Custom Typescript Declaration files

Create in this directory your custom type definitions. For example, declaration files for untyped npm modules.

First, create some .d.ts file like ./my-npm-js-module.d.ts or using a directory with the module name ./my-npm-js-module/index.d.ts

Then create your declaration module

declare module 'my-npm-js-module' {
  // all your stuff here like interfaces, classes, external imports, etc...
}

For more info about see Typescript Module Augmentation docs.