A validation error is thrown when the command is wrongly used by the user. For example: If the user passes some invalid options or arguments to the command.

Boolean type handler. Excepts true, false, 1, 0

Integer type handler. Excepts any integer value.

Number type handler. Excepts any numeric value.

String type handler. Excepts any value.

Parse command line arguments.

Options for a flag argument.

Argument parsing informations.

Flag options.

Parse result. The parse context will be returned by the parseFlags method and can be also passed as first argument to the parseFlags method.

Parser options.

Available build-in argument types.

Default flag value or a callback method that returns the default value.

Default value callback function to lazy load the default value.

Parse method for custom types. Gets the raw user input passed as argument and returns the parsed value.

A callback method for custom processing or mapping of flag values.