add hw2

node_modules/commander/lib/option.js

@@ -0,0 +1,380 @@
+const { InvalidArgumentError } = require('./error.js');
+
+class Option {
+  /**
+   * Initialize a new `Option` with the given `flags` and `description`.
+   *
+   * @param {string} flags
+   * @param {string} [description]
+   */
+
+  constructor(flags, description) {
+    this.flags = flags;
+    this.description = description || '';
+
+    this.required = flags.includes('<'); // A value must be supplied when the option is specified.
+    this.optional = flags.includes('['); // A value is optional when the option is specified.
+    // variadic test ignores <value,...> et al which might be used to describe custom splitting of single argument
+    this.variadic = /\w\.\.\.[>\]]$/.test(flags); // The option can take multiple values.
+    this.mandatory = false; // The option must have a value after parsing, which usually means it must be specified on command line.
+    const optionFlags = splitOptionFlags(flags);
+    this.short = optionFlags.shortFlag; // May be a short flag, undefined, or even a long flag (if option has two long flags).
+    this.long = optionFlags.longFlag;
+    this.negate = false;
+    if (this.long) {
+      this.negate = this.long.startsWith('--no-');
+    }
+    this.defaultValue = undefined;
+    this.defaultValueDescription = undefined;
+    this.presetArg = undefined;
+    this.envVar = undefined;
+    this.parseArg = undefined;
+    this.hidden = false;
+    this.argChoices = undefined;
+    this.conflictsWith = [];
+    this.implied = undefined;
+    this.helpGroupHeading = undefined; // soft initialised when option added to command
+  }
+
+  /**
+   * Set the default value, and optionally supply the description to be displayed in the help.
+   *
+   * @param {*} value
+   * @param {string} [description]
+   * @return {Option}
+   */
+
+  default(value, description) {
+    this.defaultValue = value;
+    this.defaultValueDescription = description;
+    return this;
+  }
+
+  /**
+   * Preset to use when option used without option-argument, especially optional but also boolean and negated.
+   * The custom processing (parseArg) is called.
+   *
+   * @example
+   * new Option('--color').default('GREYSCALE').preset('RGB');
+   * new Option('--donate [amount]').preset('20').argParser(parseFloat);
+   *
+   * @param {*} arg
+   * @return {Option}
+   */
+
+  preset(arg) {
+    this.presetArg = arg;
+    return this;
+  }
+
+  /**
+   * Add option name(s) that conflict with this option.
+   * An error will be displayed if conflicting options are found during parsing.
+   *
+   * @example
+   * new Option('--rgb').conflicts('cmyk');
+   * new Option('--js').conflicts(['ts', 'jsx']);
+   *
+   * @param {(string | string[])} names
+   * @return {Option}
+   */
+
+  conflicts(names) {
+    this.conflictsWith = this.conflictsWith.concat(names);
+    return this;
+  }
+
+  /**
+   * Specify implied option values for when this option is set and the implied options are not.
+   *
+   * The custom processing (parseArg) is not called on the implied values.
+   *
+   * @example
+   * program
+   *   .addOption(new Option('--log', 'write logging information to file'))
+   *   .addOption(new Option('--trace', 'log extra details').implies({ log: 'trace.txt' }));
+   *
+   * @param {object} impliedOptionValues
+   * @return {Option}
+   */
+  implies(impliedOptionValues) {
+    let newImplied = impliedOptionValues;
+    if (typeof impliedOptionValues === 'string') {
+      // string is not documented, but easy mistake and we can do what user probably intended.
+      newImplied = { [impliedOptionValues]: true };
+    }
+    this.implied = Object.assign(this.implied || {}, newImplied);
+    return this;
+  }
+
+  /**
+   * Set environment variable to check for option value.
+   *
+   * An environment variable is only used if when processed the current option value is
+   * undefined, or the source of the current value is 'default' or 'config' or 'env'.
+   *
+   * @param {string} name
+   * @return {Option}
+   */
+
+  env(name) {
+    this.envVar = name;
+    return this;
+  }
+
+  /**
+   * Set the custom handler for processing CLI option arguments into option values.
+   *
+   * @param {Function} [fn]
+   * @return {Option}
+   */
+
+  argParser(fn) {
+    this.parseArg = fn;
+    return this;
+  }
+
+  /**
+   * Whether the option is mandatory and must have a value after parsing.
+   *
+   * @param {boolean} [mandatory=true]
+   * @return {Option}
+   */
+
+  makeOptionMandatory(mandatory = true) {
+    this.mandatory = !!mandatory;
+    return this;
+  }
+
+  /**
+   * Hide option in help.
+   *
+   * @param {boolean} [hide=true]
+   * @return {Option}
+   */
+
+  hideHelp(hide = true) {
+    this.hidden = !!hide;
+    return this;
+  }
+
+  /**
+   * @package
+   */
+
+  _collectValue(value, previous) {
+    if (previous === this.defaultValue || !Array.isArray(previous)) {
+      return [value];
+    }
+
+    previous.push(value);
+    return previous;
+  }
+
+  /**
+   * Only allow option value to be one of choices.
+   *
+   * @param {string[]} values
+   * @return {Option}
+   */
+
+  choices(values) {
+    this.argChoices = values.slice();
+    this.parseArg = (arg, previous) => {
+      if (!this.argChoices.includes(arg)) {
+        throw new InvalidArgumentError(
+          `Allowed choices are ${this.argChoices.join(', ')}.`,
+        );
+      }
+      if (this.variadic) {
+        return this._collectValue(arg, previous);
+      }
+      return arg;
+    };
+    return this;
+  }
+
+  /**
+   * Return option name.
