Command

Introduced in 4.0.0

Stability: 2 - Stable

The Command library provides a set of methods for building and executing a basic CLI utility. Which can be ran programatically through the parse() method.

const { Command } = require('kado')

Class Command

This class is a super class that is extended by the command section within the Application core object. Let us take a look at that usage snippet.

const CommandSuper = require('./Command')
class Command extends CommandSuper {
  constructor () {
    super()
    this.name = name
    this.options = options
    this.version = that.version
  }
  action (opts) {
    return options.action.call(this,opts)
  }
}
this.commands[module][name] = new Command()

When the child Command class is setup it presets the options and version which could be defined in a number of ways.

• options {object} containing command flags and other options
• version {string} Semver style string to denote version eg 1.0.0

Now take a look at an actual options object.

const options = {
  description: 'Some command description',
  options: [
    { definition: '-s, --something <s>', description: 'Some thing' }
  ],
  action: (opts) => {
    return Promise.resolve(opts)
  }
}

• description is used to print the help.
• options contains the actual flags.
• {definition: 'cli flags', description: 'flag description'} used to print help and parse entries.
• action {Function} taking opts being parsed CLI arguments and their values and returning an optional {Promise} that resolves when the command action is complete.

Command.constructor()

• Return {Command} Construct a new instance of the Command library.

Command.checkLog()

• Return {undefined}

Throws an error when the logger has not been defined.

Command.checkOptions()

• Return {undefined}

Throws an error when the options have not been defined.

Command.checkParser()

• Return {undefined}

Throws an error when the parser has not been defined.

Command.printVersion()

• Return {undefined}

Prints the current version of the program through the log.info() method.

Command.generateHelp()

• Return {string} ready to print help menu

Command.printHelp()

• Return {undefined}

Uses console.log() to display the output of generateHelp()

Command.action()

• Return {undefined}

Skeleton function meant to be overridden by the actual command and will throw an error if it still exists.

Command.parse(argv)

• argv {Array} command line arguments one per array entry
• Return {Promise} the promise will complete when the action() call completes.

Class: CommandServer

CommandServer provides a run time for executing command line style commands either via API or actual TTY. This makes testing and programmable usage trivial.

static CommandServer.getInstance()

• Return {CommandServer} new instance of the server

CommandServer.constructor()

• Return {CommandServer} new instance of the server

CommandServer.setVersion(version)

• version {string} set the version of the server.
• Return {string} the version passed

CommandServer.addCommand(module, name, command)

• module {string} name of the module
• name {string} name of the command
• command {Command} instance of Command to be used.
• Return {string} name of the command added.

CommandServer.getCommand(module, name)

• module {string} name of the module
• name {string} name of the command
• Return {object} when command is found Throws an Error when no command or module are found.

CommandServer.removeCommand(module, name)

• module {string} name of the module
• name {string} name of the command Return {string} name of the command requested for removal.

CommandServer.all()

• Return {object} list of registered commands.

CommandServer.command(module, name, options)

• module {string} name of the module
• name {string} name of the command
• options {object} description, flags and action for the command
• Return {string} name of the command added.

This actually uses the Command library to setup the new command based on the options and is a shortcut for.

CommandServer.addCommand('someModule','someCommand',new Command())

CommandServer.run(command)

• command {string|array} String containing command or Array of argv.
• Return {Promise} that will be resolved when the action command completes.