Flag Inheritance

There are some instances where you might want to define a flag once for all of your commands. In this case you can add a base flag to an abstract base Command class. For example,

import { Command, Flags } from '@oclif/core';

export abstract class BaseCommand extends Command {
  static baseFlags = {
    interactive: Flags.boolean({
      char: 'i',
      description: 'Run command in interactive mode',
      // Show this flag under a separate GLOBAL section in help.
      helpGroup: 'GLOBAL',
    }),
  };
}

Any command that extends BaseCommand will now have an --interactive flag on it.

If you are going to stack multiple layers of abstract Command classes, then you must spread the baseFlags to ensure that the flags are properly inherited. For example,

import { Command, Flags } from '@oclif/core';

export abstract class FirstBaseCommand extends Command {
  static baseFlags = {
    interactive: Flags.boolean({
      char: 'i',
      description: 'Run command in interactive mode',
      // Show this flag under a separate GLOBAL section in help.
      helpGroup: 'GLOBAL',
    }),
  };
}

export abstract class SecondBaseCommand extends FirstBaseCommand {
  static baseFlags = {
    ...FirstBaseCommand.baseFlags,
    'log-level': Flags.option({
      default: 'info',
      description: 'Specify log level',
      helpGroup: 'GLOBAL',
      options: ['debug', 'warn', 'error', 'info', 'trace'] as const,
      summary: 'Specify level for logging.',
      char: 'l',
    })(),
  };
}

export abstract class ThirdBaseCommand extends SecondBaseCommand {
  static baseFlags = {
    ...SecondBaseCommand.baseFlags,
    verbose: Flags.boolean({
      description: 'Show verbose output.',
      char: 'v'
    })
  };
}