Vue 3 has been released on Monday, February 7, 2022. Since the release of Vue 3 the ecosystem got a boost (for example with Vite) and the composition API has been introduced. In this article I will explain some core concepts of the composition API.

What is the composition API?

With the arrival of Vue 3 we can declare components with the options API (old way) or the composition API (new way). The composition API is a set of APIs that allows us to author Vue components using imported functions instead of declaring options.

With the composition API the Vue components are more structured and readable, this can be very helpful especially when components grow. The following image displays more structured components.

According to the official Vue documentation, the most important benefits are:

Better reusability of logic;
More flexible code organization;
Better type inference;
Smaller production bundle and less overhead.

Setup

With the composition API we can declare our Vue template in 2 different ways:

Method 1:

<script setup>const aProperty: string = 'Test';</script>

Method 2:

<script>
    export default {
        setup() {
            const state = reactive({ aProperty: 'Test' });

            return {
                state
            }
        }
    }
</script>

Both methods are working in practice most developer use method 1, it's more readable and less code is needed.

Hooks

The composition API is using hooks instead of integrated functions. With the options API we had to define integrated functions like this:

export default {
  mounted() {
    //Logic
  },

  data() {
    //Data
  },

  watch: {
    //Watch data
  },
}

With the composition API we can use hooks for this:

onMounted(() => {
  //Logic
})

const dataProperty: string = ref('')

watch(() => {
  //Watch data
})

Props

Vue 3 has been rewritten in Typescript. The integration of Vue in our TypeScript application is now more smooth since Vue 3 is rewritten in TypeScript. Props are a good example of this. With the options API:

props: {
    dogNames: {
        type: Array,
        default: []
    }
}

In Vue 2 you could already define a type, but this was still quite limited. You now have the option to use interfaces. With the composition API:

interface Props {
  dogNames: Array<String>
}

let props = withDefaults(defineProps<Props>(), {
  dogNames: [],
})

Events

When dispatching events to our parent components we notice the better Typescript support as well. Types can be declared so the developer knows if an incorrect value is being passed. Composition API:

const emit = defineEmits<{
  (event: 'dogNames', value: Array<string>): void
}>()

emit('dogNames', ['Snuffel'])

With the options API:

$emit('dogNames', ['Snuffel'])

Code reusage with hooks

With the options API duplicate code is prevented with mixins. When using multiple mixins you quickly lose the overview and are often wondering where data or logic comes from. With the composition API we can use our own hooks for this.

const useGetPreferences = () => {
  return useQuery(['Preference'], async () =>
    PreferencesService.getPreferences().then(({ data }) => data)
  )
}

export { useGetPreferences }

It's used like this:

const { data: preferences } = useGetPreferences()

With the options API:

var mixin = {
  methods: {
    useGetPreferences() {
      return useQuery(['Preference'], async () =>
        PreferencesService.getPreferences().then(({ data }) => data)
      )
    },
  },
}

It's used like this:

new Vue({
  mixins: [mixin],
})

Composition API and options API together

Maybe you are wondering if it is possible to use these API's together? Yes, that's possible! If you want to migrate a project to the composition api, this is very useful. However, for the future, the composition API will become the standard.

Final thoughts

Vue 3 has been a huge update compared to Vue 2. You could almost see it as a new framework rather than an update. Within iO, a number of projects are now done in Vue 3, in which I participate. In the beginning I had to get used to the new structure of Vue and the composition API. Now I see the benefits more and more, and understand why this update was necessary. Especially the Typescript integration is very good, and with hooks we reuse our code more easily and is it more readable.

