fix(errors): emit errors of type GulpUglifyError

Use a lightweight wrapper to construct custom Error subtypes to replace
`PluginError`. Original errors from UglifyJS are now preserved, and
available as the "cause" property.

BREAKING CHANGE: Emitted errors are of a new type. Original UglifyJS
error message are preserved instead of the attempt to normalize them.
The constructor is exported as "GulpUglifyError" to allow for instance
checks.

README.md

@@ -89,11 +89,17 @@ UglifyJS's behavior.
 ## Errors
 
 `gulp-uglify` emits an 'error' event if it is unable to minify a specific file.
-Wherever possible, the PluginError object will contain the following properties:
+The GulpUglifyError constructor is exported by this plugin for `instanceof` checks.
+It contains the following properties:
 
-- `fileName`
-- `lineNumber`
-- `message`
+- `fileName`: The full file path for the file being minified.
+- `cause`: The original UglifyJS error, if avialable.
+
+Most UglifyJS error messages have the following properties:
+
+- `message` (or `msg`)
+- `filename`
+- `line`
 
 ## Using a Different UglifyJS
 

index.js

@@ -1,7 +1,10 @@
 'use strict';
 var uglify = require('uglify-js');
 var minifier = require('./minifier');
+var GulpUglifyError = require('./lib/gulp-uglify-error');
 
 module.exports = function (opts) {
   return minifier(opts, uglify);
 };
+
+module.exports.GulpUglifyError = GulpUglifyError;

lib/create-error.js

@@ -1,22 +1,13 @@
 'use strict';
-var PluginError = require('gulp-util/lib/PluginError');
-
-var pluginName = 'gulp-uglify';
-
-module.exports = function createError(file, err) {
-  if (typeof err === 'string') {
-    return new PluginError(pluginName, file.path + ': ' + err, {
-      fileName: file.path,
-      showStack: false
-    });
-  }
-
-  var msg = err.message || err.msg || 'unspecified error';
-
-  return new PluginError(pluginName, file.path + ': ' + msg, {
-    fileName: file.path,
-    lineNumber: err.line,
-    stack: err.stack,
-    showStack: false
-  });
-};
+var curry = require('lodash/fp/curry');
+var GulpUglifyError = require('./gulp-uglify-error');
+
+function createError(file, msg, cause) {
+  var perr = new GulpUglifyError(msg, cause);
+  perr.plugin = 'gulp-uglify';
+  perr.fileName = file.path;
+  perr.showStack = false;
+  return perr;
+}
+
+module.exports = curry(createError);

lib/gulp-uglify-error.js

@@ -0,0 +1,4 @@
+'use strict';
+var makeErrorCause = require('make-error-cause');
+
+module.exports = makeErrorCause('GulpUglifyError');

minifier.js

@@ -1,6 +1,5 @@
 'use strict';
 var through = require('through2');
-var PluginError = require('gulp-util/lib/PluginError');
 var applySourceMap = require('vinyl-sourcemaps-apply');
 var saveLicense = require('uglify-save-license');
 var isObject = require('lodash/fp/isObject');
@@ -11,6 +10,7 @@ var _ = require('lodash/fp/placeholder');
 var defaultsDeep = require('lodash/fp/defaultsDeep');
 var log = require('./lib/log');
 var createError = require('./lib/create-error');
+var GulpUglifyError = require('./lib/gulp-uglify-error');
 
 var reSourceMapComment = /\n\/\/# sourceMappingURL=.+?$/;
 
@@ -59,7 +59,7 @@ module.exports = function (opts, uglify) {
     }
 
     if (file.isStream()) {
-      return callback(createError(file, 'Streaming not supported'));
+      return callback(createError(file, 'Streaming not supported', null));
     }
 
     if (file.sourceMap) {
@@ -79,9 +79,9 @@ module.exports = function (opts, uglify) {
       var m = uglify.minify(map, options);
       m.code = new Buffer(m.code.replace(reSourceMapComment, ''));
       return m;
-    }, createError.bind(null, file));
+    }, createError(file, 'unable to minify JavaScript'));
 
-    if (mangled instanceof PluginError) {
+    if (mangled instanceof GulpUglifyError) {
       return callback(mangled);
     }
 

package.json

@@ -5,10 +5,10 @@
   "author": "Terin Stock <[email protected]>",
   "bugs": "https://github.com/terinjokes/gulp-uglify/issues",
   "dependencies": {
-    "gulp-util": "^3.0.0",
     "gulplog": "^1.0.0",
     "has-gulplog": "^0.1.0",
     "lodash": "^4.13.1",
+    "make-error-cause": "^1.1.1",
     "through2": "^2.0.0",
     "uglify-js": "2.7.0",
     "uglify-save-license": "^0.4.1",

test/create-error.js

@@ -2,6 +2,7 @@
 var test = require('tape');
 var Vinyl = require('vinyl');
 var createError = require('../lib/create-error');
+var GulpUglifyError = require('../lib/gulp-uglify-error');
 
 var testOkContentsInput = '"use strict"; (function(console, first, second) { console.log(first + second) }(5, 10))';
 var testFile = new Vinyl({
@@ -11,11 +12,25 @@ var testFile = new Vinyl({
   contents: new Buffer(testOkContentsInput)
 });
 
