438     const option = new Option(flags, description);
439     const oname = option.name();
440     const name = option.attributeName();
441     option.mandatory = !!config.mandatory;
460     if (option.negate || option.optional || option.required || typeof defaultValue === 'boolean') {
462       if (option.negate) {
463         const positiveLongFlag = option.long.replace(/^--no-/, '--');
469         option.defaultValue = defaultValue;
474     this.options.push(option);
488           this._setOptionValue(name, option.negate
496         this._setOptionValue(name, option.negate ? false : val);
555   option(flags, description, fn, defaultValue) {  method in Command
952     return this.options.find(option => option.is(arg));
1012         const option = this._findOption(arg);
1014         if (option) {
1015           if (option.required) {
1017             if (value === undefined) this.optionMissingArgument(option);
1018             this.emit(`option:${option.name()}`, value);
1019           } else if (option.optional) {
1025             this.emit(`option:${option.name()}`, value);
1027             this.emit(`option:${option.name()}`);
1035         const option = this._findOption(`-${arg[1]}`);
1036         if (option) {
1037           if (option.required || option.optional) {
1039             this.emit(`option:${option.name()}`, arg.slice(2));
1042             this.emit(`option:${option.name()}`);
1052         const option = this._findOption(arg.slice(0, index));
1053         if (option && (option.required || option.optional)) {
1054           this.emit(`option:${option.name()}`, arg.slice(index + 1));
1114   optionMissingArgument(option, flag) {  argument
1117       message = `error: option '${option.flags}' argument missing, got '${flag}'`;
1119       message = `error: option '${option.flags}' argument missing`;
1132   missingMandatoryOptionValue(option) {  argument
1133     const message = `error: required option '${option.flags}' not specified`;
1353     return options.reduce((max, option) => {
1354       return Math.max(max, option.flags.length);
1411     const help = this.options.map((option) => {
1412       const fullDesc = option.description +
1413 …((!option.negate && option.defaultValue !== undefined) ? ' (default: ' + JSON.stringify(option.def…
1414       return padOptionDetails(option.flags, fullDesc);