Upcoming events

Drupal CMS Launch Party
Zoals sommigen misschien weten wordt op 15 Januari een nieuwe distributie van Drupal gelanceerd. Namelijk Drupal CMS (ook wel bekend als Starshot). Om dit te vieren gaan we op onze campus een klein eventje organiseren. We gaan die dag samen de livestream volgen waarbij het product gelanceerd wordt. De agenda is als volgt: 17u – 18u30: Drupal CMS livestream met taart 18u30 – 19u00: Versteld staan van de functionaliteiten 19u – 20u: Pizza eten en verder versteld staan van de functionaliteiten Laat ons zeker weten of je komt of niet door de invite te accepteren! Tot dan!
January 15 | Coven of Wisdom Herentals
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Coven of Wisdom - Herentals - Winter `24 edition
Worstelen jij en je team met het bouwen van schaalbare digitale ecosystemen of zit je vast in een props hell met React of in een ander framework? Kom naar onze meetup waar ervaren sprekers hun inzichten en ervaringen delen over het bouwen van robuuste en flexibele applicaties. Schrijf je in voor een avond vol kennis, heerlijk eten en een mix van creativiteit en technologie! 🚀 18:00 – 🚪 Deuren open 18:15 – 🍕 Food & drinks 19:00 – 📢 Building a Mature Digital Ecosystem - Maarten Heip 20:00 – 🍹 Kleine pauze 20:15 – 📢 Compound Components: A Better Way to Build React Components - Sead Memic 21:00 – 🙋‍♀️ Drinks 22:00 – 🍻 Tot de volgende keer? Tijdens deze meetup gaan we dieper in op het bouwen van digitale ecosystemen en het creëren van herbruikbare React componenten. Maarten deelt zijn expertise over het ontwikkelen van een volwassen digitale infrastructuur, terwijl Sead je laat zien hoe je 'From Props Hell to Component Heaven' kunt gaan door het gebruik van Compound Components. Ze delen praktische inzichten die je direct kunt toepassen in je eigen projecten. 📍 Waar? Je vindt ons bij iO Herentals - Zavelheide 15, Herentals. Volg bij aankomst de borden 'meetup' vanaf de receptie. 🎫 Schrijf je in! De plaatsen zijn beperkt, dus RSVP is noodzakelijk. Dit helpt ons ook om de juiste hoeveelheid eten en drinken te voorzien - we willen natuurlijk niet dat iemand met een lege maag naar huis gaat! 😋 Over iO Wij zijn iO: een groeiend team van experts die end-to-end-diensten aanbieden voor communicatie en digitale transformatie. We denken groot en werken lokaal. Aan strategie, creatie, content, marketing en technologie. In nauwe samenwerking met onze klanten om hun merken te versterken, hun digitale systemen te verbeteren en hun toekomstbestendige groei veilig te stellen. We helpen klanten niet alleen hun zakelijke doelen te bereiken. Samen verkennen en benutten we de eindeloze mogelijkheden die markten in constante verandering bieden. De springplank voor die visie is talent. Onze campus is onze broedplaats voor innovatie, die een omgeving creëert die talent de ruimte en stimulans geeft die het nodig heeft om te ontkiemen, te ontwikkelen en te floreren. Want werken aan de infinite opportunities van morgen, dat doen we vandaag.
December 12 | Coven of Wisdom Herentals
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The Test Automation Meetup
PLEASE RSVP SO THAT WE KNOW HOW MUCH FOOD WE WILL NEED Test automation is a cornerstone of effective software development. It's about creating robust, predictable test suites that enhance quality and reliability. By diving into automation, you're architecting systems that ensure consistency and catch issues early. This expertise not only improves the development process but also broadens your skillset, making you a more versatile team member. Whether you're a developer looking to enhance your testing skills or a QA professional aiming to dive deeper into automation, RSVP for an evening of learning, delicious food, and the fusion of coding and quality assurance! 🚀🚀 18:00 – 🚪 Doors open to the public 18:15 – 🍕 Let’s eat 19:00 – 📢 First round of Talks 19:45 – 🍹 Small break 20:00 – 📢 Second round of Talks 20:45 – 🍻 Drinks 21:00 – 🙋‍♀️ See you next time? First Round of Talks: The Power of Cross-browser Component Testing - Clarke Verdel, SR. Front-end Developer at iO How can you use Component Testing to ensure consistency cross-browser? Overcoming challenges in Visual Regression Testing - Sander van Surksum, Pagespeed | Web Performance Consultant and Sannie Kwakman, Freelance Full-stack Developer How can you overcome the challenges when setting up Visual Regression Testing? Second Round of Talks: Omg who wrote this **** code!? - Erwin Heitzman, SR. Test Automation Engineer at Rabobank How can tests help you and your team? Beyond the Unit Test - Christian Würthner, SR. Android Developer at iO How can you do advanced automated testing for, for instance, biometrics? RSVP now to secure your spot, and let's explore the fascinating world of test automation together!
December 11 | Coven of Wisdom - Amsterdam
Go to page for The Test Automation Meetup

Vue 3 composition API in a nutshell

What is the composition API?

Setup

Hooks

Props

Events

Code reusage with hooks

Composition API and options API together

Final thoughts

Upcoming events

Drupal CMS Launch Party

Coven of Wisdom - Herentals - Winter `24 edition

The Test Automation Meetup

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