[Bug] Wrong types for defaultValue

[Sadzurami]

Example:

import { program } from 'commander';
program.option('-n, --num', 'test num value', 10)

Result:

No overload matches this call.
  Overload 1 of 3, '(flags: string, description?: string, defaultValue?: string | boolean | string[]): Command', gave the following error.
    Argument of type '10' is not assignable to parameter of type 'string | boolean | string[]'.
  Overload 2 of 3, '(flags: string, description: string, parseArg: (value: string, previous: unknown) => unknown, defaultValue?: unknown): Command', gave the following error.
    Argument of type 'number' is not assignable to parameter of type '(value: string, previous: unknown) => unknown'.
  Overload 3 of 3, '(flags: string, description: string, regexp: RegExp, defaultValue?: string | boolean | string[]): Command', gave the following error.
    Argument of type 'number' is not assignable to parameter of type 'RegExp'.

[shadowspawn]

The TypeScript types are deliberately stricter than the JavaScript implementation to help guide users to safer patterns by default. In this case if this was silently allowed, you would have your option value being a number if it came from the default and a string if from the parsed arguments.

See similar closed PR #1792

[shadowspawn]

The Pull Request that removed multiple uses of any including for the .option() default value: #1119

[shadowspawn]

In many cases, you can get the type you want and strict types by also specifying a custom option processing function.

If that isn't a match for what you want you can also use the Option class directly and it allows any type in the .default() call:

.addOption(new Option('-n, --num <value>', 'test num value').default(10));