feat($interpolate): provide contextual error messages

if an exception occurs during interpolation of a string
(e.g. name() in "Hello, {{name()}}!" throws an exception) we now print
an error message with the expression that was being evaluated when the
exception was thrown.

2 files changed, 24 insertions, 1 deletions

diff --git a/test/BinderSpec.js b/test/BinderSpec.js
index 6d5dd91e..ba90539f 100644
--- a/test/BinderSpec.js
+++ b/test/BinderSpec.js
@@ -175,7 +175,7 @@ describe('Binder', function() {
       $rootScope.error['throw'] = function() {throw 'MyError';};
       errorLogs.length = 0;
       $rootScope.$apply();
-      expect(errorLogs.shift()).toBe('MyError');
+      expect(errorLogs.shift().message).toBe('Error while interpolating: {{error.throw()}}\nMyError');
 
       $rootScope.error['throw'] = function() {return 'ok';};
       $rootScope.$apply();
diff --git a/test/ng/interpolateSpec.js b/test/ng/interpolateSpec.js
index 20214445..a0a3e311 100644
--- a/test/ng/interpolateSpec.js
+++ b/test/ng/interpolateSpec.js
@@ -25,6 +25,29 @@ describe('$interpolate', function() {
     expect($interpolate('{{ false }}')()).toEqual('false');
   }));
 
+  it('should rethrow exceptions', inject(function($interpolate, $rootScope) {
+    $rootScope.err = function () {
+      throw new Error('oops');
+    };
+    expect(function () {
+      $interpolate('{{err()}}')($rootScope);
+    }).toThrow('Error while interpolating: {{err()}}\nError: oops');
+  }));
+
+  it('should stop interpolation when encountering an exception', inject(function($interpolate, $compile, $rootScope) {
+    $rootScope.err = function () {
+      throw new Error('oops');
+    };
+    var dom = jqLite('<div>{{1 + 1}}</div><div>{{err()}}</div><div>{{1 + 2}}</div>');
+    $compile(dom)($rootScope);
+    expect(function () {
+      $rootScope.$apply();
+    }).toThrow('Error while interpolating: {{err()}}\nError: oops');
+    expect(dom[0].innerHTML).toEqual('2');
+    expect(dom[1].innerHTML).toEqual('{{err()}}');
+    expect(dom[2].innerHTML).toEqual('{{1 + 2}}');
+  }));
+
 
   it('should return interpolation function', inject(function($interpolate, $rootScope) {
     $rootScope.name = 'Misko';