Add options

Options are the named flags of your CLI (--opt, -o). Declare them with addOptions, keyed by their long name.

cli.addOptions({
  opt: {
    short: "o",
    type: "string",
    default: "test",
    description: "an option for test",
  },
});

String vs boolean options

The type field decides how an option is parsed and what value your action receives:

cli.addOptions({
  name: { type: "string" },   // opts.name is a string
  force: { type: "boolean" }, // opts.force is a boolean
});

type defaults to "string" when omitted. The value type is inferred into the action callback, so opts.force is a boolean and opts.name is a string.

Add a shorthand

Set short to expose a single-character alias:

cli.addOptions({ output: { short: "o", type: "string" } });

$ mycli --output file.txt
$ mycli -o file.txt
$ mycli -o=file.txt

Boolean shorthands can be combined: -abc sets three boolean flags at once, and -ab value sets two booleans plus a trailing value for the last flag.

Provide a default value

cli.addOptions({
  level: { type: "string", default: "info" },
  color: { type: "boolean", default: true },
});

If the user doesn't pass the option, opts.level is "info" and opts.color is true. When you give no default, a string option falls back to "" and a boolean to false.

TIP

Defaults are type-checked against type: a "boolean" option only accepts a boolean default, a "string" option only a string default.

Make an option optional

By default every declared option is present in opts (with its default). Mark an option optional: true to omit it entirely when the user doesn't pass it:

cli.addOptions({
  tag: { type: "string", optional: true },
});

Now opts.tag only exists when the user actually passes --tag. Use this for options where "not provided" is meaningfully different from "default value".

Passing values on the command line

Form	Example	Result
Long, separate	--opt value	opts.opt = "value"
Long, with =	--opt=value	opts.opt = "value"
Long boolean	--force	opts.force = true
Short, separate	-o value	opts.opt = "value"
Short, with =	-o=value	opts.opt = "value"
Combined booleans	-abc	three booleans set to true

See Parsing rules for the exact algorithm.