Files F103826616

argument.js
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Created: Tue, Mar 4, 23:44

argument.js
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	const { InvalidArgumentError } = require('./error.js');

	// @ts-check

	class Argument {
	/**
	* Initialize a new command argument with the given name and description.
	* The default is that the argument is required, and you can explicitly
	* indicate this with <> around the name. Put [] around the name for an optional argument.
	*
	* @param {string} name
	* @param {string} [description]
	*/

	constructor(name, description) {
	this.description = description \|\| '';
	this.variadic = false;
	this.parseArg = undefined;
	this.defaultValue = undefined;
	this.defaultValueDescription = undefined;
	this.argChoices = undefined;

	switch (name[0]) {
	case '<': // e.g. <required>
	this.required = true;
	this._name = name.slice(1, -1);
	break;
	case '[': // e.g. [optional]
	this.required = false;
	this._name = name.slice(1, -1);
	break;
	default:
	this.required = true;
	this._name = name;
	break;
	}

	if (this._name.length > 3 && this._name.slice(-3) === '...') {
	this.variadic = true;
	this._name = this._name.slice(0, -3);
	}
	}

	/**
	* Return argument name.
	*
	* @return {string}
	*/

	name() {
	return this._name;
	};

	/**
	* @api private
	*/

	_concatValue(value, previous) {
	if (previous === this.defaultValue \|\| !Array.isArray(previous)) {
	return [value];
	}

	return previous.concat(value);
	}

	/**
	* Set the default value, and optionally supply the description to be displayed in the help.
	*
	* @param {any} value
	* @param {string} [description]
	* @return {Argument}
	*/

	default(value, description) {
	this.defaultValue = value;
	this.defaultValueDescription = description;
	return this;
	};

	/**
	* Set the custom handler for processing CLI command arguments into argument values.
	*
	* @param {Function} [fn]
	* @return {Argument}
	*/

	argParser(fn) {
	this.parseArg = fn;
	return this;
	};

	/**
	* Only allow option value to be one of choices.
	*
	* @param {string[]} values
	* @return {Argument}
	*/

	choices(values) {
	this.argChoices = values;
	this.parseArg = (arg, previous) => {
	if (!values.includes(arg)) {
	throw new InvalidArgumentError(`Allowed choices are ${values.join(', ')}.`);
	}
	if (this.variadic) {
	return this._concatValue(arg, previous);
	}
	return arg;
	};
	return this;
	};

	/**
	* Make option-argument required.
	*/
	argRequired() {
	this.required = true;
	return this;
	}

	/**
	* Make option-argument optional.
	*/
	argOptional() {
	this.required = false;
	return this;
	}
	}

	/**
	* Takes an argument and returns its human readable equivalent for help usage.
	*
	* @param {Argument} arg
	* @return {string}
	* @api private
	*/

	function humanReadableArgName(arg) {
	const nameOutput = arg.name() + (arg.variadic === true ? '...' : '');

	return arg.required
	? '<' + nameOutput + '>'
	: '[' + nameOutput + ']';
	}

	exports.Argument = Argument;
	exports.humanReadableArgName = humanReadableArgName;

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