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.

Flag argument definition.

Type details.

Flag options.

Result of the parseFlags method.

Parser options.

Available build-in argument types.

Default flag value

Custom type handler/parser.

Value handler for custom value processing.