Merge pull request bloominstituteoftechnology#46 from LambdaSchool/callbacks-refactor

Ryan Hamblin · web-flow · commit b155e6d1ac3e · 2017-11-04T09:24:00.000-06:00
Callbacks refactor
diff --git a/.eslintrc.json b/.eslintrc.json
@@ -1,20 +1,18 @@
 {
-    "extends": "airbnb-base",
-    "plugins": [
-        "import"
-    ],
+  "extends": "airbnb-base",
+  "plugins": ["import"],
+  "consistent-return": 0,
+  "rules": {
+    "no-param-reassign": 0,
+    "max-len": 0,
+    "no-plusplus": 0,
+    "linebreak-style": 0,
     "consistent-return": 0,
-    "rules": {
-      "no-param-reassign": 0,
-      "max-len": 0,
-      "no-plusplus": 0,
-      "linebreak-style": 0,
-      "consistent-return": 0,
-      "no-useless-return": 0,
-      "no-return-assign": 0,
-      "arrow-body-style": 0,
-      "no-unused-vars": 0,
-      "no-useless-constructor": 0,
-      "import/no-unresolved": 0
-    }
+    "no-useless-return": 0,
+    "no-return-assign": 0,
+    "arrow-body-style": 0,
+    "no-unused-vars": 0,
+    "no-useless-constructor": 0,
+    "import/no-unresolved": 0
+  }
 }
diff --git a/package-lock.json b/package-lock.json
diff --git a/src/callbacks.js b/src/callbacks.js
@@ -1,83 +1,43 @@
 /* eslint-disable */
 
-/*  For a portion of the assignment your job is to write functions
- *  so that each function invocation below works.  You're working backwards.
- *
- *  There are no tests for this file.
- *
- *  Example:
- *
- *  greeting('Hey guys', (message) => {
- *     console.log(message);
- *  });
- *
- *  You would then define the greeting function to make the invocation work.
- *
- *
- *  const greeting = (str, cb) => {
- *    cb(str);
- *  };
- *
- */
-
-// Write a function called firstItem that passes the first item of the given array to the callback function
-// code here
-
-const foods = ['pineapple', 'mango', 'ribeye', 'curry', 'tacos', 'ribeye', 'mango'];
-
-firstItem(foods, (firstItem) => {
-  console.log(`The first item is ${firstItem}.`);
-});
-
-// Write a function called getLength that passes the length of the array into the callback
-// code here
-
-getLength(foods, (length) => {
-  console.log(`The length of the array is ${length}.`);
-});
-
-// Write a function called last which passes the last item of the array into the callback
-// code here
-
-last(foods, (lastItem) => {
-  console.log(`The last item in the array is ${lastItem}.`);
-});
-
-// Write a function called sumNums that adds two numbers and passes the result to the callback
-// code here
-
-sumNums(5, 10, (sum) => {
-  console.log(`The sum is ${sum}.`);
-});
-
-// Write a function called multiplyNums that multiplies two numbers and passes the result to the callback
-// code here
-
-multiplyNums(5, 10, (product) => {
-  console.log(`The product is ${product}.`);
-});
-
-// Write a function called contains that checks if an item is present inside of the given array.
-// Pass true to the callback if it is, otherwise pass false
-// code here
-
-contains(foods, 'ribeye', (result) => {
-  console.log(result ? 'ribeye is in the array' : 'ribeye is not in the array');
-});
-
-// Write a function called removeDuplicates that removes all duplicate values from the given array.
-// Pass the array to the callback function.  Do not mutate the original array.
-// code here
-
-removeDuplicates(foods, (uniqueFoods) => {
-  console.log(`foods with duplicates removed: ${uniqueFoods}`);
-});
-
-// Write a function called forEach that iterates over the provided array and passes the value and index into the callback.
-// code here
-
-forEach(foods, (value, index) => {
-  console.log(`${value} is at index ${index}.`);
-});
+const firstItem = (arr, cb) => {
+  // firstItem passes the first item of the given array to the callback function.
+};
+
+const getLength = (arr, cb) => {
+  // getLength passes the length of the array into the callback.
+};
+
+const last = (arr, cb) => {
+  // last passes the last item of the array into the callback.
+};
+
+const sumNums = (x, y, cb) => {
+  // sumNums adds two numbers (x, y) and passes the result to the callback.
+};
+
+const multiplyNums = (x, y, cb) => {
+  // multiplyNums multiplies two numbers and passes the result to the callback.
+};
+
+const contains = (item, list, cb) => {
+  // contains checks if an item is present inside of the given array/list.
+  // Pass true to the callback if it is, otherwise pass false.
+};
+/* STRETCH PROBLEM */
+const removeDuplicates = (array, cb) => {
+  // removeDuplicates removes all duplicate values from the given array.
+  // Pass the duplicate free array to the callback function.
+  // Do not mutate the original array.
+};
 
