Add options to customize the notification message (#83)

index.js

@@ -106,13 +106,18 @@ UpdateNotifier.prototype.notify = function (opts) {
 
 	opts = opts || {};
 
-	var message = '\n' + boxen('Update available ' + chalk.dim(this.update.current) + chalk.reset(' → ') + chalk.green(this.update.latest) + ' \nRun ' + chalk.cyan('npm i -g ' + this.packageName) + ' to update', {
+	opts.message = opts.message || 'Update available ' + chalk.dim(this.update.current) + chalk.reset(' → ') +
+		chalk.green(this.update.latest) + ' \nRun ' + chalk.cyan('npm i -g ' + this.packageName) + ' to update';
+
+	opts.boxenOpts = opts.boxenOpts || {
 		padding: 1,
 		margin: 1,
 		align: 'center',
 		borderColor: 'yellow',
 		borderStyle: 'round'
-	});
+	};
+
+	var message = '\n' + boxen(opts.message, opts.boxenOpts);
 
 	if (opts.defer === undefined) {
 		process.on('exit', function () {

readme.md

@@ -118,6 +118,19 @@ Default: `true`
 
 Defer showing the notification to after the process has exited.
 
+#### options.message
+
+Type: `string`<br>
+Default: [See the screen shot above](https://github.com/yeoman/update-notifier#update-notifier-)
+
+The message that will be shown when an update is available.
+
+### options.boxenOpts
+
+Type: `object`<br>
+Default: `{ padding: 1, margin: 1, borderColor: 'yellow', borderStyle: 'round' }` ([See the screen shot above](https://github.com/yeoman/update-notifier#update-notifier-))
+
+The object that will be passed to [boxen](https://github.com/sindresorhus/boxen).
 
 ### User settings