen and WorkReq components are the children of App thus they are siblings. So, in order to transfer data between siblings, one of them was given the task of updating parent's state via passing state update logic to this component. The other one has the task of displaying parent's state's value.
At this point, since you are new and in order not to overwhelm yourself, you can experiment with parent-child-sibling data transfer topic. Once you are getting comfortable with the implementation and the logic, you can gradually start taking a look at React's context api and Redux/mobx.
Let me know if you have any questions regarding to the sample I provided
You can use react-router-dom lib and from seeing your code i think in parent component (app.js) you defined route for each child component you'd like to access
like this example here:
import { BrowserRouter, Route, Switch } from 'react-router-dom';
<BrowserRouter>
<div>
<Switch>
<Route path="/" component={HomePage} exact />
<Route path="/homescreen" component={HomeScreen} />
<Route path="/workreq" render={(props) => <WorkReq {...props} />} /> // here you can pass the props by calling render
<Route component={NoMatch} />
</Switch>
</div>
</BrowserRouter>
and then if you want to change route you can just call this.props.history.push('/workreq')
and if you didn't include route for the component in <BrowserRouter />
in the component that it's not included you can import withRouter and export like this withRouter(HomeScreen) and now you can access router props
if this isn't the answer you are looking please inform me to update my answer, i hope this can help

VueJS Unknown custom element: did you register the component correctly

I wanted to use this third party toast component in my VueJS app but it is giving error,
Unknown custom element: <toast-container> - did you register the component correctly? For recursive components, make sure to provide the "name" option.
main.ts
import VueOnToast from 'vue-on-toast';
..
Vue.use(BootstrapVue, Vuex, VueOnToast);
App.vue
<toast-container></toast-container>
See the signature of Vue.use:
Vue.use( plugin )
Vue.use only expects a single argument. If you pass more than that, they are ignored.
You have to use it like this:
Vue.use(BootstrapVue);
Vue.use(Vuex);
Vue.use(VueOnToast);

How does import work with react?

My broader question is does an import of a module get shared between two components and why?
First what do I know about import. You can import in two different ways.
1.
At the top of your file which loads the imported module into a variable which you then can use.
import Highcharts from './highcharts'
// create a chart
Highcharts.Chart()
2.
Or dynamically anywhere in your code which returns a promise:
import('./highcharts').then((response) => {
// create chart
response.Chart();
});
But there is this weird behavior I don't understand when using import with react. If I have the following component:
import React, {Component} from 'react';
import Highcharts from 'highcharts/js/highcharts';
export default class Chart extends Component {
state = {
chartOptions: {
// my chart options and data
}
}
componentDidMount() {
if(this.props.extendFunc) {
import('highcharts/js/modules/funnel.src.js').then((funnelModule) => {
funnelModule(Highcharts)
})
}
Highchart.Chart('myChart', this.state.chartOptions)
}
render() {
<div id="myChart" />
}
}
I use the component from above twice. Now there is this behavior that both components use the same import e.g. the import of Highcharts does not happen twice. I noticed this because with Highcharts there is the option of extending the functionality.
If I for example extend the functionality for Chart 1 by passing a prop to extend it, the functionality of Highcharts is also extended in Chart 2, although I didn't pass a prop to extend the functionality.
import React, {Component} from 'react';
import Chart from './Chart';
export default class Dashboard extends Component {
render() {
return (
<div>
<Chart extendFunc={true}> Chart 1 </Chart>
<Chart> Chart 2 </Chart>
</div>
)
}
}
What causes this behavior? Is this react or is this just the way import works? Are imports global for multiple instances of the same component? Or are imports of a node module the same for the whole application?
What causes this behavior? Is this react or is this just the way import works? Are imports global for multiple instances of the same component? Or are imports of a node module the same for the whole application?
This is the way imports work. When you import something for the first time, the file is run and the exported values from it are returned back to the one importing it. When something is imported again, those same exports are reused and returned. Node JS modules work the same way.
Sometimes this behavior is helpful, firstly for performance to avoid unnecessarily re-running the same file over again, and also if the module wants to store some internal state. For example, counting the number of times a function is called from anywhere in the application.
In cases like this, where you need a single instance of something for each script, modules will usually give you a way to actually make an instance of that thing. For example, I might have a logging module, which exports a Logger class, then I can make new instances of that class for each component, and configure each logger separately.
For your case, look in the docs to see if there's a way to make per-component instances of Highcharts and extend that individual instance with the functionality you need.
When you extend <Chart /> with a prop extendFunc it will be extended in your Chart Component and not in your "new" Component.
That means, if you call the component, it will always have the props you gave it, but you will not have to use them (if there are not set as required).

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