Develop Reference

How to use <component :is=""> in vue 3 script setup

I am using the experimental script setup to create a learn enviroment. I got a selfmade navigation bar with open a single component.
I am having trouble using the <component :is="" /> method. This method is described in the docs under component basics -> dynamic-components
In the Vue 3 Composition API, it works as expected:
<template>
<NavigationBar
#switchTab="changeTab"
:activeTab="tab"
/>
<component :is="tab" />
</template>
<script>
import { ref } from 'vue'
import NavigationBar from './components/NavigationBar.vue'
import TemplateSyntax from './components/TemplateSyntax.vue'
import DataPropsAndMethods from './components/DataPropsAndMethods.vue'
export default {
components: {
NavigationBar,
TemplateSyntax,
DataPropsAndMethods
},
setup () {
const tab = ref('DataPropsAndMethods')
function changeTab (newTab) {
tab.value = newTab
}
return {
changeTab,
tab
}
}
}
</script>
My approach with the script setup fails:
<template>
<NavigationBar
#switchTab="changeTab"
:activeTab="tab"
/>
<component :is="tab" />
</template>
<script setup>
import NavigationBar from './components/NavigationBar.vue'
import TemplateSyntax from './components/TemplateSyntax.vue'
import DataPropsAndMethods from './components/DataPropsAndMethods.vue'
import { ref } from 'vue'
const tab = ref('DataPropsAndMethods')
function changeTab (newTab) {
tab.value = newTab
}
</script>
do you got any idea how to solve this with the script setup method?

It seems with <script setup>, tab needs to reference the component definition itself instead of the component name.
To reference the component definition, which does not need reactivity, use markRaw() before setting tab.value:
<script setup>
import DataPropsAndMethods from './components/DataPropsAndMethods.vue'
import { ref, markRaw } from 'vue'
const tab = ref(null)
changeTab(DataPropsAndMethods)
// newTab: component definition (not a string)
function changeTab (newTab) {
tab.value = markRaw(newTab)
}
</script>
demo 1
If you need to pass the component name to changeTab(), you could use a lookup:
<script setup>
import DataPropsAndMethods from './components/DataPropsAndMethods.vue'
import { ref, markRaw } from 'vue'
const tab = ref(null)
changeTab('DataPropsAndMethods')
// newTab: component name (string)
function changeTab (newTab) {
const lookup = {
DataPropsAndMethods,
/* ...other component definitions */
}
tab.value = markRaw(lookup[newTab])
}
</script>
demo 2
Tested with Vue 3.0.9 setup with Vue CLI 5.0.0-alpha.8

React: store uploaded array into global variable?

I'm currently working on using React to upload a CSV file and convert the data to an array so I can access phone numbers. I've actually got it almost completely functional, with just one problem: I can't figure out how to store the array properly in a variable (dataDump) on the global level. It stores it inside another array.
Here's a picture of my console so you can see what I mean.
I'm able to access the contents of dataDump if I use dataDump[0] (as seen in the function for handleClick), but that won't work for a global variable. I need to be able to send the array's values to other components/files, so I don't think having to call it like that will work. Chances are I'm over-complicating this in my head and the answer is incredibly simple, but I've spent the past 2-3 weeks learning React, Twilio, Mongodb etc. from scratch so my brain's not cooperating.
I'll appreciate any help! Thanks! Code below. (Note this is a component that's imported to the App page.)
import React from "react";
import CSVReader from "react-csv-reader";
var dataDump = [];
console.log(dataDump);
const papaparseOptions = {
header: true,
dynamicTyping: true,
skipEmptyLines: true,
transformHeader: header => header.toLowerCase().replace(/\W/g, "_"),
complete: function(results) {
dataDump.push(results.data);
console.log(dataDump);
var rows = results.data;
let numbers = rows.map(a => a.phone_number); //make the results ONLY the phone numbers
// console.log(numbers);
document.getElementById("data2").innerHTML=numbers; //display the phone numbers
}
};
class Import extends React.Component {
constructor(props) {
super(props);
this.state = {data:[]};
this.handleClick = this.handleClick.bind(this);
}
handleForce = data => {
// console.log(data.length);
console.log(data);
this.setState({data: data});
};
handleClick = () => {
console.log("success");
console.log(this.state.data);
console.log("Next is Numbies:");
let numbies = dataDump[0].map(a => a.phone_number);
console.log(numbies);
document.getElementById("data").innerHTML=numbies;
}
render() {
return (
<div className="container">
<CSVReader
className="csv-input"
label="Select CSV file to import"
onFileLoaded={this.handleForce}
parserOptions={papaparseOptions}
/>
<div>
</div>
<button onClick={this.handleClick.bind(this)}>
Test
</button>
<div id="data" />
<div id="data2" />
<div id="data3">
</div>
</div>
);
}
}
export default Import;
// export default DataController;

