Add initial implementation

API.md

@@ -50,14 +50,13 @@
 
 #### paginator.page
 
-This is a [getter][mdn-defineproperty] property.
-
-[mdn-defineproperty]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/defineProperty
+This is a property is read-only.
 
 ```javascript
 let paginator = new BasePaginator(request);
-// True
+
 paginator.page === 0;
+// -> true
 ```
 
 #### paginator.queryHandler
@@ -192,10 +191,10 @@ promise.then((mergedResponse) => {
 ```javascript
 let error = new PaginatorError('Something went wrong.');
 
-// True
 error instanceof PaginatorError;
-// True
+// -> true
 error instanceof Error;
+// -> true
 ```
 
 ## Paginators
@@ -226,8 +225,9 @@ new PageNumberPaginator(request[, requestOptions, queryParams]);
 ```javascript
 let queryParams = { page: 2 };
 let paginator = new PageNumberPaginator(request, null, queryParams);
-// True
+
 paginator.page === 2;
+// -> true
 ```
 
 ### LimitOffsetPaginator
@@ -241,8 +241,9 @@ new LimitOffsetPaginator(request[, requestOptions, queryParams]);
 ```javascript
 let queryParams = { limit: 50, offset: 50 };
 let paginator = new LimitOffsetPaginator(request, null, queryParams);
-// True
+
 paginator.page === 2;
+// -> true
 ```
 
 ## Query Handlers
@@ -275,8 +276,8 @@ _Example:_
 let options = { pageQueryParam: 'p' };
 let queryHandler = new PageNumberQueryHandler(options);
 let queryParams = queryHandler.makeParams(42);
-// True
 queryParams.p === 42;
+// -> true
 ```
 
 [drf-page-number-config]: http://www.django-rest-framework.org/api-guide/pagination/#configuration
@@ -320,10 +321,11 @@ let queryHandler = new LimitOffsetQueryHandler(options);
 queryHandler.setParams({ l: 50 });
 
 let queryParams = queryHandler.makeParams(3);
-// True
+
 queryParams.l === 50;
-// True
-queryParams.o === 100;
+// -> true
+queryParams.o === 100
+// -> true;
 ```
 
 ## Utility
@@ -373,7 +375,7 @@ import querystring from 'querystring';
 let request = function(options, queryParams) {
   let {user} = options;
   let query = querystring.stringify(queryParams);
-  let url = `https://example.com/users/${user/}?${query}`;
+  let url = `https://example.com/users/${user}?${query}`;
 
   return fetch(url)
     .then((response) => response.json());
@@ -399,37 +401,37 @@ import {requests} from 'user-image-service';
 /**
  * Create a paginator for the endpoint using an existing request function
  */
-const userPhotoUrls = new drfp.LimitOffsetPaginator(
-  requests.fetchPhotoUrls,
+const userImageUrls = new drfp.LimitOffsetPaginator(
+  requests.fetchImageUrls,
   { user: 'abc123' },
   { limit: 20 }
 );
 
 /**
  * Create a request function that retrieves and merges ten pages of results
  */
-const batchFetchPhotoUrls = function(options, queryParams) {
+const batchFetchImageUrls = function(options, queryParams) {
   const {page} = queryParams;
   const startPage = page * 10 - 9;
   const endPage = page * 10;
-  const pageMerger = new drfp.PageMerger(userPhotoUrls);
+  const pageMerger = new drfp.PageMerger(userImageUrls);
 
   return pageMerger.merge(startPage, endPage);
 };
 
 /**
- * Create a paginator for the new request function
+ * Create a paginator for the batch request function
  */
-let batchUserPhotoUrls = drfp.paginate(batchFetchPhotoUrls);
+const batchUserImageUrls = drfp.paginate(batchFetchImageUrls);
 
 const displayNextImages = function() {
-  return batchUserPhotoUrls.next()
-    .then(displayPhotos)
+  return batchUserImageUrls.next()
+    .then(displayImages)
     .catch(displayError);
 };
 
