problems not solved?

ala2233 · ala2233 · commit d74454b54392 · 2018-02-07T23:24:27.000-08:00
closure cacheFunction and object defualt creation
diff --git a/src/arrays.js b/src/arrays.js
@@ -1,9 +1,3 @@
-// Complete the following functions.
-// These functions only need to work with arrays.
-// Do NOT use the built in array methods to solve these. forEach, map, reduce, filter, includes, etc.
-// You CAN use concat, push, pop, etc. but do not use the exact method that you are replicating
-// You can use the functions that you have already written to help solve the other problems
-
 const each = (elements, cb) => {
   for (let i = 0; i < elements.length; i++) {
     cb(elements[i], i);
@@ -19,21 +13,18 @@ const map = (elements, cb) => {
 };
 
 const reduce = (elements, cb, startingValue) => {
-  const newElements = elements.slice(); // creating a new array
-  if (!startingValue) { // if its not pointing on the 1st element
-    startingValue = newElements.shift(); // shift return the 1st el
+  const newElements = elements.slice();
+  if (!startingValue) {
+    startingValue = newElements.shift();
   }
-  let memo = startingValue; // this is memoazation for the staringValue
-  each(newElements, (el) => { // run a forEach on el and a callback where memo refrence the cb
+  let memo = startingValue;
+  each(newElements, (el) => {
     memo = cb(memo, el);
   });
   return memo;
 };
 
 const find = (elements, cb) => {
-  // 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])) {
       return elements[i];
@@ -42,8 +33,6 @@ const find = (elements, cb) => {
 };
 
 const filter = (elements, cb) => {
-  // 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 newArr = [];
   for (let i = 0; i < elements.length; i++) {
     if (cb(elements[i])) {
@@ -56,10 +45,6 @@ const filter = (elements, cb) => {
 /* STRETCH PROBLEM */
 
 const flatten = (elements) => {
-  // Flattens a nested array (the nesting can be to any depth).
-  // Example: flatten([1, [2], [3, [[4]]]]); => [1, 2, 3, 4];
-  // const reducedArr = elements.reduce((a, n) => a.concat(n), []);
-  // return reducedArr;
   const newArr = [];
   Object.values(elements).forEach((e) => {
     if (typeof e === 'number') {
diff --git a/src/callbacks.js b/src/callbacks.js
@@ -21,8 +21,6 @@ const multiplyNums = (x, y, cb) => {
 };
 
 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++ ) {
     if (item === list[i]) return cb(true);
   }
@@ -32,9 +30,6 @@ const contains = (item, list, cb) => {
 /* 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.
   const newObj = {};
   Object.keys(array).map(key => newObj[array[key]] = array[key]);
   const newArr = Object.keys(newObj);
diff --git a/src/closure.js b/src/closure.js
@@ -1,18 +1,11 @@
 // Complete the following functions.
 
 const counter = () => {
-  // Return a function that when invoked increments and returns a counter variable.
-  // Example: const newCounter = counter();
-  // newCounter(); // 1
-  // newCounter(); // 2
   let count = 0;
   return () => ++count;
 };
 
 const counterFactory = () => {
-  // Return an object that has two methods called `increment` and `decrement`.
-  // `increment` should increment a counter variable in closure scope and return it.
-  // `decrement` should decrement the counter variable and return it.
   let fCounter = 0;
   return {
     increment() {
@@ -25,8 +18,6 @@ const counterFactory = () => {
 };
 
 const limitFunctionCallCount = (cb, n) => {
-  // Should return a function that invokes `cb`.
-  // The returned function should only allow `cb` to be invoked `n` times.
   return () => {
     for (let i = 0; i <= n; i++) {
       return cb();
diff --git a/src/objects.js b/src/objects.js
@@ -1,34 +1,19 @@
-// Complete the following underscore functions.
-// Reference http://underscorejs.org/ for examples.
-
 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
-  // array like object
   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) best solution!
   return Object.keys(obj).map(value => obj[value]);
 };
 
 const mapObject = (obj, cb) => {
-  // Like map for arrays, but for objects. Transform the value of each property in turn.
-  // http://underscorejs.org/#mapObject
   const newObj = {};
   Object.keys(obj).map(key => newObj[key] = obj[key]);
   return cb(newObj);
 };
 
 const pairs = (obj) => {
-  // Convert an object into a list of [key, value] pairs.
-  // http://underscorejs.org/#pairs
   const newArr = [];
   Object.keys(obj).map((key, i, arr) => newArr.push([arr[i], obj[key]]));
   return newArr;
@@ -37,9 +22,6 @@ const pairs = (obj) => {
 /* STRETCH PROBLEMS */
 
 const invert = (obj) => {
-  // Returns a copy of the object where the keys have become the values and the values the keys.
-  // Assume that all of the object's values will be unique and string serializable.
-  // http://underscorejs.org/#invert
   const newObj = {};
   Object.keys(obj).map((key, i, arr) => newObj[obj[key]] = arr[i]);
   return newObj;
