Matthew Tomas Javascript I WIP

MatthewTomas · MatthewTomas · commit bc3db5e1be2c · 2018-02-20T18:08:39.000-05:00
diff --git a/src/arrays.js b/src/arrays.js
@@ -14,12 +14,16 @@ 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]);
+  }
 };
 
 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 reduce = (elements, cb, startingValue) => {
@@ -28,6 +32,12 @@ const reduce = (elements, cb, startingValue) => {
   // 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.
+  let memo = elements.shift();
+  if (startingValue !== undefined) memo = cb(memo, startingValue);
+  for (let i = 0; i < elements.length; i++) {
+    memo = cb(memo, elements[i]);
+  }
+  return memo;
 };
 
 const find = (elements, cb) => {
@@ -48,6 +58,15 @@ const filter = (elements, cb) => {
 const flatten = (elements) => {
   // Flattens a nested array (the nesting can be to any depth).
   // Example: flatten([1, [2], [3, [[4]]]]); => [1, 2, 3, 4];
+  let newArr = [];
+  for (let i = 0; i < elements.length; i++) {
+    if (Array.isArray(elements[i])) {
+      newArr = newArr.concat(flatten(elements[i]));
+    } else {
+      newArr.push(elements[i]);
+    }
+  }
+  return newArr;
 };
 
 /* eslint-enable no-unused-vars, max-len */
diff --git a/src/callbacks.js b/src/callbacks.js
@@ -1,21 +1,26 @@
 const firstItem = (arr, cb) => {
   // firstItem passes the first item of the given array to the callback function.
+  cb(arr[0]);
 };
 
 const getLength = (arr, cb) => {
   // getLength passes the length of the array into the callback.
+  cb(arr.length);
 };
 
 const last = (arr, cb) => {
   // last passes the last item of the array into the callback.
+  cb(arr[arr.length - 1]);
 };
 
 const sumNums = (x, y, cb) => {
   // sumNums adds two numbers (x, y) and passes the result to the callback.
+  cb(x + y);
 };
 
 const multiplyNums = (x, y, cb) => {
   // multiplyNums multiplies two numbers and passes the result to the callback.
+  cb(x * y);
 };
 
 const contains = (item, list, cb) => {
