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const flagSymbol = Symbol('arg flag'); | |
function arg(opts, {argv = process.argv.slice(2), permissive = false, stopAtPositional = false} = {}) { | |
if (!opts) { | |
throw new Error('Argument specification object is required'); | |
} | |
const result = {_: []}; | |
const aliases = {}; | |
const handlers = {}; | |
for (const key of Object.keys(opts)) { | |
if (!key) { | |
throw new TypeError('Argument key cannot be an empty string'); | |
} | |
if (key[0] !== '-') { | |
throw new TypeError(`Argument key must start with '-' but found: '${key}'`); | |
} | |
if (key.length === 1) { | |
throw new TypeError(`Argument key must have a name; singular '-' keys are not allowed: ${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 TypeError(`Type missing or not a function or valid array type: ${key}`); | |
} | |
if (key[1] !== '-' && key.length > 2) { | |
throw new TypeError(`Short argument keys (with a single hyphen) must have only one character: ${key}`); | |
} | |
handlers[key] = [type, isFlag]; | |
} | |
for (let i = 0, len = argv.length; i < len; i++) { | |
const wholeArg = argv[i]; | |
if (stopAtPositional && result._.length > 0) { | |
result._ = result._.concat(argv.slice(i)); | |
break; | |
} | |
if (wholeArg === '--') { | |
result._ = result._.concat(argv.slice(i + 1)); | |
break; | |
} | |
if (wholeArg.length > 1 && wholeArg[0] === '-') { | |
/* eslint-disable operator-linebreak */ | |
const separatedArguments = (wholeArg[1] === '-' || wholeArg.length === 2) | |
? [wholeArg] | |
: wholeArg.slice(1).split('').map(a => `-${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 { | |
const err = new Error(`Unknown or unexpected option: ${originalArgName}`); | |
err.code = 'ARG_UNKNOWN_OPTION'; | |
throw err; | |
} | |
} | |
const [type, isFlag] = handlers[argName]; | |
if (!isFlag && ((j + 1) < separatedArguments.length)) { | |
throw new TypeError(`Option requires argument (but was followed by another short argument): ${originalArgName}`); | |
} | |
if (isFlag) { | |
result[argName] = type(true, argName, result[argName]); | |
} else if (argStr === undefined) { | |
if ( | |
argv.length < i + 2 || | |
( | |
argv[i + 1].length > 1 && | |
(argv[i + 1][0] === '-') && | |
!( | |
argv[i + 1].match(/^-?\d*(\.(?=\d))?\d*$/) && | |
( | |
type === Number || | |
// eslint-disable-next-line no-undef | |
(typeof BigInt !== 'undefined' && type === BigInt) | |
) | |
) | |
) | |
) { | |
const extended = originalArgName === argName ? '' : ` (alias for ${argName})`; | |
throw new Error(`Option requires argument: ${originalArgName}${extended}`); | |
} | |
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); | |
module.exports = arg; | |