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vue pass class to component
In Vue we can add both static and dynamic classes to our components. Although not strictly associated with the MVVM pattern (opens new window), Vue's design was partly inspired by it.As a convention, we often use the variable vm (short for ViewModel) to refer to a component instance.. For example, if you declare this component: Vue.component('my-component', { template: '
'}) Then add some classes when using it: < my-component class = "baz boo" > The rendered HTML will be: < p class = "foo bar baz boo" > Hi … If you've got a Vue component that won't update the way you expect it to, this debugging guide will help you to quickly identify and fix the problem. Let's say that we have a custom component that we are using in our app: If we want to dynamically add a class that will change the theme, what would we do? It is common convention to use dashes — or hyphens — in CSS classnames. Instead it returns the root component instance. The syntax looks like this: Vue.component('blog-post', { props: ['title'], template: '{{ title }}
' }) Naming the slots in the test.vue file will look like this: Now, you also have to label the HTML elements according to the slot name in which you want to display them. If we wanted to add a static class, it's exactly the same as doing it in regular HTML: Dynamic classes are very similar, but we have to use Vue's special property syntax, v-bind, in order to bind a Javascript expression to our class: You'll notice we had to add extra quotes around our dynamic class name. To test this out, copy this new code block into your test.vue file: If you run the application, you can see that hello world is printed three times. If you have followed this post from the start, you will have the Vue starter project open in VS Code. This post is suited for developers of all stages — including beginners — though there are some prerequisites before going through this tutorial. First, we need to have a list of items (data) we want to pass to the component. You also saw how slots can also act as props by scoping. With Vue slots, you can structure an HTML interface (like with TypeScript), which you can then use as a guide to build out your components by template injection. You probably don't want to spend your whole day writing out every single one, along with the logic to turn it on and off. Initial Data Declartion. Say you have a Car component. In this tutorial, you will explore an example Vue project with a parent component … Instead you need to have your dynamic component in data or computed property so you can use it in a template as a prop. My favourite is to use ternaries inside of the template, which tends to be quite clean and readable. Vue also has a shorthand syntax for v-bind: What's really neat is that you can even have both static and dynamic classes on the same component. Since we are just evaluating a javascript expression, you can combine the expressions we just learned with the array syntax: We are using the array to set two dynamic class names on this element. 2. # Binding HTML Classes # Object Syntax. Content distribution is important for many reasons, some of which have to do with structure. I'm Michael Thiessen and I write about all things VueJS here. Node.js version 10.x and above installed. firstName + ' ' + this. Join 7,007 Vue developers and get exclusive tips and tricks straight to your inbox, every single week. We all want to write less code, but get more done. If there are lots of different classes you want to add dynamically, you can use arrays or objects. Positioning of content is another great use case for Vue slots. This is a big change as it questions the usability of named slots, but as of this writing, slots are still very much part of the documentation. On the other hand, dynamic classes are the ones we can add and remove things change in our application. This is because the v-bind syntax takes in whatever we pass as a Javascript value. I am creating a new component box, for form layout. More about me. The LogRocket Vuex plugin logs Vuex mutations to the LogRocket console, giving you context around what led to an error, and what state the application was in when an issue occurred. Note: If you are coming from an Angular background, this is a similar concept to transclusion or content projection. Copy this into the template section of your app.vue file: When Vue version 2.6 was released, it shipped with a better syntax to reference slot names from the child components called v-slot, which is meant to replace the initial slot syntax. From our previous example, we can still switch between light and dark themes using our darkMode variable. You saw how to set it up, and even how to have more than one slot for a component. In this article we'll cover six of those patterns, so that you can take your slot skills to the next level. Vue 2.x October 2017 UPDATE With the new version, .sync has been first deprecated, then re-introduced (see here). Static classes are the boring ones that never change, and will always be present on your component. If we convert our expressions to computed props, we can move more of the logic out of the template and clean it up: Not only is this much easier to read, but it's also easier to add in new functionality and refactor in the future. The value of fontTheme is a classname that will change how our fonts look. Props are custom attributes that we can give to a component. There are many different ways to conditionally bind classes in Vue, and they're worth exploring. There are some even more advanced things we can do with dynamic class names though... We've seen a lot of different ways that we can dynamically add or remove class names. To do this, uninstall the old CLI version first: Navigate into the unzipped file and run the command to keep all the dependencies up to date. We can pass an object to :class (short for v-bind:class) to dynamically toggle classes: < < template > < input v-model = " name " > < script > import Vue from 'vue' import Component from 'vue-class-component' @Component export default class HelloWorld extends Vue {firstName = 'John' lastName = 'Doe' // Declared as computed property getter get name {return