196 lines
4.4 KiB
JavaScript
196 lines
4.4 KiB
JavaScript
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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