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const flagSymbol = Symbol('arg flag');
class ArgError extends Error { constructor(msg, code) { super(msg); this.name = 'ArgError'; this.code = code;
Object.setPrototypeOf(this, ArgError.prototype); } }
function arg( opts, { argv = process.argv.slice(2), permissive = false, stopAtPositional = false } = {} ) { if (!opts) { throw new ArgError( 'argument specification object is required', 'ARG_CONFIG_NO_SPEC' ); }
const result = { _: [] };
const aliases = {}; const handlers = {};
for (const key of Object.keys(opts)) { if (!key) { throw new ArgError( 'argument key cannot be an empty string', 'ARG_CONFIG_EMPTY_KEY' ); }
if (key[0] !== '-') { throw new ArgError( `argument key must start with '-' but found: '${key}'`, 'ARG_CONFIG_NONOPT_KEY' ); }
if (key.length === 1) { throw new ArgError( `argument key must have a name; singular '-' keys are not allowed: ${key}`, 'ARG_CONFIG_NONAME_KEY' ); }
if (typeof opts[key] === 'string') { aliases[key] = opts[key]; continue; }
let type = opts[key]; let isFlag = false;
if ( Array.isArray(type) && type.length === 1 && typeof type[0] === 'function' ) { const [fn] = type; type = (value, name, prev = []) => { prev.push(fn(value, name, prev[prev.length - 1])); return prev; }; isFlag = fn === Boolean || fn[flagSymbol] === true; } else if (typeof type === 'function') { isFlag = type === Boolean || type[flagSymbol] === true; } else { throw new ArgError( `type missing or not a function or valid array type: ${key}`, 'ARG_CONFIG_VAD_TYPE' ); }
if (key[1] !== '-' && key.length > 2) { throw new ArgError( `short argument keys (with a single hyphen) must have only one character: ${key}`, 'ARG_CONFIG_SHORTOPT_TOOLONG' ); }
handlers[key] = [type, isFlag]; }
for (let i = 0, len = argv.length; i < len; i++) { const wholeArg = argv[i];
if (stopAtPositional && result._.length > 0) { result._ = result._.concat(argv.slice(i)); break; }
if (wholeArg === '--') { result._ = result._.concat(argv.slice(i + 1)); break; }
if (wholeArg.length > 1 && wholeArg[0] === '-') { /* eslint-disable operator-linebreak */ const separatedArguments = wholeArg[1] === '-' || wholeArg.length === 2 ? [wholeArg] : wholeArg .slice(1) .split('') .map((a) => `-${a}`); /* eslint-enable operator-linebreak */
for (let j = 0; j < separatedArguments.length; j++) { const arg = separatedArguments[j]; const [originalArgName, argStr] = arg[1] === '-' ? arg.split(/=(.*)/, 2) : [arg, undefined];
let argName = originalArgName; while (argName in aliases) { argName = aliases[argName]; }
if (!(argName in handlers)) { if (permissive) { result._.push(arg); continue; } else { throw new ArgError( `unknown or unexpected option: ${originalArgName}`, 'ARG_UNKNOWN_OPTION' ); } }
const [type, isFlag] = handlers[argName];
if (!isFlag && j + 1 < separatedArguments.length) { throw new ArgError( `option requires argument (but was followed by another short argument): ${originalArgName}`, 'ARG_MISSING_REQUIRED_SHORTARG' ); }
if (isFlag) { result[argName] = type(true, argName, result[argName]); } else if (argStr === undefined) { if ( argv.length < i + 2 || (argv[i + 1].length > 1 && argv[i + 1][0] === '-' && !( argv[i + 1].match(/^-?\d*(\.(?=\d))?\d*$/) && (type === Number || // eslint-disable-next-line no-undef
(typeof BigInt !== 'undefined' && type === BigInt)) )) ) { const extended = originalArgName === argName ? '' : ` (alias for ${argName})`; throw new ArgError( `option requires argument: ${originalArgName}${extended}`, 'ARG_MISSING_REQUIRED_LONGARG' ); }
result[argName] = type(argv[i + 1], argName, result[argName]); ++i; } else { result[argName] = type(argStr, argName, result[argName]); } } } else { result._.push(wholeArg); } }
return result; }
arg.flag = (fn) => { fn[flagSymbol] = true; return fn; };
// Utility types
arg.COUNT = arg.flag((v, name, existingCount) => (existingCount || 0) + 1);
// Expose error class
arg.ArgError = ArgError;
module.exports = arg;
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