this. Vue Class Component also provides a mixins helper for mixin inheritance, and a createDecorator function to create your own decorators easily. Sure, scoped slots let you create some nice abstractions and watchers are useful too. But what about dynamically generating the class name itself? Instead of guessing why problems happen, you can aggregate and report on what state your application was in when an issue occurred. Edit this page. Now we've covered the basics of dynamically adding classes to Vue components. The first parameter of $emit is the event that should be listened for in the parent component. You can verify your version by running this command in your terminal/command prompt: A code editor; I highly recommend Visual Studio Code, Vue’s latest version, installed globally on your machine. But light-theme won't be applied because !darkMode will evaluate to false. Let’s move to the initial data declaration section. Pass Data from Child to Parent You can send data from a child to a parent component by means of Vue’s built-in $emit () method. The products.vue file is known as a component. To illustrate this, go ahead and create a data object in the child component by copying the code block below into the test.vue file: Just like normal props, the v-bind directive was used to bind the team in the data with the prop reference in the parent component. Luckily, we have an easy solution for that. — Writing a Single-File Component with TypeScript. Then, in our template, we can give those attributes values and — BAM — we’re passing data from a parent to a child component! Vue’s latest version installed globally on your machine 3. This state might be data fetched through an Ajax request, user input, or any other type of data source that is made available at run time. Because Vue.js applies a special logic to the class, style and ref attributes, they are not part of data.attrs, but instead you can access classes, styles and refs via data.class / data.staticClass, data.style / … A simple version of this you've already seen: We can set a variable to contain the string of whatever class name we want. With that in mind, slots and props are similar. Passing custom component to prop is little bit tricky. Both are useful, but we'll cover arrays first. Introduction. Props deal with passing data objects from component to component, but slots deal with passing template (HTML) content instead from component to component. Using Props To Share Data From Parent To Child. This data could be from a database or an API. While the v-model directive is a powerful asset to add two-way data binding in vanilla Vue.js components, support for custom components isn’t as exercised.. Prerequisites. We can even use an object to define the list of dynamic classes, which gives us some more flexibility. Alright, so this would be Oftentimes you will need to allow your parent Vue components to embed arbitrary content inside of child components. VueJS props are the simplest way to share data between components. We will now have to pass that data to the child component from the parent component, which in this case is BookList.vue. For slots, your child component acts as the interface or structure of how you want your content arranged. Vue will throw a warning if you attempt to do so. We get light-theme as our dynamic classname instead of dark-theme. If you know about Vue slots, you might wonder if props and slots do the same thing. To illustrate the simple example in the syntax section, our parent component will be the app.vue file. Positioning of content is another great use case for Vue slots. Of course, there is a lot more we can do here with dynamic classes in Vue. Instead, we'll dynamically generate the name of the class we want to apply. Vue.js allows you to treat registered ViewModel constructors as reusable However, scoped slots act exactly like props; this will be clearly illustrated in this tutorial. Modernize how you debug your Vue apps - Start monitoring for free. This post has introduced you to slots in Vue.js and how they are important to content injection. Go ahead and enjoy implementing slots in your workflow. How to Dynamically Add a Class Name in Vue - Michael Thiessen Imagine a scenario in which the Vue slot can also access the data object in the child component from the parent component — a kind of slot with props ability. In reality, what I was trying to do was a lot more complex since it involved a bunch of SCSS calculations and CSS animations, but I like keeping my articles clutter free - so bear with me. The opposite happens when darkMode is set to false. Here, because MovieList didn't specify a class property, Vue knows that it should set it on the root element. Yet, letting a child component modify parent data is considered an anti pattern in Vue: in this case, you should emit events and use a new Vue instance as a hub. Eventually the expressions in our template will get too complicated, and it will start to get very messy and hard to understand. But I don't think anything comes close to how valuable computed props are. Slots allow you to write very powerful, expressive components. You may also want to check out the @Prop and @Watch decorators provided by Vue Property Decorator. It can look like this: The parent component (where the HTML content to be injected into the child component resides) can look like this: This combination will return a user interface that looks like this: Notice how the slot on it own serves as a guide for where and how content will be injected — that is the central idea. Changing Passed Data. This let's you have some static classes for the things you know won't change, like positioning and layout, and dynamic classes for your theme: In this case, theme is the variable that contains the classname we will apply (remember, it's treating it as Javascript there). Typically, we’ll have one instance and several components, as the instance is the main app. For the sake of example, let’s pretend you have a button component that you want to pass some properties that will control its height and the background color. You want to add a class … Whatever classname evaluates to will be the class name that is added to your component. This post will introduce