Chapter 6. Types Declarations and @types
Dependency management can be confusing in any language, and TypeScript is no exception. This chapter will help you build a mental model for how dependencies work in TypeScript and show you how to work through some of the issues that can come up with them. It will also help you craft your own type declaration files to publish and share with others. By writing great type declarations, you can help not just your own project but the entire TypeScript community.
Item 45: Put TypeScript and @types in devDependencies
npm draws a distinction between a few types of dependencies, each of which goes in a separate section of package.json:
lodashat runtime, then it should go in
dependencies. When you publish your code on npm and another user installs it, it will also install these dependencies. (These are known as transitive dependencies.)
These packages are used to develop and test your code but are not required at runtime. Your test framework would be an example of a
dependencies, these are not installed transitively with your packages.
These are packages that you require at runtime but ...