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