feat: support enum arg type

playground/hello.ts

@@ -17,9 +17,16 @@ const command = defineCommand({
  type: "boolean",
  description: "Use friendly greeting",
  },
+ adjective: {
+ type: "enum",
+ description: "Adjective to use in greeting",
+ options: ["awesome", "cool", "nice"],
+ default: "awesome",
+ require: false,
+ }
  },
  run({ args }) {
- consola.log(`${args.friendly ? "Hi" : "Greetings"} ${args.name}!`);
+ consola.log(`${args.friendly ? "Hi" : "Greetings"} ${args.adjective} ${args.name}!`);
  },
 });
 

src/args.ts

@@ -10,6 +10,7 @@ export function parseArgs<T extends ArgsDef = ArgsDef>(
  const parseOptions = {
  boolean: [] as string[],
  string: [] as string[],
+ enum: [] as (number | string)[],
  mixed: [] as string[],
  alias: {} as Record<string, string | string[]>,
  default: {} as Record<string, boolean | string>,
@@ -21,11 +22,15 @@ export function parseArgs<T extends ArgsDef = ArgsDef>(
  if (arg.type === "positional") {
  continue;
  }
+ // eslint-disable-next-line unicorn/prefer-switch
  if (arg.type === "string") {
  parseOptions.string.push(arg.name);
  } else if (arg.type === "boolean") {
  parseOptions.boolean.push(arg.name);
+ } else if (arg.type === "enum") {
+ parseOptions.enum.push(...(arg.options || []));
  }
+
  if (arg.default !== undefined) {
  parseOptions.default[arg.name] = arg.default;
  }
@@ -56,6 +61,19 @@ export function parseArgs<T extends ArgsDef = ArgsDef>(
  } else {
  parsedArgsProxy[arg.name] = arg.default;
  }
+ } else if (arg.type === "enum") {
+ const argument = parsedArgsProxy[arg.name];
+ const options = arg.options || [];
+ if (
+ argument !== undefined &&
+ options.length > 0 &&
+ !options.includes(argument)
+ ) {
+ throw new CLIError(
+ `Invalid value for argument: \`--${arg.name}\` (\`${argument}\`). Expected one of: ${options.map((o) => `\`${o}\``).join(", ")}.`,
+ "EARG",
+ );
+ }
  } else if (arg.required && parsedArgsProxy[arg.name] === undefined) {
  throw new CLIError(`Missing required argument: --${arg.name}`, "EARG");
  }

src/types.ts

@@ -1,6 +1,6 @@
 // ----- Args -----
 
-export type ArgType = "boolean" | "string" | "positional" | undefined;
+export type ArgType = "boolean" | "string" | "positional" | "enum" | undefined;
 
 export type _ArgDef<T extends ArgType, VT extends boolean | string> = {
  type?: T;
@@ -9,12 +9,21 @@ export type _ArgDef<T extends ArgType, VT extends boolean | string> = {
  alias?: string | string[];
  default?: VT;
  required?: boolean;
+ options?: (string | number)[];
 };
 
-export type BooleanArgDef = _ArgDef<"boolean", boolean>;
-export type StringArgDef = _ArgDef<"string", string>;
-export type PositionalArgDef = Omit<_ArgDef<"positional", string>, "alias">;
-export type ArgDef = BooleanArgDef | StringArgDef | PositionalArgDef;
+export type BooleanArgDef = Omit<_ArgDef<"boolean", boolean>, "options">;
+export type StringArgDef = Omit<_ArgDef<"string", string>, "options">;
+export type PositionalArgDef = Omit<
+ _ArgDef<"positional", string>,
+ "alias" | "options"
+>;
+export type EnumArgDef = _ArgDef<"enum", string>;
+export type ArgDef =
+ | BooleanArgDef
+ | StringArgDef
+ | PositionalArgDef
+ | EnumArgDef;
 export type ArgsDef = Record<string, ArgDef>;
 export type Arg = ArgDef & { name: string; alias: string[] };
 
@@ -34,6 +43,14 @@ export type ParsedArgs<T extends ArgsDef = ArgsDef> = { _: string[] } & Record<
  }[keyof T],
  boolean
  > &
+ Record<
+ {
+ [K in keyof T]: T[K] extends { type: "enum" } ? K : never;
+ }[keyof T],
+ {
+ [K in keyof T]: T[K] extends { options: infer U } ? U : never;
+ }[keyof T]
+ > &
  Record<string, string | boolean | string[]>;
 
 // ----- Command -----

src/usage.ts

@@ -59,6 +59,9 @@ export async function renderUsage<T extends ArgsDef = ArgsDef>(
  ? `=${
  arg.valueHint ? `<${arg.valueHint}>` : `"${arg.default || ""}"`
  }`
+ : "") +
+ (arg.type === "enum" && arg.options
+ ? `=<${arg.options.join("|")}>`
  : "");
  argLines.push([
  "`" + argStr + (isRequired ? " (required)" : "") + "`",