Under the hood React-Redux is using context and hooks these days, so don't bother implementing a Redux stack until you've outgrown the simpler, React API, or at least you've fixed your issue. Folks joke that Redux is like shooting a fly with a bazooka. More info on React-Redux internals here and here's the documentation for React's Context.
Some psuedo-code to get you on the right path:
// context.js
import { createContext } from 'react';
export const Store = createContext();
// app.js
import React from 'react';
import { Store } from './context';
import Import from './import'; // I wouldn't change the casing on or reuse a reserved keyword personally, maybe calling this something like 'CsvImporter' would be an improvement
function App() {
const [dataDump, setDataDump] = React.useState([]);
return (
<Store.Provider value={{ dataDump, setDataDump }}>
<Import dataDump={dataDump} setDataDump={setDataDump} />
</Store.Provider>
);
}
Now your import component has two new props, dataDump and setDataDump. You can call setDataDump just like any other call to setting state. Nice!
So you need the dataDump in a new component? That's easy peasy, lemon squeezy, and all without global variables or tossing module scoping to the side:
// foobar.js
import React from 'react';
import { Store } from './context';
export function Foobar() {
// you probably want to do more than force render an array as a string, but this is just a proof of concept
return (
<Store.Consumer>
{({ dataDump, setDataDump }) => (
<p>
`${dataDump}`
</p>
)}
</Store.Consumer>
);
}
Just make sure that Foobar or other components are rendered as children of the Provider in app.js and now you have a 'global' context for passing around dataDumps.

How to correctly globally register and use Vue Rangedate Picker component?

I am trying to use VueRangedatePicker and I can't seem to figure out how to use this on the template of some other vue component. I am using Webpack.
I have registered the component/plugin on my main.js file like this:
import Vue from 'vue'
import App from './App'
import router from './router'
import { store } from './store/store'
import firebase from './firebase-config'
import vuefire from 'vuefire'
//////////////// HERE
import VueRangedatePicker from 'vue-rangedate-picker' // importing the plugin here
Vue.use(VueRangedatePicker) // using it
Vue.component('VueRangedatePicker', { }) // creating the component globally (if I don't add this line the app complains the component is not registered
////////////////
Vue.config.productionTip = false
let app;
Vue.use(vuefire)
firebase.auth().onAuthStateChanged(function(user){
if (!app) {
/* eslint-disable no-new */
app = new Vue({
el: '#app',
template: '<App/>',
components: { App, VueRangedatePicker },
router,
store,
VueRangedatePicker
})
}
})
Then on my component component_A.vue I am again importing the VueRangedatePicker plugin in the following manner:
<template>
<div>
<vue-rangedate-picker #selected="onDateSelected" i18n="EN" />
</div>
</template>
<script>
import firebase,{ itemRef } from '../firebase-config';
import VueRangedatePicker from 'vue-rangedate-picker'
export default {
firebase() {
return {
items: itemsRef,
}
},
name: 'component_A',
data () {
return {
}
},
created() {
console.log(VueRangedatePicker);
},
methods: {
onDateSelected: function (daterange) {
this.selectedDate = daterange
},
}
</script>
I know the plugin/component is registered because when I log the Vue Rangedate Picker on the console I can see the object
However I am getting the an error message like this
I have read the complete readme.md file on the project's github but I am still puzzled. What is Vue_Daterange_picker? Is it a plugin? Is it a component? Is it a plugin that allows me to build a component? I am quite confused. Can you clarify this for me a little better? How can I make this work?

