feat: error if createLogger is passed to applyMiddleware (#204)

package.json

@@ -71,7 +71,9 @@
     "mocha": "3.1.2",
     "nyc": "9.0.1",
     "open-url": "2.0.2",
+    "redux": "^3.6.0",
     "rimraf": "2.5.4",
+    "sinon": "^1.17.7",
     "webpack": "1.13.3"
   },
   "dependencies": {

spec/index.spec.js

@@ -2,10 +2,40 @@ import { expect } from 'chai';
 
 import { repeat } from 'helpers';
 
+import { applyMiddleware, createStore } from 'redux';
+
+import sinon from 'sinon';
+
+import createLogger from '../src';
+
 context(`Helpers`, () => {
   describe(`'repeat'`, () => {
     it(`should repeat a string the number of indicated times`, () => {
       expect(repeat(`teacher`, 3)).to.equal(`teacherteacherteacher`);
     });
   });
 });
+
+context('createLogger', () => {
+  describe('initialization', () => {
+    beforeEach(() => {
+      sinon.spy(console, 'error');
+    });
+
+    afterEach(() => {
+      console.error.restore();
+    });
+
+    it('should log an error if the function is passed to applyMiddleware', () => {
+      const store = createStore(() => ({}), applyMiddleware(createLogger));
+      store.dispatch({ type: 'foo' });
+      sinon.assert.calledOnce(console.error);
+    });
+
+    it('should not log an error if the correct function is passed', () => {
+      const store = createStore(() => ({}), applyMiddleware(createLogger()));
+      store.dispatch({ type: 'foo' });
+      sinon.assert.notCalled(console.error);
+    });
+  });
+});

src/index.js

@@ -46,6 +46,22 @@ function createLogger(options = {}) {
     console.error(`Option 'transformer' is deprecated, use 'stateTransformer' instead!`); // eslint-disable-line no-console
   }
 
+  // Detect if 'createLogger' was passed directly to 'applyMiddleware'.
+  if (options.getState && options.dispatch) {
+    // eslint-disable-next-line no-console
+    console.error(`redux-logger not installed. Make sure to pass logger instance as middleware:
+
+import createLogger from 'redux-logger';
+
+const logger = createLogger();
+const store = createStore(
+  reducer,
+  applyMiddleware(logger)
+);`);
+
+    return () => next => action => next(action);
+  }
+
   const logBuffer = [];
 
   return ({ getState }) => (next) => (action) => {