ADD warning for decorators added "mid-kind"

examples/angular-cli/src/stories/component-with-di/di.component.stories.ts

@@ -9,10 +9,15 @@ storiesOf('Custom|Dependencies', module)
       title: 'Component dependencies',
     },
   }))
-  .addDecorator(withKnobs)
-  .add('inputs and inject dependencies with knobs', () => ({
-    component: DiComponent,
-    props: {
-      title: text('title', 'Component dependencies'),
-    },
-  }));
+  .add(
+    'inputs and inject dependencies with knobs',
+    () => ({
+      component: DiComponent,
+      props: {
+        title: text('title', 'Component dependencies'),
+      },
+    }),
+    {
+      decorators: [withKnobs],
+    }
+  );

examples/angular-cli/src/stories/custom-pipes.stories.ts

@@ -19,10 +19,15 @@ storiesOf('Custom|Pipes', module)
       field: 'foobar',
     },
   }))
-  .addDecorator(withKnobs)
-  .add('With Knobs', () => ({
-    component: NameComponent,
-    props: {
-      field: text('field', 'foobar'),
-    },
-  }));
+  .add(
+    'With Knobs',
+    () => ({
+      component: NameComponent,
+      props: {
+        field: text('field', 'foobar'),
+      },
+    }),
+    {
+      decorators: [withKnobs],
+    }
+  );

examples/angular-cli/src/stories/custom-providers.stories.ts

@@ -19,14 +19,19 @@ storiesOf('Custom|Providers', module)
       name: 'Static name',
     },
   }))
-  .addDecorator(withKnobs)
-  .add('With knobs', () => {
-    const name = text('name', 'Dynamic knob');
+  .add(
+    'With knobs',
+    () => {
+      const name = text('name', 'Dynamic knob');
 
-    return {
-      component: ServiceComponent,
-      props: {
-        name,
-      },
-    };
-  });
+      return {
+        component: ServiceComponent,
+        props: {
+          name,
+        },
+      };
+    },
+    {
+      decorators: [withKnobs],
+    }
+  );

examples/angular-cli/src/stories/custom-styles.stories.ts

@@ -24,19 +24,24 @@ storiesOf('Custom|Style', module)
     `,
     ],
   }))
-  .addDecorator(withKnobs)
-  .add('With Knobs', () => ({
-    template: `<storybook-button-component [text]="text" (onClick)="onClick($event)"></storybook-button-component>`,
-    props: {
-      text: text('text', 'Button with custom styles'),
-      onClick: action('log'),
-    },
-    styles: [
-      `
+  .add(
+    'With Knobs',
+    () => ({
+      template: `<storybook-button-component [text]="text" (onClick)="onClick($event)"></storybook-button-component>`,
+      props: {
+        text: text('text', 'Button with custom styles'),
+        onClick: action('log'),
+      },
+      styles: [
+        `
       storybook-button-component {
         background-color: red;
         padding: 25px;
       }
     `,
-    ],
-  }));
+      ],
+    }),
+    {
+      decorators: [withKnobs],
+    }
+  );

lib/client-api/src/client_api.js

@@ -134,6 +134,7 @@ export default class ClientApi {
 
     const localDecorators = [];
     let localParameters = {};
+    let hasAdded = false;
     const api = {
       kind,
     };
@@ -148,6 +149,7 @@ export default class ClientApi {
     });
 
     api.add = (storyName, storyFn, parameters) => {
+      hasAdded = true;
       const { _globalParameters, _globalDecorators } = this;
       const id = toId(kind, storyName);
 
@@ -215,6 +217,12 @@ export default class ClientApi {
     };
 
     api.addDecorator = decorator => {
+      if (hasAdded) {
+        console.warn(`You have added a decorator to the kind '${kind}' after a story has already been added.
+In Storybook 4 this applied the decorator only to subsequent stories. In Storybook 5+ it applies to all stories.
+This is probably not what you intended. Read more here: https://github.com/storybooks/storybook/blob/master/MIGRATION.md`);
+      }
+
       localDecorators.push(decorator);
       return api;
     };