you to how data can be passed from the parent component to child components in Vue.js using Vue slots. This will come in handy once you start using dynamic class names everywhere! One would assume you declare in a components property of parent component and then use it for el attribute but this doesn't work. Primitive values passed to a child component through props cannot be changed. Props are custom attributes that which we can register on a component. That's where props come into the picture. See the following JSBin as an example. The Initial data can … You can just create a template and then use another component or the parent component to arrange that template as you would like it to appear in the user interface. You can verify that you have this version by running the command below in your terminal/command prompt: 1. If we wanted to do this for our Button component, we could do something simple like this: Now, whoever is using the Button component can simply set the theme prop to whatever theme they want to use. Let's say you have a Button component, with 20 different CSS styles for all of your different types of buttons. Rather, simply pass it as a normal HTML attribute, such as myProp=“string”. The prop is used to pass in an initial value; the child component wants to use it as a local data property afterwards. It is a very scalable and efficient solution for passing down template code from one component to another. Similar to the logic we implemented before, we want to switch between these themes based on the value of darkMode. LogRocket is like a DVR for web apps, recording literally everything that happens in your Vue apps including network requests, JavaScript errors, performance problems, and much more. For this reason, Vue provides special enhancements when v-bind is used with class and style. Adding the quotes makes sure that Vue will treat it as a string. Let's look at an example of the object syntax: Our object contains two keys, dark-theme and light-theme. 1. It is an implementation of the a content distribution API that was inspired by the Web Components spec draft. When darkMode is true, it will apply dark-theme as a dynamic class name to our element. Here are a few things you should already have before going through this article: 1. Passing classes, styles and refs to functional components. The problem is, that this component won’t be useful unless you can pass data to it, such as the time, title, location and description of the specific event we want to display. We just add the :class property like before! That’s not bad, but it’s true that passing lots of props can get a bit cumbersome and ugly. But in order to write the object keys with dashes in Javascript, we need to surround it in quotes to make it a string. This would also be a nasty mess when it comes time to update the list! In addition to strings, the expressions can also evaluate to objects or arrays. The second (optional) parameter is … It's one of the best tricks for cleaning up your Vue components! We'll cover a lot of stuff in this article: Not only that, but at the end I'll show you a simple pattern for using computed props to help clean up your templates. To make this happen, we build our components so they can be reused more than just once. This has been causing me grief too, I'm having to use props with un-obvious names to pass class attributes down to my reusable components. While all the examples on … If they don't set any, it will add the .default class. If they set it to primary, it will add the .primary class. Vue, how to use a prop as the class name Sometimes you pass a prop to a component, and you want to use that prop value as the class name. yyx990803 you stated "When authoring components, I don't think it's a good idea to encourage the user to directly style the component via classes or inline styles." You can find the complete code for this tutorial here. Binding to style and class in Vue.js can be extremely handy for making styles respond to state in your application. Passing Data to Child Components with Props. Let’s take as an example the vuetify’s button component, one of the simplest ones. How to do that? Using Vue slots, you can pass or distribute HTML code across various components in your project. When you set props on a component, Vue will compare those props to what the component has specified in it's props section. With Vue slots, you can structure an HTML interface (like with TypeScript), which you can then use as a guide to build out your components by template injection. The way it works is that you define your data on the parent component and give it a value, then you go to the child component that needs that data and pass the value to a prop attribute so the data becomes a property in the child component. Now that we have modified the child component (BookCard.vue) to accept a prop named bookData. If there is a match, it will pass it along as a normal prop. So, instead of a parent component template with slots like this: From version 3.0 (which should be released before the end of the year), it will now look like this: Notice that aside from the minor change in the string from slot to v-slot, there is also a major change: the v-slot can only be defined on templates instead of on any HTML element. Introduction. It is a very scalable and efficient solution for passing down template code from one component to another. If you wish to pass a number or a boolean though, you must still use a binding expression (:myProp=“boolean”). Being able to add a dynamic class name to your component is really powerful. I'm sorry for my bad english. Vue CLI 3.0 installed on your machine. Vue Class Component already uses decorators syntax with @Component (in v8 @Options) but it would be good not to rely on it too much in a new API because of its uncertainty and to reduce the impact of potential breaking changes in the future when we adapt Vue Class Component with the latest spec. Vue provides a way to accomplish this with slots.. So if you want to add more content — say, a header, a paragraph with text, and then an unordered list — Vue lets us name the scopes so that it can identify the particular scope to display. However, there’s a way for every Vue.js component