Add new API method for failing build upon validation error

index.js

@@ -3,6 +3,8 @@ var gutil = require('gulp-util'),
   PJV = require('package-json-validator').PJV,
   through = require('through2');
 
+var PLUGIN_NAME = require('./package').name;
+
 function printErrors(results) {
   if (results) {
 
@@ -41,11 +43,11 @@ function printErrors(results) {
     }
 
   } else {
-    throw new gutil.PluginError('gulp-nice-package', 'Failed to get results from validator');
+    throw new gutil.PluginError(PLUGIN_NAME, 'Failed to get results from validator');
   }
 }
 
-module.exports = function (spec, options) {
+var nicePackagePlugin = function (spec, options) {
 
   function validate(file, enc, cb) {
 
@@ -55,7 +57,7 @@ module.exports = function (spec, options) {
     }
 
     if (file.isStream()) {
-      this.emit('error', new gutil.PluginError('gulp-nice-package', 'Streaming not supported'));
+      this.emit('error', new gutil.PluginError(PLUGIN_NAME, 'Streaming not supported'));
       return cb();
     }
 
@@ -70,4 +72,28 @@ module.exports = function (spec, options) {
   }
 
   return through.obj(validate);
-};
+};
+
+nicePackagePlugin.failOnError = function () {
+  return through.obj(function (file, enc, cb) {
+    var error = null;
+
+    function size(arr) {
+      return arr ? arr.length : 0;
+    }
+
+    if (file.nicePackage.valid === false) {
+      error = new gutil.PluginError(
+        PLUGIN_NAME,
+        'Failed with ' +
+            size(file.nicePackage.errors) + ' error(s), ' +
+            size(file.nicePackage.warnings) + ' warning(s), ' +
+            size(file.nicePackage.recommendations) + ' recommendation(s)'
+      );
+    }
+
+    return cb(error, file);
+  });
+};
+
+module.exports = nicePackagePlugin;

readme.md

@@ -78,6 +78,21 @@ I know, it seems a bit terse. The reasoning is, you may want to pipe other trans
 error is thrown, the pipe will cease and you have no way to continue. A valid use case may be to actually fix the
 the package.json file programmatically if it's invalid, e.g. with [gulp-shrinkwrap](https://github.com/chmontgomery/gulp-shrinkwrap).
 
+If you have no need to further process the stream after validation, you can pipe the stream to `validate.failOnError()`
+to fail the build in the event one or more errors are raised during validation.
+
+```js
+// gulpfile.js
+var gulp = require('gulp');
+var validate = require('gulp-nice-package');
+
+gulp.task('validate-json', function () {
+  return gulp.src('package.json')
+    .pipe(validate())
+    .pipe(validate.failOnError());
+});
+```
+
 ## License
 
 [MIT](http://opensource.org/licenses/MIT) © [Chris Montgomery](http://www.chrismontgomery.info/)

test/validation.js

@@ -3,6 +3,20 @@ var gutil = require('gulp-util'),
   validator = require('./../index.js'),
   assert = require('assert');
 
+function createPackageFile(path) {
+  return new gutil.File({
+    contents: new Buffer(JSON.stringify(require(path)))
+  });
+}
+
+function createInvalidPackageFile() {
+  return createPackageFile('./fixtures/package-with-errors.json');
+}
+
+function createValidPackageFile() {
+  return createPackageFile('./fixtures/package-valid.json');
+}
+
 it('should have invalid json file', function (cb) {
   var stream = validator();
 
@@ -12,9 +26,7 @@ it('should have invalid json file', function (cb) {
     cb();
   });
 
-  stream.write(new gutil.File({
-    contents: new Buffer(JSON.stringify(require('./fixtures/package-with-errors.json')))
-  }));
+  stream.write(createInvalidPackageFile());
 });
 
 it('should have valid json file', function (cb) {
@@ -25,7 +37,44 @@ it('should have valid json file', function (cb) {
     cb();
   });
 
-  stream.write(new gutil.File({
-    contents: new Buffer(JSON.stringify(require('./fixtures/package-valid.json')))
-  }));
+  stream.write(createValidPackageFile());
+});
+
+describe('failOnError', function () {
+  it('should report an error when the json file is invalid', function (cb) {
+    var errorReported = false;
+    var stream = validator()
+      .on('end', function () {
+        assert.ok(errorReported);
+        cb();
+      });
+
+    stream
+      .pipe(validator.failOnError())
+      .on('error', function (error) {
+        errorReported = true;
+        assert.strictEqual(error.message, 'Failed with 1 error(s), 3 warning(s), 2 recommendation(s)');
+      });
+
+    stream.write(createInvalidPackageFile());
+    stream.end();
+  });
+
+  it('should not report an error when the json file is valid', function (cb) {
+    var errorReported = false;
+    var stream = validator()
+      .on('end', function () {
+        assert.ok(!errorReported);
+        cb();
+      });
+
+    stream
+      .pipe(validator.failOnError())
+      .on('error', function () {
+        errorReported = true;
+      });
+
+    stream.write(createValidPackageFile());
+    stream.end();
+  });
 });