Improved error messages for custom types (#162)

Author: schmidt-sebastian

src/document.js

@@ -1399,7 +1399,9 @@ function validateFieldValue(val, options, depth) {
   } else if (is.instanceof(val, GeoPoint)) {
     return true;
   } else if (is.instanceof(val, FieldPath)) {
-    throw new Error('Cannot use "FieldPath" as a Firestore type.');
+    throw new Error(
+      'Cannot use object of type "FieldPath" as a Firestore value.'
+    );
   } else if (is.object(val)) {
     throw validate.customObjectError(val);
   }

src/validate.js

@@ -141,21 +141,29 @@ module.exports = validators => {
   };
 
   exports.customObjectError = val => {
-    let typeName = is.object(val) ? val.constructor.name : typeof val;
-
-    switch (typeName) {
-      case 'DocumentReference':
-      case 'FieldPath':
-      case 'FieldValue':
-      case 'GeoPoint':
-        return new Error(
-          `Detected an object of type "${typeName}" that doesn't match the expected instance. Please ensure that ` +
-            'the Firestore types you are using are from the same NPM package.'
-        );
-      default:
-        return new Error(
-          `Cannot use custom type "${typeName}" as a Firestore type.`
-        );
+    if (is.object(val) && val.constructor.name !== 'Object') {
+      const typeName = val.constructor.name;
+      switch (typeName) {
+        case 'DocumentReference':
+        case 'FieldPath':
+        case 'FieldValue':
+        case 'GeoPoint':
+          return new Error(
+            `Detected an object of type "${typeName}" that doesn't match the ` +
+              'expected instance. Please ensure that the Firestore types you ' +
+              'are using are from the same NPM package.'
+          );
+        default:
+          return new Error(
+            `Couldn't serialize object of type "${typeName}". Firestore ` +
+              "doesn't support JavaScript objects with custom prototypes " +
+              "(i.e. objects that were created via the 'new' operator)."
+          );
+      }
+    } else {
+      return new Error(
+        `Invalid use of type "${typeof val}" as a Firestore argument.`
+      );
     }
   };
 

test/document.js

@@ -290,13 +290,18 @@ describe('serialize document', function() {
   it("doesn't serialize unsupported types", function() {
     assert.throws(() => {
       firestore.doc('collectionId/documentId').set({foo: undefined});
-    }, /Cannot use custom type "undefined" as a Firestore type./);
+    }, /Invalid use of type "undefined" as a Firestore argument./);
 
     assert.throws(() => {
       firestore
         .doc('collectionId/documentId')
         .set({foo: Firestore.FieldPath.documentId()});
-    }, /Cannot use "FieldPath" as a Firestore type./);
+    }, /Cannot use object of type "FieldPath" as a Firestore value./);
+
+    assert.throws(() => {
+      class Foo {}
+      firestore.doc('collectionId/documentId').set({foo: new Foo()});
+    }, /Argument "data" is not a valid Document. Couldn't serialize object of type "Foo". Firestore doesn't support JavaScript objects with custom prototypes \(i.e. objects that were created via the 'new' operator\)./);
   });
 
   it('serializes date before 1970', function() {
@@ -780,7 +785,7 @@ describe('get document', function() {
       .then(doc => {
         assert.throws(() => {
           doc.get();
-        }, /Argument "field" is not a valid FieldPath. Cannot use custom type "undefined" as a Firestore type./);
+        }, /Argument "field" is not a valid FieldPath. Invalid use of type "undefined" as a Firestore argument./);
       });
   });
 });

test/order.js

@@ -85,7 +85,7 @@ describe('Order', function() {
   it('throws on invalid value', function() {
     assert.throws(() => {
       order.compare({}, {});
-    }, /Cannot use custom type "Object" as a Firestore type/);
+    }, /Invalid use of type "object" as a Firestore argument./);
   });
 
   it('throws on invalid blob', function() {

test/query.js

@@ -709,7 +709,7 @@ describe('where() interface', function() {
       let query = firestore.collection('collectionId');
       query = query.where({}, '=', 'bar');
       return query.get();
-    }, /Argument "fieldPath" is not a valid FieldPath. Cannot use custom type "Object" as a Firestore type./);
+    }, /Argument "fieldPath" is not a valid FieldPath. Invalid use of type "object" as a Firestore argument/);
 
     class FieldPath {}
     assert.throws(() => {
@@ -724,7 +724,7 @@ describe('where() interface', function() {
       let query = firestore.collection('collectionId');
       query = query.where('foo', '=', new Firestore.FieldPath('bar'));
       return query.get();
-    }, /Argument "value" is not a valid FieldValue. Cannot use "FieldPath" as a Firestore type./);
+    }, /Argument "value" is not a valid FieldValue. Cannot use object of type "FieldPath" as a Firestore value./);
   });
 
   it('rejects field transforms as value', function() {
@@ -752,7 +752,7 @@ describe('where() interface', function() {
 
     assert.throws(() => {
       query.where('foo', '=', new Foo()).get();
-    }, /Argument "value" is not a valid FieldValue. Cannot use custom type "Foo" as a Firestore type./);
+    }, /Argument "value" is not a valid FieldValue. Couldn't serialize object of type "Foo". Firestore doesn't support JavaScript objects with custom prototypes \(i.e. objects that were created via the 'new' operator\)./);
 
     assert.throws(() => {
       query.where('foo', '=', new FieldPath()).get();
@@ -1039,7 +1039,7 @@ describe('select() interface', function() {
     let query = firestore.collection('collectionId');
     assert.throws(function() {
       query.select(1);
-    }, /Argument at index 0 is not a valid FieldPath. Cannot use custom type "number" as a Firestore type./);
+    }, /Argument at index 0 is not a valid FieldPath. Invalid use of type "number" as a Firestore argument./);
 
     assert.throws(function() {
       query.select('.');