This is because you have registered the component with an empty name.
In main.js :
Vue.component('DatePicker', VueRangedatePicker)
Then in your component use the component as :
<date-picker></date-picker>

Bundle.js not recognizing one of my files?

Please bear with me because I am a javascript newbie, and just starting to learn react.
I am trying to make a small app but I keep getting an error that one of my files is not found... specifically this:
bundle.js:56 Uncaught Error: Cannot find module "./components/search_bar"
My file structure is that I have my index.js in a folder called src, then my search bar(search_bar.js) in a folder called components. I have triple checked the spelling on them but I continue to get this error.
This is my index.js
import SearchBar from './components/search_bar';
import React from 'react';
import ReactDOM from 'react-dom';
//Create a componant (some /HTML)
const API_KEY = 'AIzaSyC3Z3qTpvAacDLYEIxaueKflFJbWvdIHsw';
const App = () => {
return (
<div>
<SearchBar />
</div>
);
}
// Put that componant on the page (the DOM)
ReactDOM.render(<App />, document.querySelector('.container'));
And this is my search_bar.js
import React, { Component } from 'react';
class SearchBar extends Component {
contructor(props) {
super(props);
// when user updates the search bar this term will get updated.
this.state = { term: ''};
}
render() {
//update state
//use set state everywhere besides constructor!!
return (
<div>
<input onChange={event => this.setState({term: event.target.value})}
/>
Value of the input: {this.state.term}
</div>
);
}
}
export default SearchBar;
Any Ideas as to what I am doing wrong here?

Can you confirm the following directory structure?
my_project/src/index.js
my_project/src/components/search_bar.js
It seems like your current directory structure might instead look like this:
my_project/src/index.js, my_project/components/search_bar.js

AHHH I left an 's' out of constructor... so search_bar.js was unable to compile. I have been looking at this for about an hour now...

Refs are null in Jest snapshot tests with react-test-renderer

Currently I am manually initializing Quill editor on componentDidMount and jest tests fail for me. Looks like ref value that I am getting is null in jsdom. There is and issue here: https://github.com/facebook/react/issues/7371 but looks like refs should work. Any ideas what I should check?
Component:
import React, { Component } from 'react';
import logo from './logo.svg';
import './App.css';
class App extends Component {
componentDidMount() {
console.log(this._p)
}
render() {
return (
<div className="App">
<div className="App-header">
<img src={logo} className="App-logo" alt="logo" />
<h2>Welcome to React</h2>
</div>
<p className="App-intro" ref={(c) => { this._p = c }}>
To get started, edit <code>src/App.js</code> and save to reload.
</p>
</div>
);
}
}
Test:
import React from 'react';
import ReactDOM from 'react-dom';
import App from './App';
import renderer from 'react-test-renderer'
it('snapshot testing', () => {
const tree = renderer.create(
<App />
).toJSON()
expect(tree).toMatchSnapshot()
})
As a result, console.log outputs null. But I would expect P tag

Since test renderer is not coupled to React DOM, it doesn't know anything about what refs are supposed to look like. React 15.4.0 adds the ability to mock refs for test renderer but you should provide those mocks yourself. React 15.4.0 release notes include an example of doing so.
import React from 'react';
import App from './App';
import renderer from 'react-test-renderer';
function createNodeMock(element) {
if (element.type === 'p') {
// This is your fake DOM node for <p>.
// Feel free to add any stub methods, e.g. focus() or any
// other methods necessary to prevent crashes in your components.
return {};
}
// You can return any object from this method for any type of DOM component.
// React will use it as a ref instead of a DOM node when snapshot testing.
return null;
}
it('renders correctly', () => {
const options = {createNodeMock};
// Don't forget to pass the options object!
const tree = renderer.create(<App />, options);
expect(tree).toMatchSnapshot();
});
Note that it only works with React 15.4.0 and higher.

I used Enzyme-based test from this repo to solve this issue like that:
import { shallow } from 'enzyme'
import toJson from 'enzyme-to-json'
describe('< SomeComponent />', () => {
it('renders', () => {
const wrapper = shallow(<SomeComponent />);
expect(toJson(wrapper)).toMatchSnapshot();
});
});