api: improve register transform logging and tests

Author: etpinard

src/plot_api/register.js

@@ -69,12 +69,22 @@ function registerTransformModule(newModule) {
         throw new Error(prefix + ' is missing a *transform* or *calcTransform* method.');
     }
 
+    // For more info, see:
+    // https://github.com/plotly/plotly.js/pull/978#pullrequestreview-2403353
+    if(hasTransform && hasCalcTransform) {
+        Lib.log([
+            prefix + ' has both a *transform* and *calcTransform* methods.',
+            'Please note that all *transform* methods are executed',
+            'before all *calcTransform* methods.'
+        ].join(' '));
     }
+
     if(!Lib.isPlainObject(newModule.attributes)) {
         Lib.log(prefix + ' registered without an *attributes* object.');
     }
+
     if(typeof newModule.supplyDefaults !== 'function') {
-        Lib.log(prefix + ' registered without a *supplyDefaults* function.');
+        Lib.log(prefix + ' registered without a *supplyDefaults* method.');
     }
 
     Registry.transformsRegistry[newModule.name] = newModule;

test/jasmine/tests/register_test.js

@@ -206,9 +206,11 @@ describe('the register function', function() {
         expect(function() {
             Plotly.register([invalidTrace]);
         }).toThrowError(Error, 'Invalid module was attempted to be registered!');
+
+        expect(Registry.transformsRegistry['mah-transform']).toBeUndefined();
     });
 
-    it('should throw when if transform module is invalid', function() {
+    it('should throw when if transform module is invalid (1)', function() {
         var missingTransformName = {
             moduleType: 'transform'
         };
@@ -217,15 +219,23 @@ describe('the register function', function() {
             Plotly.register(missingTransformName);
         }).toThrowError(Error, 'Transform module *name* must be a string.');
 
+        expect(Registry.transformsRegistry['mah-transform']).toBeUndefined();
+    });
+
+    it('should throw when if transform module is invalid (2)', function() {
         var missingTransformFunc = {
             moduleType: 'transform',
             name: 'mah-transform'
         };
 
         expect(function() {
             Plotly.register(missingTransformFunc);
-        }).toThrowError(Error, 'Transform module mah-transform is missing a *transform* function.');
+        }).toThrowError(Error, 'Transform module mah-transform is missing a *transform* or *calcTransform* method.');
+
+        expect(Registry.transformsRegistry['mah-transform']).toBeUndefined();
+    });
 
+    it('should not throw when transform module is valid (1)', function() {
         var transformModule = {
             moduleType: 'transform',
             name: 'mah-transform',
@@ -238,4 +248,33 @@ describe('the register function', function() {
 
         expect(Registry.transformsRegistry['mah-transform']).toBeDefined();
     });
+
+    it('should not throw when transform module is valid (2)', function() {
+        var transformModule = {
+            moduleType: 'transform',
+            name: 'mah-transform',
+            calcTransform: function() {}
+        };
+
+        expect(function() {
+            Plotly.register(transformModule);
+        }).not.toThrow();
+
+        expect(Registry.transformsRegistry['mah-transform']).toBeDefined();
+    });
+
+    it('should not throw when transform module is valid (3)', function() {
+        var transformModule = {
+            moduleType: 'transform',
+            name: 'mah-transform',
+            transform: function() {},
+            calcTransform: function() {}
+        };
+
+        expect(function() {
+            Plotly.register(transformModule);
+        }).not.toThrow();
+
+        expect(Registry.transformsRegistry['mah-transform']).toBeDefined();
+    });
 });