Resolve "Add zsh, fish, and bash shell completion helper function generation as well as the related command"

Closes #4 (closed)

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

-import { existsSync, writeFileSync } from 'fs';
-import inquirer from 'inquirer';
-import CommanderCommand from '../../CommanderCommand';
+import { existsSync, writeFileSync }       from 'fs';
+import inquirer                            from 'inquirer';
+import CommanderCommand                    from '../../CommanderCommand';
 import { generateBashCompletion, getRoot } from '../../../helpers/AutoCompletionHelper';
 
+
 class CompletionBashCommand extends CommanderCommand {
     protected commandName: string = 'bash';
 
-    protected default_filename: string = './dojo_bash_completion.sh'
+    protected defaultFilename: string = './dojo_bash_completion.sh';
 
     writeFile(filename: string) {
         const installInstructions: string = `
@@ -16,43 +17,43 @@ overwrite it, if it only contains the 'dojo' completion.
 
 This can be performed by either
 
-cat ${filename} > ~/.bash_completion  # overwrites .bash_completion
-cat ${filename} >> ~/.bash_completion # appends to .bash_completion
+cat ${ filename } > ~/.bash_completion  # overwrites .bash_completion
+cat ${ filename } >> ~/.bash_completion # appends to .bash_completion
 
 For more details: <https://github.com/scop/bash-completion/blob/master/README.md>
-`
+`;
         try {
-            writeFileSync(filename, generateBashCompletion(getRoot(this.command)))
-            console.log(`Bash completion successfully written.`)
-            console.log(`${installInstructions}`)
-        } catch (error) {
-            console.log(`Error: ${error}.`)
+            writeFileSync(filename, generateBashCompletion(getRoot(this.command)));
+            console.log(`Bash completion successfully written.`);
+            console.log(`${ installInstructions }`);
+        } catch ( error ) {
+            console.log(`Error: ${ error }.`);
         }
     }
 
     protected defineCommand() {
         this.command
-            .description('generate bash completion')
-            .option(`-f, --file <filename>', 'complete path of the filename where the bash completion will be stored (default to ${this.default_filename}).`)
-            .action(this.commandAction.bind(this));
+        .description('generate bash completion')
+        .option('-f, --file <filename>', `complete path of the filename where the bash completion will be stored (default to ${ this.defaultFilename }).`, this.defaultFilename)
+        .option('-y, --force', 'don\'t ask for file overwrite confirmation')
+        .action(this.commandAction.bind(this));
     }
 
-    protected async commandAction(options: { file?: string }): Promise<void> {
-        const filename = options.file ?? this.default_filename
-        if (existsSync(filename)) {
+    protected async commandAction(options: { file: string, force: boolean }): Promise<void> {
+        if ( !options.force && existsSync(options.file) ) {
             // File exists in path
             const confirm: boolean = (await inquirer.prompt({
-                name: 'confirm',
-                message: `${options.file} is going to be overwritten. Are you sure?`,
-                type: 'confirm',
-                default: false
-            })).confirm;
-
-            if (confirm) {
-                this.writeFile(filename)
+                                                                name   : 'confirm',
+                                                                message: `${ options.file } is going to be overwritten. Are you sure?`,
+                                                                type   : 'confirm',
+                                                                default: false
+                                                            })).confirm;
+
+            if ( confirm ) {
+                this.writeFile(options.file);
             }
         } else {
-            this.writeFile(filename)
+            this.writeFile(options.file);
         }
     }
 }