How can I use commander (npm) with TypeScript?

Question

I have the following code on my app:

import commander = require('commander');

commander
  .option('-u, --user [user]', 'user code')
  .option('-p, --pass [pass]', 'pass code')
  .parse(process.argv);

Then I try to access:

commander.user

But I get an error (commander.d.ts from DefinitelyTyped):

user does not exist on type IExportedCommand

I tried adding this

interface IExportedCommand {
  user: string;
  pass: string;
}

But I still get the error. How can I fix this?

Answer 1

You can also do:

npm install --save-dev @types/commander

EDIT: Commander now includes its own TypeScript typings, so this should no longer be necessary.

Answer 2

Create a file commander-expansion.d.ts with the following :

declare namespace commander {
    interface IExportedCommand extends ICommand {
        user: string; 
        pass: string;
    }
}

Tip

Because I did something like this recently, recommend --auth user:password. Saves you dealing with user missing username or password. But prevents using : as a password property

¯\_(ツ)_/¯

More : https://github.com/alm-tools/alm/blob/master/src/server/commandLine.ts#L24

Answer 3

You can keep the Typescript interface within the same file.

interface InterfaceCLI extends commander.ICommand {
  user?: string
  password?: string
}

After you can define this interface to a variable after running the program.parse function.

const cli: InterfaceCLI = program.parse(process.argv)
console.log(cli.user, cli.password)

I hope this helps!