Vue.js 3.0 Tutorial

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Vue.js 3.0 Style Guide

Vue 3.0 Style Guide

Vue 3.0 Data Options

In Vue 3.0, the data option is used for declaring the reactive data for a component. This is typically done by returning an object from the data function where the object contains the initial state for the component. Each key in the object will then be made reactive by Vue and will be able to trigger view updates when it changes.

Here's a basic example:

<template>
  <div>
    <p>{{ message }}</p>
    <button @click="changeMessage">Change Message</button>
  </div>
</template>

<script>
export default {
  data() {
    return {
      message: 'Hello, Vue!',
    };
  },
  methods: {
    changeMessage() {
      this.message = 'Hello, World!';
    },
  },
};
</script>

In this example, message is a reactive data property. When the changeMessage method is called, it changes the value of message, and this change will automatically cause the view to update and display the new message.

Remember that the data function should always return a new object. This is important to ensure that each instance of a component maintains its own independent copy of the data:

data() {
  return {
    message: 'Hello, Vue!',
  };
},

If we were to return a shared object instead, then changes in one component instance would affect all other instances, which is usually not what we want.

Note: In Vue 3.0, the Composition API was introduced as an alternative way to manage component logic and state. Instead of using the data option, you might choose to use the setup function and the ref or reactive functions from vue to declare reactive data with the Composition API. The choice between the Options API (which includes data) and the Composition API depends on your personal preference and the specific needs of your project.

Vue 3.0 Reactive Data Properties:

Vue 3.0 introduces the Composition API, allowing reactive data properties using the ref function.

<!-- ReactiveDataProperties.vue -->
<template>
  <div>{{ myData.value }}</div>
</template>

<script>
import { ref } from 'vue';

export default {
  setup() {
    const myData = ref('Reactive data');

    return {
      myData,
    };
  },
};
</script>

Vue 3.0 Using Data Option in Composition API:

In the Composition API, use the data option to define reactive data properties.

<!-- UsingDataOption.vue -->
<template>
  <div>{{ myData }}</div>
</template>

<script>
import { ref } from 'vue';

export default {
  setup() {
    const myData = ref('Data from data option');

    return {
      myData,
    };
  },
};
</script>

Vue 3.0 Data Option vs Ref in Components:

Compare using the data option and ref for defining data in Vue components.

<!-- DataOptionVsRef.vue -->
<template>
  <div>{{ dataOptionValue }} | {{ refValue }}</div>
</template>

<script>
import { ref } from 'vue';

export default {
  data() {
    return {
      dataOptionValue: 'Data from data option',
    };
  },
  setup() {
    const refValue = ref('Data from ref');

    return {
      refValue,
    };
  },
};
</script>

Vue 3.0 Defining Data in Single-File Components:

Define data properties in single-file components using the data option.

<!-- DefiningData.vue -->
<template>
  <div>{{ myData }}</div>
</template>

<script>
export default {
  data() {
    return {
      myData: 'Defined in data option',
    };
  },
};
</script>

Vue 3.0 Data Option and Reactivity System:

Explore how the data option interacts with Vue 3.0's reactivity system.

<!-- DataReactivity.vue -->
<template>
  <div>{{ myData }}</div>
</template>

<script>
export default {
  data() {
    return {
      myData: 'Reactive data',
    };
  },
};
</script>

Vue 3.0 Accessing Data Properties in Templates:

Access and display data properties in Vue 3.0 templates.

<!-- AccessingDataInTemplates.vue -->
<template>
  <div>{{ myData }}</div>
</template>

<script>
export default {
  data() {
    return {
      myData: 'Accessed in template',
    };
  },
};
</script>

Vue 3.0 Data Option and Component State:

Use the data option to manage component state in Vue 3.0.

<!-- ComponentState.vue -->
<template>
  <div>{{ count }}</div>
</template>

<script>
export default {
  data() {
    return {
      count: 0,
    };
  },
};
</script>

Vue 3.0 Data Lifecycle in Components:

Understand the lifecycle of data properties in Vue 3.0 components.

<!-- DataLifecycle.vue -->
<template>
  <div>{{ myData }}</div>
</template>

<script>
export default {
  data() {
    console.log('Data initialized');
    return {
      myData: 'Lifecycle example',
    };
  },
  created() {
    console.log('Component created');
  },
};
</script>

Vue 3.0 Structuring Data in Vue Components:

Organize and structure data properties within Vue components.

<!-- StructuringData.vue -->
<template>
  <div>{{ user.name }} | {{ user.age }}</div>
</template>

<script>
export default {
  data() {
    return {
      user: {
        name: 'John Doe',
        age: 25,
      },
    };
  },
};
</script>