refactor: move help command to kernel itself

example/index.ts

@@ -7,7 +7,6 @@
 * file that was distributed with this source code.
 */
 
-// import { printHelpFor } from '../src/utils/help'
 import { BaseCommand } from '../src/BaseCommand'
 import { Kernel } from '../src/Kernel'
 import { args } from '../src/Decorators/args'
@@ -20,7 +19,7 @@ class Greet extends BaseCommand {
   @args.string({ description: 'The name of the person you want to greet' })
   public name: string
 
-  @args.number()
+  @args.string()
   public age: number
 
   @flags.string({ description: 'The environment to use to specialize certain commands' })
@@ -59,5 +58,4 @@ kernel.flag('env', (value) => {
 }, { type: 'string' })
 
 kernel.handle(process.argv.splice(2))
-
-// printHelpFor(Greet)
+kernel.printHelp(Greet)

index.ts

@@ -11,4 +11,3 @@ export { Kernel } from './src/Kernel'
 export { BaseCommand } from './src/BaseCommand'
 export { args } from './src/Decorators/args'
 export { flags } from './src/Decorators/flags'
-export { printHelp, printHelpFor } from './src/utils/help'

src/Contracts/index.ts

@@ -49,7 +49,7 @@ export type GlobalFlagHandler = (
  */
 export type CommandsGroup = {
   group: string,
-  commands: CommandConstructorContract[],
+  commands: HelpCommand[],
 }[]
 
 /**
@@ -84,3 +84,9 @@ export type ManifestCommand = Pick<
 export type ManifestNode = {
   [command: string]: ManifestCommand,
 }
+
+/**
+ * Shape of command required for the help screen. The node is a
+ * neutral point between `CommandConstructor` and `ManifestCommand`.
+ */
+export type HelpCommand = Pick<ManifestCommand, Exclude<keyof ManifestCommand, 'commandPath'>>

src/Kernel/index.ts

@@ -11,6 +11,7 @@ import * as getopts from 'getopts'
 
 import { Parser } from '../Parser'
 import { validateCommand } from '../utils/validateCommand'
+import { printHelp, printHelpFor } from '../utils/help'
 import { CommandConstructorContract, CommandFlag, GlobalFlagHandler } from '../Contracts'
 
 /**
@@ -185,4 +186,17 @@ export class Kernel {
 
     return this.runCommand(argv.splice(1), command)
   }
+
+  /**
+   * Print the help screen for a given command or all commands/flags
+   */
+  public printHelp (command?: CommandConstructorContract) {
+    if (command) {
+      printHelpFor(command)
+    } else {
+      const commands = Object.keys(this.commands).map((name) => this.commands[name])
+      const flags = Object.keys(this.flags).map((name) => this.flags[name])
+      printHelp(commands, flags)
+    }
+  }
 }

src/utils/help.ts

@@ -10,7 +10,7 @@
 import * as padRight from 'pad-right'
 import { green, bold, yellow, dim } from 'kleur'
 import { sortAndGroupCommands } from './sortAndGroupCommands'
-import { CommandConstructorContract, CommandArg, CommandFlag } from '../Contracts'
+import { CommandArg, CommandFlag, HelpCommand } from '../Contracts'
 
 /**
  * Wraps the command arg inside `<>` or `[]` brackets based upon if it's
@@ -53,7 +53,7 @@ function getArgsForDisplay (args: CommandArg[]) {
   })
 }
 
-function getCommandsForDisplay (commands: CommandConstructorContract[]) {
+function getCommandsForDisplay (commands: HelpCommand[]) {
   return commands.map(({ commandName, description }) => {
     return { displayName: commandName, description, width: commandName.length }
   })
@@ -63,7 +63,7 @@ function getCommandsForDisplay (commands: CommandConstructorContract[]) {
  * Prints help for all the commands by sorting them in alphabetical order
  * and grouping them as per their namespace.
  */
-export function printHelp (commands: CommandConstructorContract[], flags: CommandFlag[]): void {
+export function printHelp (commands: HelpCommand[], flags: CommandFlag[]): void {
   const flagsList = getFlagsForDisplay(flags)
   const commandsList = getCommandsForDisplay(commands)
 
@@ -103,7 +103,7 @@ export function printHelp (commands: CommandConstructorContract[], flags: Comman
 /**
  * Prints help for a single command
  */
-export function printHelpFor (command: CommandConstructorContract): void {
+export function printHelpFor (command: HelpCommand): void {
   if (command.description) {
     console.log('')
     console.log(command.description)

src/utils/sortAndGroupCommands.ts

@@ -7,14 +7,14 @@
 * file that was distributed with this source code.
 */
 
-import { CommandConstructorContract, CommandsGroup } from '../Contracts'
+import { CommandsGroup, HelpCommand } from '../Contracts'
 
  /**
  * Loops over the commands and converts them to an array of sorted groups with
  * nested commands inside them. The grouping is done using the command
  * namespace seperated with `:`. Example: `make:controller`
  */
-export function sortAndGroupCommands (commands: CommandConstructorContract[]): CommandsGroup {
+export function sortAndGroupCommands (commands: HelpCommand[]): CommandsGroup {
   /**
    * Create a group of commands using it's namespace
    */
@@ -31,7 +31,7 @@ export function sortAndGroupCommands (commands: CommandConstructorContract[]): C
     result[group].push(command)
 
     return result
-  }, {} as { [key: string]: CommandConstructorContract[] })
+  }, {} as { [key: string]: HelpCommand[] })
 
   /**
    * Convert the object literal groups and it's command to an