Completion command => Add get command based on current input for zsh and bash

NodeApp/src/commander/completion/subcommands/CompletionGetCommand.ts

+import CommanderCommand                    from '../../CommanderCommand';
+import { Command, CommandOptions, Option } from 'commander';
+import * as AutoCompletionHelper           from '../../../helpers/AutoCompletionHelper';
+
+
+type CompletionProposal = { name: string, description: string };
+
+
+class CompletionGetCommand extends CommanderCommand {
+    protected commandName: string = 'get';
+    protected options: CommandOptions = {
+        hidden: true
+    };
+
+    protected defineCommand() {
+        this.command.description('generate completion options for a given command')
+            .addOption(new Option('-s, --shell <shell>', 'shell completion result format').choices([ 'bash', 'zsh' ]))
+            .argument('<commands...>', 'command chain to complete')
+            .action(this.commandAction.bind(this));
+    }
+
+    private completion(commandsChain: Array<string>, displayFunction: (completionProposals: Array<CompletionProposal>) => void) {
+        const command = AutoCompletionHelper.getCommandFromChain(AutoCompletionHelper.getRoot(this.command), commandsChain.slice(1));
+
+        if ( command ) {
+            const commands = command.commands.filter(cmd => !(cmd as Command & { _hidden: boolean })._hidden);
+            const options = command.options.filter(option => !option.hidden);
+
+            displayFunction([ ...commands.flatMap(cmd => [ {
+                name       : cmd.name(),
+                description: cmd.description()
+            }, ...cmd.aliases().map(alias => ({
+                name       : alias,
+                description: cmd.description()
+            })) ]), ...options.flatMap(option => [ {
+                name       : option.long,
+                description: option.description
+            }, {
+                name       : option.short,
+                description: option.description
+            } ]) ].filter(proposal => proposal.name) as Array<CompletionProposal>);
+        }
+    }
+
+    private bashCompletion(commandsChain: Array<string>) {
+        this.completion(commandsChain, (completionProposals: Array<CompletionProposal>) => console.log(completionProposals.map(proposal => proposal.name).join(' ')));
+    }
+
+    private zshCompletion(commandsChain: Array<string>) {
+        this.completion(commandsChain, (completionProposals: Array<CompletionProposal>) => completionProposals.forEach(proposal => console.log(`${ proposal.name }:${ proposal.description }`)));
+    }
+
+    protected async commandAction(commandsChain: Array<string>, options: { shell: 'bash' | 'zsh' }): Promise<void> {
+        switch ( options.shell ) {
+            case 'bash':
+                this.bashCompletion(commandsChain);
+                break;
+            case 'zsh':
+                this.zshCompletion(commandsChain);
+                break;
+            default:
+                console.error('Unsupported shell completion format');
+                break;
+        }
+    }
+}
+
+
+export default new CompletionGetCommand();
\ No newline at end of file