Method outputHelp

lib/command.js:2519–2558

* Output help information for this command. * * Outputs built-in help, and custom text added using `.addHelpText()`. * * @param {{ error: boolean } | Function} [contextOptions] - pass {error:true} to write to stderr instead of stdout

(contextOptions)

   */

  outputHelp(contextOptions) {
    let deprecatedCallback;
    if (typeof contextOptions === 'function') {
      deprecatedCallback = contextOptions;
      contextOptions = undefined;
    }

    const outputContext = this._getOutputContext(contextOptions);
    /** @type {HelpTextEventContext} */
    const eventContext = {
      error: outputContext.error,
      write: outputContext.write,
      command: this,
    };

    this._getCommandAndAncestors()
      .reverse()
      .forEach((command) => command.emit('beforeAllHelp', eventContext));
    this.emit('beforeHelp', eventContext);

    let helpInformation = this.helpInformation({ error: outputContext.error });
    if (deprecatedCallback) {
      helpInformation = deprecatedCallback(helpInformation);
      if (
        typeof helpInformation !== 'string' &&
        !Buffer.isBuffer(helpInformation)
      ) {
        throw new Error('outputHelp callback must return a string or a Buffer');
      }
    }
    outputContext.write(helpInformation);

    if (this._getHelpOption()?.long) {
      this.emit(this._getHelpOption().long); // deprecated
    }
    this.emit('afterHelp', eventContext);
    this._getCommandAndAncestors().forEach((command) =>
      command.emit('afterAllHelp', eventContext),
    );
  }

  /**
   * You can pass in flags and a description to customise the built-in help option.