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Understanding the basics of Vue and TypeScript

Posted on:January 24, 2023

If you want to know how to setup your Vue3 project head over here.

When working with Vue and TypeScript, components are defined as classes that extend the Vue object. Each component class has a data object, which is used to define the component’s state. In TypeScript, you can use interfaces to define the shape of this object, which can help catch errors early and improve code readability.

Here is an example of a simple Vue component written in TypeScript:

<template>
  <div>
    <h1>Hello {{ name }}!</h1>
  </div>
</template>

<script lang="ts">
import { defineComponent, PropType } from 'vue';

interface Props {
  name: string
}

export default defineComponent<Props>({
  name: 'Hello',
  props: {
    name: {
      type: String as PropType<string>,
      required: true
    }
  }
});
</script>

In this example, we have defined an interface called Props which defines the shape of the props object for this component. We also have added the lang="ts" in the script tag to indicate that this file is written in TypeScript.

You can also use TypeScript decorators to define the properties and methods of a Vue component. Decorators are a way to add meta-data to a class, which can be used to configure the behavior of the class at runtime.

Here’s an example of how you can use the @Prop decorator to define the name prop of the Hello component:

<script lang="ts">
import { defineComponent, Prop } from 'vue';

export default defineComponent({
name: 'Hello',
props: {
	name: {
		type: String,
		required: true
	}
},
setup(props) {
// Use the @Prop decorator to define a property
@Prop({ type: String, required: true })
name!: string;
}
});
</script>

In this example, we are using the @Prop decorator to define the name property of the component. The @Prop decorator takes an object that defines the prop’s options, such as its type and whether or not it is required.

Using TypeScript’s static type checking

One of the main benefits of using TypeScript with Vue is the improved static type checking it provides. TypeScript’s type checking allows you to catch errors early, before they make it to production, and make your code more readable and maintainable.

For example, if you try to pass a number to the name prop in the Hello component, TypeScript will give you an error message, telling you that a number is not assignable to a string.

<template>
  <Hello name={123} />
</template>
Error: Type '{ name: number; }' is not assignable to type '{ name: string; }'.
  Types of property 'name' are incompatible.
    Type 'number' is not assignable to type 'string'.

Additionally, you can use TypeScript’s interfaces and decorators to define the shape of your component’s data and props, making it easier to understand the component’s API and catch errors early.

Working with TypeScript’s enhanced IntelliSense

Another benefit of using TypeScript with Vue is the improved IntelliSense it provides. IntelliSense is a feature of many code editors that provides autocompletion, parameter info, and other code hints to help you write code more quickly and accurately.

When working with Vue and TypeScript, you can use IntelliSense to see the available props and methods of a component, and to see the types of the data you are working with. This can help you write code more quickly and accurately, and can also help you find and fix errors early in the development process.

Conclusion

Vue.js and TypeScript are a powerful combination that can help you build more reliable, maintainable, and scalable web applications. By using TypeScript’s static type checking and enhanced IntelliSense, you can catch errors early, make your code more readable and maintainable, and improve your development workflow.

Additional resources:

This is a basic introduction on how to use Vue.js with TypeScript, there are many more concepts, features and best practices you can learn and implement to make your application more robust and scalable. I hope this article has provided a good starting point for you to begin your journey with Vue.js and TypeScript.