 /**
- * Display the first page of 200 images
+ * Display the first page of 200 Images
  */
-showNextImages();
+displayNextImages();
 ```

README.md

@@ -65,6 +65,11 @@ Please view the [API reference][api] for details and more examples.
 
 A [Promises/A+][promise-spec] compliant promise implementation must be available globally.
 
+Consumers using [Browserify](browserify) must have the [Babelify](babelify) transform.
+
+[babelify]: https://github.com/babel/babelify
+[browserify]: http://browserify.org/
+
 ## Installation
 
 Node.js via [npm](https://www.npmjs.com)
@@ -87,7 +92,7 @@ Install dependencies
 $ npm install
 ```
 
-Run tests and lint
+Run the test suite, generate coverage reports, and lint the source
 
 ```bash
 $ npm test
@@ -105,6 +110,12 @@ Run unit tests
 $ npm run unit
 ```
 
+Run the test suite, and generate coverage reports
+
+```bash
+$ npm run cover
+```
+
 Publish coverage report
 
 ```bash

package.json

@@ -7,10 +7,11 @@
   "license": "MIT",
   "main": "src/index.js",
   "scripts": {
+    "cover": "rm -rf coverage && babel-node node_modules/.bin/isparta cover --root src/ --report text --report lcov --report html node_modules/.bin/_mocha -- src/test-setup.js $(find src -name '*-spec.js')",
     "coveralls": "cat coverage/lcov.info | coveralls",
     "jshint": "jshint src",
-    "test": "karma start karma.unit.conf.js && jshint src",
-    "unit": "karma start karma.unit.conf.js"
+    "test": "npm run cover && npm run jshint",
+    "unit": "babel-node node_modules/.bin/_mocha --require src/test-setup.js --recursive src"
   },
   "keywords": [
     "django",
@@ -28,46 +29,37 @@
     "url": "https://github.com/yola/drf-paginator/issues"
   },
   "dependencies": {
+    "babel-preset-es2015": "~6.6.0",
     "lodash.assign": "~4.0.6",
     "lodash.clonedeep": "~4.3.2",
     "lodash.omit": "~4.1.0",
     "lodash.reduce": "~4.3.0"
   },
   "devDependencies": {
-    "babel-preset-es2015": "~6.6.0",
-    "babelify": "~7.2.0",
+    "app-module-path": "~1.0.6",
+    "babel-cli": "~6.7.5",
     "bluebird": "~3.3.4",
-    "browserify": "~13.0.0",
     "chai": "~3.5.0",
     "chai-as-promised": "~5.3.0",
     "coveralls": "~2.11.9",
+    "isparta": "~4.0.0",
     "jsgreat": "~0.1.8",
     "jshint": "~2.9.1",
-    "karma": "~0.13.22",
-    "karma-browserify": "~5.0.3",
-    "karma-coverage": "~0.5.5",
-    "karma-mocha": "~0.2.2",
-    "karma-phantomjs-launcher": "~1.0.0",
-    "karma-spec-reporter": "0.0.24",
     "mocha": "~2.4.5",
-    "phantomjs-prebuilt": "~2.1.6",
     "sinon": "~1.17.3",
-    "sinon-chai": "~2.8.0",
-    "watchify": "~3.7.0"
+    "sinon-chai": "~2.8.0"
+  },
+  "babel": {
+    "presets": [
+      "es2015"
+    ]
   },
   "browserify": {
     "paths": [
       "."
     ],
     "transform": [
-      [
-        "babelify",
-        {
-          "presets": [
-            "es2015"
-          ]
-        }
-      ]
+      "babelify"
     ]
   }
 }

src/actions-spec.js

@@ -0,0 +1,46 @@
+import chai from 'chai';
+
+import actions from 'src/actions';
+
+
+const {expect} = chai;
+
+describe('drf-paginator', function() {
+  const response = {
+    count: 0,
+    results: []
+  };
+
+  describe('actions', function() {
+    it('should export inferResponseLimit', function() {
+      expect(actions.inferResponseLimit).to.exist;
+    });
+
+    it('should export parseResponse', function() {
+      expect(actions.parseResponse).to.exist;
+    });
+
+    describe('inferResponseLimit', function() {
+      it('returns NULL when it can\'t determine the limit', function() {
+        const result = actions.inferResponseLimit(response);
+
+        expect(result).to.be.null;
+      });
+    });
+
+    describe('parseResponse', function() {
+      it('parses responses', function() {
+        const result = actions.parseResponse(response);