 /* eslint-enable */
+module.exports = {
+  firstItem,
+  getLength,
+  last,
+  sumNums,
+  multiplyNums,
+  contains,
+  removeDuplicates,
+};
diff --git a/tests/callbacks.test.js b/tests/callbacks.test.js
@@ -0,0 +1,114 @@
+const callBackMethods = require('../src/callbacks');
+/* eslint-disable no-undef */
+
+describe('callback functions', () => {
+  const listOfFood = [
+    'cheetoes',
+    'bananas',
+    'turkey leg',
+    'cobbler',
+    'bananas',
+  ];
+
+  describe('firstItem', () => {
+    it('should pass the first item in the list to the callBack', () => {
+      let itemToTest;
+      callBackMethods.firstItem(listOfFood, (first) => {
+        itemToTest = first;
+      });
+      expect(itemToTest).toBe(listOfFood[0]);
+    });
+    it('should call the callback with the expected input', () => {
+      const mock = jest.fn();
+      callBackMethods.firstItem(listOfFood, mock);
+      expect(mock).toBeCalledWith('cheetoes');
+    });
+  });
+
+  describe('getLength', () => {
+    it('should pass back the length of the array to the callback', () => {
+      let len = 0;
+      callBackMethods.getLength(listOfFood, (length) => {
+        len = length;
+      });
+      expect(len).toBe(5);
+    });
+    it('should call the callback with the expected input', () => {
+      const mock = jest.fn();
+      callBackMethods.getLength(listOfFood, mock);
+      expect(mock).toBeCalledWith(5);
+    });
+  });
+
+  describe('last', () => {
+    it('should pass back the last item in the array to the callback', () => {
+      let item;
+      callBackMethods.last(listOfFood, (lastItem) => {
+        item = lastItem;
+      });
+      expect(item).toBe('bananas');
+    });
+    it('should call the given callback with the expected input', () => {
+      const mock = jest.fn();
+      callBackMethods.last(listOfFood, mock);
+      expect(mock).toBeCalledWith('bananas');
+    });
+  });
+
+  describe('sumNums', () => {
+    it('should pass back the result of the added nums to the callback', () => {
+      let result = 0;
+      callBackMethods.sumNums(10, 20, (res) => {
+        result = res;
+      });
+      expect(result).toBe(30);
+    });
+    it('should call the given callback with the expected input', () => {
+      const mock = jest.fn();
+      callBackMethods.sumNums(11, 22, mock);
+      expect(mock).toBeCalledWith(33);
+    });
+  });
+
+  describe('multiplyNums', () => {
+    it('should pass back the result of the multiplied nums to the callback', () => {
+      let result = 0;
+      callBackMethods.multiplyNums(10, 20, (res) => {
+        result = res;
+      });
+      expect(result).toBe(200);
+    });
+    it('should call the given callback with the expected input', () => {
+      const mock = jest.fn();
+      callBackMethods.multiplyNums(5, 11, mock);
+      expect(mock).toBeCalledWith(55);
+    });
+  });
+
+  describe('contains', () => {
+    it('should pass back true if item is in array', () => {
+      let flag;
+      callBackMethods.contains('bananas', listOfFood, (truf) => {
+        flag = truf;
+      });
+      expect(flag).toBe(true);
+    });
+    it('should pass back false if item is NOT in array', () => {
+      let flag;
+      callBackMethods.contains('boat', listOfFood, (truf) => {
+        flag = truf;
+      });
+      expect(flag).toBe(false);
+    });
+  });
+
+  describe('removeDuplicates', () => {
+    it('should remove any duplicate items from the array', () => {
+      let arrToTest = [];
+      callBackMethods.removeDuplicates(listOfFood, (arrayFreeOfDups) => {
+        arrToTest = arrayFreeOfDups;
+      });
+      expect(arrToTest.length).toBe(4);
+    });
+  });
+});
