Fixes #26; For interfaces that need to have either a non-zero exit co…

…de, or some other way to determine if things should halt, this flag will allow the caller to have any errors reported as a failure of the process.

README.md

@@ -159,6 +159,33 @@ If you pass `--no-color` it will overwrite the default and give you plain text.
 
 If you pass `-v`, it will give you the lines in each file, as well as a merged version (useful for copy/pasting to update the metadata).
 
+`--fail-on-errors` If this is passed, and *any* files report errors, this will send a non-zero exit code. This is useful if you're using it from the command line, and wish to halt the execution of any other actions.
+If you are using the Node API instead of the CLI, then the results array returned from the Promise will have a property of `EXIT_WITH_FAILURE` set to true.
+Examples of how you might use this (though, probably not often, at least until I have time to distinguish errors from warnings).
+
+**CLI**
+```
+csf some_file_with_errors.css --fail-on-errors && do_some_new_build_task
+```
+**Node API**
+```javascript
+var cliInstance = new cli.CLI(
+	{
+		args: ['some_file_with_errors.js'],
+		flags: {
+			failOnErrors: true
+		}
+	}
+);
+
+cliInstance.init().then(
+	function(results) {
+		console.log(results.EXIT_WITH_FAILURE); // logs out 'true'
+	}
+);
+```
+
+
 ## Sublime Text Integration
 There are now two ways you can integrate this module with Sublime Text:
 

bin/index.js

@@ -22,7 +22,7 @@ var config = new ConfigStore(
 );
 
 var cli = require('../lib/cli').init().then(
-	function() {
+	function(results) {
 		var deprecated = deprecationCheck(
 			{
 				config,
@@ -34,5 +34,9 @@ var cli = require('../lib/cli').init().then(
 		if (deprecated) {
 			console.log(deprecated);
 		}
+
+		if (results.EXIT_WITH_FAILURE === true) {
+			process.exitCode = 1;
+		}
 	}
 );

lib/argv.js

@@ -24,6 +24,10 @@ var optimist = require('optimist')
 			boolean: true,
 			default: false
 		},
+		'fail-on-errors': {
+			boolean: true,
+			default: false
+		},
 		i: {
 			alias: 'inline-edit',
 			boolean: true,

lib/cli.js

@@ -212,6 +212,10 @@ class CLI extends EventEmitter {
 			this.openFiles(results);
 		}
 
+		if (this.flags.failOnErrors && this._logger.testStats.failures) {
+			results.EXIT_WITH_FAILURE = true;
+		}
+
 		return results;
 	}
 

test/cli.js

@@ -670,6 +670,32 @@ describe(
 			}
 		);
 
+		it(
+			'should indicate if the process should should fail on stdout',
+			function() {
+				sandbox.stub(fs, 'readFile').callsFake(invalidContentStub);
+
+				var logger = new Logger.constructor();
+
+				var cliInstance = new cli.CLI(
+					{
+						args: ['foo.js'],
+						flags: {
+							failOnErrors: true
+						},
+						log: _.noop,
+						logger: logger
+					}
+				);
+
+				return cliInstance.init().then(
+					function(results) {
+						assert.isTrue(results.EXIT_WITH_FAILURE, 'files that output errors should have a non-zero exitCode when --fail-on-errors is passed');
+					}
+				);
+			}
+		);
+
 		it(
 			'should handle custom config',
 			function() {