+
+        const expectedResult = {
+          count: 0,
+          limit: null,
+          pageCount: 1,
+          results: response.results
+        };
+
+        expect(result).to.eql(expectedResult);
+      });
+    });
+  });
+});

src/actions.js

@@ -1,6 +1,6 @@
-export const inferResponseLimit = function(data) {
-  const count = data.count;
-  const resultCount = data.results.length;
+export const inferResponseLimit = function(response) {
+  const count = response.count;
+  const resultCount = response.results.length;
 
   if (count > resultCount) {
     return resultCount;
@@ -9,9 +9,9 @@ export const inferResponseLimit = function(data) {
   return null;
 };
 
-export const parseResponse = function(data) {
-  const {count, results} = data;
-  const limit = inferResponseLimit(data);
+export const parseResponse = function(response) {
+  const {count, results} = response;
+  const limit = inferResponseLimit(response);
   let pageCount = 1;
 
   if (count && limit) {

src/helpers/request-spy.js

@@ -1,48 +1,18 @@
 import assign from 'lodash.assign';
 import sinon from 'sinon';
 
-import limitOffsetResponse from 'src/fixtures/limit-offset-response.json';
 import pageNumberResponse from 'src/fixtures/page-number-response.json';
 
 
 export const request = function(options, queryParams) {
   const uniqueValue = Math.random();
-  let fixture;
-
-  if (queryParams.hasOwnProperty('page')) {
-    fixture = pageNumberResponse;
-  } else {
-    fixture = limitOffsetResponse;
-  }
-
-  const response = assign({}, fixture, { uniqueValue });
+  const response = assign({}, pageNumberResponse, { uniqueValue });
 
   return Promise.resolve(response);
 };
 
 export const spy = sinon.spy(request);
 
-export const getArgs = function() {
-  const args = spy.args;
-  return args[args.length - 1];
-};
-
 export const getCallCount = function() {
   return spy.callCount;
 };
-
-export const getOptions = function() {
-  return getArgs()[0];
-};
-
-export const getQueryParams = function() {
-  return getArgs()[1];
-};
-
-export const getOffset = function() {
-  return getQueryParams().offset;
-};
-
-export const getPage = function() {
-  return getQueryParams().page;
-};

src/paginators/base-paginator-spec.js

@@ -1,5 +1,6 @@
 import chai from 'chai';
 import chaiAsPromised from 'chai-as-promised';
+import sinon from 'sinon';
 import sinonChai from 'sinon-chai';
 
 import {BasePaginator, errors} from 'src/paginators/base-paginator';
@@ -303,6 +304,11 @@ describe('drf-paginator', function() {
     describe('fetchPageCount', function() {
       beforeEach(function() {
         makePaginator();
+        sinon.spy(paginator, 'fetchPage');
+      });
+
+      afterEach(function() {
+        paginator.fetchPage.restore();
       });
 
       it('returns a promise that resolves', function() {
@@ -316,6 +322,14 @@ describe('drf-paginator', function() {
 
         return expect(pageCount).to.eventually.equal(10);
       });
+
+      it('caches the page count', function() {
+        const fetchPageCallCount = paginator.fetchPageCount()
+          .then(() => paginator.fetchPageCount())
+          .then(() => paginator.fetchPage.callCount);
+
+        return expect(fetchPageCallCount).to.eventually.equal(1);
+      });
     });
 
     describe('setQueryHandler', function() {

src/paginators/base-paginator.js

@@ -51,13 +51,15 @@ export class BasePaginator {
       return this._getRequest(page)
         .then(cloneDeep);
     }
+
     if (!this._isValidPage(page)) {
       return this._rejectPage(page);
     }
 
     const handleResponse = (response) => {
       return this._handleResponse(response, page);
     };
+
     const request = this._sendRequest(page)
       .then(handleResponse);
 

src/query-handlers/limit-offset-query-handler-spec.js

