noahmiller · May 15, 2014 16:54 · May 15, 2014
diff --git a/gulpfile-error-handling.js b/gulpfile-error-handling.js
@@ -0,0 +1,57 @@
+var gulp = require('gulp');
+var gutil = require('gulp-util');
+var jshint = require('gulp-jshint');
+
+// Command line option:
+//  --fatal=[warning|error|off]
+var fatalLevel = require('yargs').argv.fatal;
+
+var ERROR_LEVELS = ['error', 'warning'];
+
+// Return true if the given level is equal to or more severe than
+// the configured fatality error level.
+// If the fatalLevel is 'off', then this will always return false.
+// Defaults the fatalLevel to 'error'.
+function isFatal(level) {
+   return ERROR_LEVELS.indexOf(level) <= ERROR_LEVELS.indexOf(fatalLevel || 'error');
+}
+
+// Handle an error based on its severity level.
+// Log all levels, and exit the process for fatal levels.
+function handleError(level, error) {
+   gutil.log(error.message);
+   if (isFatal(level)) {
+      process.exit(1);
+   }
+}
+
+// Convenience handler for error-level errors.
+function onError(error) { handleError.call(this, 'error', error);}
+// Convenience handler for warning-level errors.
+function onWarning(error) { handleError.call(this, 'warning', error);}
+
+var testfiles = ['error.js', 'warning.js'];
+
+// Task that emits an error that's treated as a warning.
+gulp.task('warning', function() {
+   gulp.src(testfiles).
+      pipe(jshint()).
+      pipe(jshint.reporter('fail')).
+      on('error', onWarning);
+});
+
+// Task that emits an error that's treated as an error.
+gulp.task('error', function() {
+   gulp.src(testfiles).
+      pipe(jshint()).
+      pipe(jshint.reporter('fail')).
+      on('error', onError);
+});
+
+gulp.task('watch', function() {
+   // By default, errors during watch should not be fatal.
+   fatalLevel = fatalLevel || 'off';
+   gulp.watch(testfiles, ['error']);
+});
+
+gulp.task('default', ['watch']);