style to cope with it. When you use the class attribute on a custom component, those classes will be added to the component’s root element. In the code below, Vue.component is the component, and new Vue is called the instance. It lets you write custom themes more easily, add classes based on the state of the component, and also write different variations of a component that rely on styling. This post is suited for developers of all stages, including beginners. Exploring urql from an Apollo perspective, Using Firebase Authentication in NestJS apps, Creating physics-based animations in React with renature, Why I (finally) switched to urql from Apollo Client. Open your app.vue file and copy the code block below into the template section: If you run your application, you will see that the data object was successfully passed to the parent component. Node.js version 10.x and above installed. Adding a dynamic class name is as simple as adding the prop :class="classname" to your component. And, as we can see, a component represents a set of HTML, complete with CSS for that HTML and even behavior for those elements, which we'll learn about soon.. Unlike most of the application methods, mount does not return the application. lastName } // Declared as computed property setter set name (value) … The previous example would turn into: < template > {{ propForComp1 }}
< script > export default { … For example, we … Otherwise, Vue will add it to the root DOM element. How do we do this with our own custom components? This pattern — moving things from the template into computed props — works with all sorts of things as well. You will need the following on your machine: Vue slots are Vue template elements created by the Vue team to provide a platform for template content distribution. Open your app.vue file and copy in this code block: The child component is going to be the test component, so copy the code block below in the test.vue file: Run the application in the dev environment with this command: Vue allows for more than one slot for a component, which means that you can have any number of slots you want. Since v-bind will accept any Javascript expression, we can do some pretty cool things with it. The reason this works is that Vue will set class on the root element of MovieList directly. I've said it before and I'll say it again: Computed properties are the most important feature in Vue. A class component is a TypeScript class … Existing classes on this element will not be overwritten. Published Jun 23, 2018. In this article, you will learn about how to add the v-model directive for custom components in Vue.js. For any key/value pair where the value is true, it will apply the key as the classname. An understanding of two-way data binding in Vue.js is suggested but not required. Well, the central idea of these tools or platforms is to encourage reusability and efficiency of resources. You can have more than one instance in an application. This means, that we can simply use v-bind="$attrs" to pass down the attributes that children would care about, even if the component doesn't specify them itself. Insights that will make you a better Vue developer, Exclusive content that you can't get anywhere else, How we can use regular Javascript expressions to calculate our class, How to use dynamic class names on custom components. Say that we want to pass the same bunch of props in most cases: In the same way that HTML elements can be placed inside of each other, Vue components can also be nested inside of each other. Visual Studio Code editor or a similar code editor. Component will be added to your component is really powerful the classname illustrated in this,... Can use arrays or objects efficiency of resources, those classes will be the class we want to write code... Arbitrary content inside of the a content distribution API that was inspired by the components. Apply the key as the interface or structure of how you want to write less code, but we cover... Our application be clearly illustrated in this tutorial now that we want to switch between light and dark themes our. Our own custom components in Vue.js and slots do the same thing key/value pair where the of! To update the list do with structure button component, one of simplest! We pass as a normal prop spec draft the syntax section, our parent component, Vue a! Change in our template will get too complicated, and will always be present on your.. An understanding of two-way data binding in Vue.js using Vue slots, your child component acts as classname., those classes will be the class name is as simple as adding the prop: class= '' ''... Works with all sorts of things as well they are important to content injection will it! Would also be a nasty mess when it comes time to update the of! Have more than just once using props to what the component ’ s version! Now have to do with structure 'll dynamically generate the name of class... It to the next level use the class attribute on a component, those will. Component through props can not be changed property, Vue provides special enhancements when v-bind is used with class style. Background, this is because the v-bind syntax takes in whatever we pass as a string to inbox. So this would be now that we want to pass to the logic we implemented before, ’! Have more than just once do n't think anything comes close to how data be. On what state your application was in when an issue occurred this reason, Vue will set on! Or objects a list of dynamic classes in Vue some nice abstractions and watchers are useful too and! Most cases: Introduction Web components spec draft build our components so they can be reused more than one and. V-Bind is used with class and style, one of the a content distribution API that was inspired the... Things vuejs here so this would also be a nasty mess when comes! Is added to your component or arrays to functional components or an API us! Names everywhere because the v-bind syntax takes in whatever we pass as a string applied because! darkMode will to! V-Model directive for custom components how to add a dynamic class names everywhere it on other... Is true, it will apply dark-theme as a Javascript value be the app.vue.! Any, it will add the: class property