@@ -101,6 +101,26 @@ describe('drf-paginator', function() {
 
             expect(page).to.equal(42);
           });
+
+        it('throws an error if no limit is given',
+          function() {
+            const check = function() {
+              handler.resolvePage({
+                offset: 20500
+              });
+            };
+
+            expect(check).to.throw(PaginatorError);
+          });
+
+        it('resolves the first page without a limit being set',
+          function() {
+            const page = handler.resolvePage({
+              offset: 0
+            });
+
+            expect(page).to.equal(1);
+          });
       });
 
       describe('setParams', function() {
@@ -111,6 +131,37 @@ describe('drf-paginator', function() {
         });
       });
 
+      describe('onResponse', function() {
+        it('sets the limit query parameter if missing', function() {
+          const response = {
+            count: 10,
+            results: Array(2)
+          };
+          const page = 1;
+
+          handler.onResponse(response, page);
+
+          const queryParams = handler.makeParams(1);
+
+          expect(queryParams.limit).to.equal(2);
+        });
+
+        it('doesn\'t set the limit query parameter if the page isn\'t one',
+          function() {
+            const response = {
+              count: 10,
+              results: Array(2)
+            };
+            const page = 2;
+
+            handler.onResponse(response, page);
+
+            const queryParams = handler.makeParams(1);
+
+            expect(queryParams.limit).to.be.null;
+          });
+      });
+
       describe('setOptions', function() {
         it('is a fluent method', function() {
           var result = handler.setOptions({ hello: 'world' });

src/query-handlers/limit-offset-query-handler.js

@@ -17,6 +17,8 @@ const defaultOptions = {
 
 export class LimitOffsetQueryHandler {
   constructor(options) {
+    this._excessParams = null;
+    this._limit = null;
     this.setOptions(options);
   }
 
@@ -31,13 +33,17 @@ export class LimitOffsetQueryHandler {
   }
 
   resolvePage(queryParams) {
-    const result = this._parse(queryParams);
+    const {offset, limit} = this._parse(queryParams);
 
-    if (!this._limit) {
-      this._limit = result.limit;
+    if (offset === 0) {
+      return 1;
     }
 
-    return this._calculatePage(result.offset);
+    if (!limit) {
+      throw new PaginatorError(errors.calculatePageNoLimit);
+    }
+
+    return (offset + limit) / limit;
   }
 
   setParams(queryParams) {
@@ -48,10 +54,9 @@ export class LimitOffsetQueryHandler {
     return this;
   }
 
-  onResponse(response) {
-    const result = actions.parseResponse(response);
-
-    if (!this._limit) {
+  onResponse(response, page) {
+    if (page === 1 && !this._limit) {
+      const result = actions.parseResponse(response);
       this._limit = result.limit;
     }
   }
@@ -104,19 +109,6 @@ export class LimitOffsetQueryHandler {
 
     return limit * page - limit;
   }
-
-  _calculatePage(offset) {
-    const limit = this._limit;
-
-    if (offset === 0) {
-      return 1;
-    }
-    if (!limit) {
-      throw new PaginatorError(errors.calculatePageNoLimit);
-    }
-
-    return (offset + limit) / limit;
-  }
 }
 
 export default LimitOffsetQueryHandler;

src/query-handlers/page-number-query-handler.js

@@ -8,6 +8,7 @@ const defaultOptions = {
 
 export class PageNumberQueryHandler {
   constructor(options) {
+    this._excessParams = null;
     this.setOptions(options);
   }
 

src/test-setup.js

@@ -1,4 +1,6 @@
+import appModulePath from 'app-module-path';
 import bluebird from 'bluebird';
 
 
-window.Promise = bluebird;
+appModulePath.addPath(__dirname + '/..');
+global.Promise = bluebird;