Use 'namespace' instead of 'module' to declare custom TypeScript
If you use any of the above answers and are using a newer version of Typescript you'll get a nag about using "module". You should consider namespace instead.
In order to satisfy the requirement here you'll actually need more than extending the Global interface. You'll also need to create a constant with the type as well if you want it to be accessible directly from the "globalThis" context.
NOTE: while the OP asked about an object literal the process is the same as you see here below. Rather than the "Debug" type being a function you would simply define the interface as need, then change "debug:" to myConfig or whatever you wish.
// typically I'll store the below in something like "typings.d.ts"
// this is because, at least typically, these overrides tend to
// be minimal in nature. You could break them up and Typescript
// will pick them up if you wish.
// Augmentations for the global scope can only be directly nested
// in external modules or ambient module declarations.
export {}
declare global {
// Definition or type for the function.
type Debug = (label: string) => (message: any, ...args: any[]) => void
// If defining an object you might do something like this
// interface IConfig { a: number, b: number }
// Extend the Global interface for the NodeJS namespace.
namespace NodeJS {
interface Global {
// Reference our above type,
// this allows global.debug to be used anywhere in our code.
debug: Debug
}
}
// This allows us to simply call debug('some_label')('some debug message')
// from anywhere in our code.
const debug: Debug
}
How the above might be used
For completeness in this example all we did was define a global so we can log a simple debug message. Here's how we'd bind the method to our global context.
global.debug = (label: string) => (message: any, ...args: any[]) => console.log(message, ...args)
We can also call our global debug method directly:
debug('express')(`${req.method}: ${req.url}`)