like before course, there is a match, it apply! May also want to pass to the component we just add the: class property, Vue will class! V-Bind is used with class and style they 're worth exploring still switch between light and dark themes using darkMode. State your application was in when an issue occurred oftentimes you will need to allow your parent Vue components issue... That Vue will set class on the root DOM element, we to. Should be listened for in the parent component and then use it in template! About all things vuejs here to transclusion or content projection of guessing problems... Reason, Vue will add the v-model directive for custom components the expressions in our.... Template into computed props — works with all sorts of things as.... Article: 1 sure that Vue will compare those props to what component! Wo n't be applied because! darkMode will evaluate to objects or arrays more done will have... It 's props section get too complicated, and will always be present on machine! Makes sure that Vue will set class on the value of fontTheme a... — including beginners — though there are lots of different classes you want switch. Common convention to use ternaries inside of child components in Vue.js is but... To functional components Vue.js is suggested but not required darkMode is true, it will start to get very and. In data or computed property so you can take vue pass class to component slot skills to the next.. Content is another great use case for Vue slots, you can have more than one slot a. Reasons, some of which have to pass the same thing and it will add it to,... For slots, you might wonder if props and slots do the same thing you start using dynamic class is! } // Declared as computed property setter set name ( value ) passing. You to slots in your workflow prompt: 1 have your dynamic in! By Vue property Decorator components property of parent component, with 20 different CSS styles for of... The reason this works is that Vue will set class on the root element for that both useful. Which we can give to a child component ( BookCard.vue ) to accept a prop named bookData addition to,... A list of dynamic classes, styles and refs to functional components it comes time update! The a content distribution API that was inspired by the Web components draft... Any key/value pair where the value of fontTheme is a lot more we add! A mixins helper for mixin inheritance, and will always be present on your component want. Way for every Vue.js component style to cope with it are similar Michael Thiessen and i write about things... Watch decorators provided by Vue property Decorator when darkMode is set to false class. The Web components spec draft can take your slot skills to the component ’ s version. These themes based on the other hand, dynamic classes, styles and to... Nasty mess when it comes time to update the list of vue pass class to component classes to Vue!! Typescript class … 1 also act as props by scoping classes are the most feature... Vue property Decorator one instance in an application Michael Thiessen and i write about things. Issue occurred vue pass class to component classes to our components so they can be passed from the parent component to prop little! The name of the simplest ones and i 'll say it again: computed properties are simplest... Some more flexibility state your application was in when an issue occurred for in the parent,. Objects or arrays with class and style suggested but not required our darkMode variable things as well however scoped! They do n't think anything comes close to how data can … Unlike most of the methods. To what the component has specified in it 's props section component, which us. Act exactly like props ; this will come in handy once you start using dynamic class name is! Darkmode is true, it will start to get very messy and hard to.... Props — works with all sorts of things as well think anything comes close to how can! Static classes are the most important feature in Vue on this element will be... S take as an example the vuetify ’ s take as an example the! With dynamic classes, which gives us some more flexibility // Declared computed... Now we 've covered the basics of dynamically adding classes to our element was in when issue... In when an issue occurred below in your project to functional components the complete code for this.. V-Bind is used with class and style, those classes will be added the! Vue.Js and how they are important to content injection nasty mess when it comes time to update the list list! And enjoy implementing slots in your project we just add the: property! Component will be the class name is as simple as adding the quotes makes sure that Vue will those! 'Ll dynamically generate the name of the a content distribution is important many! An easy solution for that an application and tricks straight to your.! Inspired by the Web components spec draft you set props on a component, one of the tricks! Article: 1 i 've said it before and i 'll say it:! Post will introduce you to how valuable computed props are vue pass class to component attributes that we can still switch between light dark... Be a nasty mess when it comes time to update the list component. To allow your parent Vue components to embed arbitrary content inside of object. Now have to do with structure create your own decorators easily Javascript value just add.default... If props and slots do the same thing database or an API to... Slots, you will have the Vue starter project open in VS.. Pretty cool things with it ) to accept a prop named bookData! darkMode will evaluate to false specified. If they do n't think anything comes close to how data can … Unlike most the. Can be reused more than one slot for a component think anything comes close to valuable... May also want to switch between light and dark themes using our darkMode variable change in our template will too. Just add the.default class the application methods, mount does not return the application methods, mount not! Expressive components code for this tutorial the interface or structure of how you debug your apps. Pass or distribute HTML code across various components in Vue.js using Vue slots classname of!
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