+   *
+   * @return {string}
+   */
+
+  name() {
+    if (this.long) {
+      return this.long.replace(/^--/, '');
+    }
+    return this.short.replace(/^-/, '');
+  }
+
+  /**
+   * Return option name, in a camelcase format that can be used
+   * as an object attribute key.
+   *
+   * @return {string}
+   */
+
+  attributeName() {
+    if (this.negate) {
+      return camelcase(this.name().replace(/^no-/, ''));
+    }
+    return camelcase(this.name());
+  }
+
+  /**
+   * Set the help group heading.
+   *
+   * @param {string} heading
+   * @return {Option}
+   */
+  helpGroup(heading) {
+    this.helpGroupHeading = heading;
+    return this;
+  }
+
+  /**
+   * Check if `arg` matches the short or long flag.
+   *
+   * @param {string} arg
+   * @return {boolean}
+   * @package
+   */
+
+  is(arg) {
+    return this.short === arg || this.long === arg;
+  }
+
+  /**
+   * Return whether a boolean option.
+   *
+   * Options are one of boolean, negated, required argument, or optional argument.
+   *
+   * @return {boolean}
+   * @package
+   */
+
+  isBoolean() {
+    return !this.required && !this.optional && !this.negate;
+  }
+}
+
+/**
+ * This class is to make it easier to work with dual options, without changing the existing
+ * implementation. We support separate dual options for separate positive and negative options,
+ * like `--build` and `--no-build`, which share a single option value. This works nicely for some
+ * use cases, but is tricky for others where we want separate behaviours despite
+ * the single shared option value.
+ */
+class DualOptions {
+  /**
+   * @param {Option[]} options
+   */
+  constructor(options) {
+    this.positiveOptions = new Map();
+    this.negativeOptions = new Map();
+    this.dualOptions = new Set();
+    options.forEach((option) => {
+      if (option.negate) {
+        this.negativeOptions.set(option.attributeName(), option);
+      } else {
+        this.positiveOptions.set(option.attributeName(), option);
+      }
+    });
+    this.negativeOptions.forEach((value, key) => {
+      if (this.positiveOptions.has(key)) {
+        this.dualOptions.add(key);
+      }
+    });
+  }
+
+  /**
+   * Did the value come from the option, and not from possible matching dual option?
+   *
+   * @param {*} value
+   * @param {Option} option
+   * @returns {boolean}
+   */
+  valueFromOption(value, option) {
+    const optionKey = option.attributeName();
+    if (!this.dualOptions.has(optionKey)) return true;
+
+    // Use the value to deduce if (probably) came from the option.
+    const preset = this.negativeOptions.get(optionKey).presetArg;
+    const negativeValue = preset !== undefined ? preset : false;
+    return option.negate === (negativeValue === value);
+  }
+}
+
+/**
+ * Convert string from kebab-case to camelCase.
+ *
+ * @param {string} str
+ * @return {string}
+ * @private
+ */
+
+function camelcase(str) {
+  return str.split('-').reduce((str, word) => {
+    return str + word[0].toUpperCase() + word.slice(1);
+  });
+}
+
+/**
+ * Split the short and long flag out of something like '-m,--mixed <value>'
+ *
+ * @private
+ */
+
+function splitOptionFlags(flags) {
+  let shortFlag;
+  let longFlag;
+  // short flag, single dash and single character
+  const shortFlagExp = /^-[^-]$/;
+  // long flag, double dash and at least one character
+  const longFlagExp = /^--[^-]/;
+
+  const flagParts = flags.split(/[ |,]+/).concat('guard');
+  // Normal is short and/or long.
+  if (shortFlagExp.test(flagParts[0])) shortFlag = flagParts.shift();
+  if (longFlagExp.test(flagParts[0])) longFlag = flagParts.shift();
+  // Long then short. Rarely used but fine.
+  if (!shortFlag && shortFlagExp.test(flagParts[0]))
+    shortFlag = flagParts.shift();
+  // Allow two long flags, like '--ws, --workspace'
+  // This is the supported way to have a shortish option flag.
+  if (!shortFlag && longFlagExp.test(flagParts[0])) {
+    shortFlag = longFlag;
+    longFlag = flagParts.shift();
+  }
+
+  // Check for unprocessed flag. Fail noisily rather than silently ignore.
+  if (flagParts[0].startsWith('-')) {
+    const unsupportedFlag = flagParts[0];
+    const baseError = `option creation failed due to '${unsupportedFlag}' in option flags '${flags}'`;
+    if (/^-[^-][^-]/.test(unsupportedFlag))
+      throw new Error(
+        `${baseError}
+- a short flag is a single dash and a single character
+  - either use a single dash and a single character (for a short flag)
+  - or use a double dash for a long option (and can have two, like '--ws, --workspace')`,
+      );
+    if (shortFlagExp.test(unsupportedFlag))
+      throw new Error(`${baseError}
+- too many short flags`);
+    if (longFlagExp.test(unsupportedFlag))
+      throw new Error(`${baseError}
+- too many long flags`);
+
+    throw new Error(`${baseError}
+- unrecognised flag format`);
+  }
+  if (shortFlag === undefined && longFlag === undefined)
+    throw new Error(
+      `option creation failed due to no flags found in '${flags}'.`,
+    );
+
+  return { shortFlag, longFlag };
+}
+
+exports.Option = Option;
+exports.DualOptions = DualOptions;