How do I decide whether @types/* goes into `dependencies` or `devDependencies`?

How to decide whether @types/* goes into dependencies or devDependencies? 🤔

So you're working on a TypeScript project and you want to add typings for a JavaScript library using the @types syntax. Great! But you're wondering whether these typings should be placed in the dependencies or devDependencies section of your package.json file. Don't worry, you're not alone in this confusion. In this blog post, we'll dive into this common issue and provide you with an easy solution. Let's get started! 🚀

Understanding the difference between dependencies and devDependencies 📦

Before we can make a decision, let's clarify the difference between dependencies and devDependencies.

• dependencies: These are the packages that your project relies on in production and at runtime. They include the core libraries and modules required for your application to function correctly.

• devDependencies: These are the packages that are only needed during development, not in production. They typically include tools, testing frameworks, build configurations, and type definitions.

Considerations for @types/* typings ⚙️

Now that we know the distinction between dependencies and devDependencies, let's think about the specific case of @types/* typings.

1. Are the typings required for development purposes only? If the typings are solely needed during development, such as for type checking, linting, or editor assistance, it's best to place them in devDependencies. This keeps your production dependencies clean and avoids bloating your final bundle.

2. Do the typings impact the runtime behavior of your application? If the typings are essential for the runtime operation of your application, such as when using specific libraries or APIs, they should be placed in dependencies. This ensures that the typings are included when deploying your application, as they are required for it to function correctly.

Example scenarios 🌟

Let's consider a couple of scenarios to illustrate how to decide where your @types/* typings belong:

1. Scenario 1: React typings 📚 You're developing a React application and want to add typings for the React library. Since React typings are only needed during development to improve code quality and editor experience, you should install them as a devDependency. If you were to include them in dependencies, they would unnecessarily increase your final bundle size.

2. Scenario 2: Lodash typings 🔄 You're using Lodash in your project and want to use typings to enhance type safety and development experience. However, the Lodash typings are also needed at runtime because they provide additional type information that TypeScript uses during compilation. Therefore, you should install them as a dependency.

Remember, these scenarios might not cover all possible situations, but they should give you a general idea of how to approach the decision-making process.

The final verdict: where do @types/* typings belong? ✅

After considering the criteria above, the final decision is up to you and your specific project requirements. However, as a general guideline:

• If the typings are only required during development, place them in devDependencies.

• If the typings are also needed at runtime, include them in dependencies.

Don't be confused – make an informed choice! 🎯

Deciding whether @types/* typings go into dependencies or devDependencies can be confusing, especially when there's no clear guidance available. However, by understanding the purpose of each section and considering the impact of the typings on development and runtime behavior, you can make an informed choice that suits your project's needs.

So next time you're adding typings to your TypeScript project, keep these considerations in mind to ensure your package.json file remains well-organized and your project runs smoothly.

Got any questions or additional tips? Share them in the comments below! Let's clear up the confusion and help each other build better TypeScript projects! 👇