-test('should report "unspecified error" if err has no msg or message properties', function (t) {
-  t.plan(3);
-  var e = createError(testFile, {});
+test('should have expected error message', function (t) {
+  t.plan(5);
+  var e = createError(testFile, 'error message text', null);
 
-  t.ok(e instanceof Error, 'argument should be of type error');
+  t.ok(e instanceof Error, 'argument should be of type Error');
+  t.ok(e instanceof GulpUglifyError, 'argument should be of type GulpUglifyError');
   t.equal(e.plugin, 'gulp-uglify', 'error is from gulp-uglify');
-  t.true(e.message.match(/unspecified error$/), 'error should not be specified');
+  t.equal(e.message, 'error message text');
+  t.notOk(e.cause, 'should not contain a cause');
+});
+
+test('should wrap cause', function (t) {
+  t.plan(5);
+  var cause = new Error('boom!');
+  var e = createError(testFile, 'error message text', cause);
+
+  t.ok(e instanceof Error, 'argument should be of type Error');
+  t.ok(e instanceof GulpUglifyError, 'argument should be of type GulpUglifyError');
+  t.equal(e.plugin, 'gulp-uglify', 'error is from gulp-uglify');
+  t.ok(e.message.match(/^error message text/));
+  t.equal(e.cause, cause);
 });

test/err.js

@@ -1,6 +1,7 @@
 'use strict';
 var test = require('tape');
 var Vinyl = require('vinyl');
+var GulpUglifyError = require('../lib/gulp-uglify-error');
 var gulpUglify = require('../');
 
 var testContentsInput = 'function errorFunction(error)\n{';
@@ -21,7 +22,7 @@ var testFile2 = new Vinyl({
 });
 
 test('should report files in error', function (t) {
-  t.plan(6);
+  t.plan(7);
 
   var stream = gulpUglify();
 
@@ -30,10 +31,11 @@ test('should report files in error', function (t) {
   });
 
   stream.on('error', function (e) {
-    t.ok(e instanceof Error, 'argument should be of type error');
+    t.ok(e instanceof Error, 'argument should be of type Error');
+    t.ok(e instanceof GulpUglifyError, 'argument should be of type GulpUglifyError');
     t.equal(e.plugin, 'gulp-uglify', 'error is from gulp-uglify');
     t.equal(e.fileName, testFile1.path, 'error reports correct file name');
-    t.equal(e.lineNumber, 2, 'error reports correct line number');
+    t.equal(e.cause.line, 2, 'error reports correct line number');
     t.ok(e.stack, 'error has a stack');
     t.false(e.showStack, 'error is configured to not print the stack');
   });
@@ -43,7 +45,7 @@ test('should report files in error', function (t) {
 });
 
 test('shouldn\'t blow up when given output options', function (t) {
-  t.plan(5);
+  t.plan(6);
 
   var stream = gulpUglify({
     output: {
@@ -56,8 +58,9 @@ test('shouldn\'t blow up when given output options', function (t) {
   });
 
   stream.on('error', function (e) {
-    t.ok(e instanceof Error, 'argument should be of type error');
-    t.equals(e.message, testFile2.path + ': `exportAll` is not a supported option');
+    t.ok(e instanceof Error, 'argument should be of type Error');
+    t.ok(e instanceof GulpUglifyError, 'argument should be of type GulpUglifyError');
+    t.equals(e.cause.msg, '`exportAll` is not a supported option');
     t.equal(e.plugin, 'gulp-uglify', 'error is from gulp-uglify');
     t.equal(e.fileName, testFile2.path, 'error reports correct file name');
     t.false(e.showStack, 'error is configured to not print the stack');

test/streams.js

@@ -2,7 +2,7 @@
 var Readable = require('stream').Readable;
 var test = require('tape');
 var Vinyl = require('vinyl');
-var PluginError = require('gulp-util/lib/PluginError');
+var GulpUglifyError = require('../lib/gulp-uglify-error');
 var gulpUglify = require('../');
 
 var testFile1 = new Vinyl({
@@ -21,12 +21,11 @@ test('should emit error for stream files', function (t) {
     t.fail('should emit error for streams');
   }).on('error', function (e) {
     t.pass('emitted error');
-    t.ok(e instanceof PluginError, 'error is a PluginError');
+    t.ok(e instanceof GulpUglifyError, 'error is a GulpUglifyError');
     t.equal(e.plugin, 'gulp-uglify', 'error is from gulp-uglify');
     t.equal(e.fileName, testFile1.path, 'error reports the correct file');
 
-    // t.ok(e.stack, 'error has a stack');
-    t.skip('error should have a stack');
+    t.ok(e.stack, 'error has a stack');
     t.false(e.showStack, 'error is configured to not print stack');
   });