JS-I&II Push 1

src/arrays.js

@@ -14,33 +14,63 @@ const each = (elements, cb) => {
   // This only needs to work with arrays.
   // You should also pass the index into `cb` as the second argument
   // based off http://underscorejs.org/#each
+
+  for (let i = 0; i < elements.length; i++) {
+    cb(elements[i], i);
+  }
 };
 
+
 const map = (elements, cb) => {
   // Do NOT use .map, to complete this function.
   // Produces a new array of values by mapping each value in list through a transformation function (iteratee).
   // Return the new array.
+  const myMap = [];
+  for (let i = 0; i < elements.length; i++) {
+    myMap.push(cb(elements[i]));
+  }
+  return myMap;
 };
 
+
 const reduce = (elements, cb, startingValue) => {
   // Do NOT use .reduce, to complete this function.
   // Combine all elements into a single value going from left to right.
   // Elements will be passed one by one into `cb` along with the `startingValue`.
   // `startingValue` should be the first argument passed to `cb` and the array element should be the second argument.
   // `startingValue` is the starting value.  If `startingValue` is undefined then make `elements[0]` the initial value.
+  if (startingValue === undefined) {
+    startingValue = elements[0];
+  }
+  for (let i = startingValue; i < elements.length; i++) {
+    startingValue = cb(startingValue, elements[i]);
+  }
+  return startingValue;
 };
 
 const find = (elements, cb) => {
   // Do NOT use .includes, to complete this function.
   // Look through each value in `elements` and pass each element to `cb`.
   // If `cb` returns `true` then return that element.
   // Return `undefined` if no elements pass the truth test.
+  for (let i = 0; i < elements.length; i++) {
+    if (cb(elements[i]) === true) {
+      return elements[i];
+    }
+  } return undefined;
 };
 
+
 const filter = (elements, cb) => {
   // Do NOT use .filter, to complete this function.
   // Similar to `find` but you will return an array of all elements that passed the truth test
   // Return an empty array if no elements pass the truth test
+  const newFilter = [];
+  for (let i = 0; i < elements.length; i++) {
+    if (cb(elements[i]) === true) {
+      newFilter.push(elements[i]);
+    }
+  } return newFilter;
 };
 
 /* STRETCH PROBLEM */

src/callbacks.js

@@ -1,26 +1,34 @@
 const firstItem = (arr, cb) => {
   // firstItem passes the first item of the given array to the callback function.
+  return cb(arr[0]);
 };
 
 const getLength = (arr, cb) => {
   // getLength passes the length of the array into the callback.
+  return cb(arr.length);
 };
 
 const last = (arr, cb) => {
   // last passes the last item of the array into the callback.
+  return cb(arr[arr.length - 1]);
 };
 
 const sumNums = (x, y, cb) => {
   // sumNums adds two numbers (x, y) and passes the result to the callback.
+  return cb(x + y);
 };
 
 const multiplyNums = (x, y, cb) => {
   // multiplyNums multiplies two numbers and passes the result to the callback.
+  return cb(x * y);
 };
 
 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.
+  for (let i = 0; i < list.length; i++) {
+    cb(item === list[i]);
+  }
 };
 
 /* STRETCH PROBLEM */

src/objects.js

@@ -5,17 +5,24 @@ const keys = (obj) => {
   // Retrieve all the names of the object's properties.
   // Return the keys as strings in an array.
   // Based on http://underscorejs.org/#keys
+  return Object.keys(obj);
 };
 
 const values = (obj) => {
   // Return all of the values of the object's own properties.
   // Ignore functions
   // http://underscorejs.org/#values
+  return Object.values(obj);
 };
 
 const mapObject = (obj, cb) => {
   // Like map for arrays, but for objects. Transform the value of each property in turn.
   // http://underscorejs.org/#mapObject
+  const myMap = {};
+  for (let i = 0; i < obj.length; i++) {
+    myMap.push(obj[i]);
+  }
+  cb(myMap);
 };
 
 const pairs = (obj) => {