Intial commit

Maxjoeld · Maxjoeld · commit e485014e2bd0 · 2018-01-10T10:56:40.000-05:00
diff --git a/src/arrays.js b/src/arrays.js
@@ -5,38 +5,81 @@
 // 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);
+  }
   // Iterates over a list of elements, yielding each in turn to the `cb` function.
   // 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
 };
 
 const map = (elements, cb) => {
+  const mappedArr = [];
+  for (let i = 0; i < elements.length; i++) {
+    const ele = cb(elements[i], i);
+    mappedArr.push(ele);
+  }
+  return mappedArr;
   // 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) => {
+  let memo = startingValue;
+  let start = 0;
+  if (memo === undefined) {
+    memo = elements[0];
+    start = 1;
+  }
+  for (let i = start; i < elements.length; i++) {
+    memo = cb(memo, elements[i]);
+  }
+  return memo;
   // 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.
 };
 
 const find = (elements, cb) => {
+  for (let i = 0; i < elements.length; i++) {
+    if (cb(elements[i])) {
+      return elements[i];
+    }
+  }
+  return undefined;
   // 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.
 };
 
 const filter = (elements, cb) => {
+  const result = [];
+  for (let i = 0; i < elements.length; i++) {
+    const ele = elements[i];
+    if (cb(ele)) {
+      result.push(ele);
+    }
+  }
+  return result;
   // 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
 };
 
 /* STRETCH PROBLEM */
 
 const flatten = (elements) => {
+  let flatArr = [];
+  for (let i = 0; i < elements.length; i++) {
+    const ele = elements[i];
+    if (Array.isArray(ele)) {
+      flatArr = flatArr.concat(flatten(ele));
+    } else {
+      flatArr.push(ele);
+    }
+  }
+  return flatArr;
   // Flattens a nested array (the nesting can be to any depth).
   // Example: flatten([1, [2], [3, [[4]]]]); => [1, 2, 3, 4];
 };
diff --git a/src/callbacks.js b/src/callbacks.js
@@ -1,33 +1,48 @@
 /* eslint-disable */
 
 const firstItem = (arr, cb) => {
+  cb(arr[0]);
   // firstItem passes the first item of the given array to the callback function.
 };
 
 const getLength = (arr, cb) => {
+  cb(arr.length);
   // getLength passes the length of the array into the callback.
 };
 
 const last = (arr, cb) => {
+  cb(arr[arr.length - 1]);
   // last passes the last item of the array into the callback.
 };
 
 const sumNums = (x, y, cb) => {
+  const sum = x + y;
+  cb(sum);
   // sumNums adds two numbers (x, y) and passes the result to the callback.
 };
 
 const multiplyNums = (x, y, cb) => {
+  const product = x * y;
+  cb(product);
   // multiplyNums multiplies two numbers and passes the result to the callback.
 };
 
 const contains = (item, list, cb) => {
+  return cb(list.includes(item));
   // 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) => {
+  const newArr = [];
+  for (let i = 0; i < array.length; i++) {
+    const ele = array[i];
+    if(newArr.indexOf(ele) < 0) {
+      newArr.push(ele)}
+   };
+   return cb(newArr)
   // removeDuplicates removes all duplicate values from the given array.
   // Pass the duplicate free array to the callback function.
   // Do not mutate the original array.
diff --git a/src/closure.js b/src/closure.js
@@ -1,27 +1,55 @@
 // Complete the following functions.
 
 const counter = () => {
+  let count = 0;
+  return function () {
+    return ++count;
+  };
   // Return a function that when invoked increments and returns a counter variable.
   // Example: const newCounter = counter();
   // newCounter(); // 1
   // newCounter(); // 2
 };
+// 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.
 
 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 count = 0;
+  return {
+    increment: () => {
+      return ++count;
+    },
+    decrement: () => {
+      return --count;
+    },
+  };
 };
 
 const limitFunctionCallCount = (cb, n) => {
+  let count = 0;
+  return (...args) => {
+    if (count < n) {
+      count++;
+      return cb(...args);
+    }
+    return null;
+  };
   // Should return a function that invokes `cb`.
   // The returned function should only allow `cb` to be invoked `n` times.
 };
 
 /* STRETCH PROBLEM */
 
 const cacheFunction = (cb) => {
-  // Should return a funciton that invokes `cb`.
+  const cache = {};
+  return (args) => {
+    if (!(args in cache)) {
+      cache[args] = cb(args);
+    }
+    return cache[args];
+  };
+  // Should return a funciton that invokes `cb`. check
   // A cache (object) should be kept in closure scope.
   // The cache should keep track of all arguments have been used to invoke this function.
   // If the returned function is invoked with arguments that it has already seen
diff --git a/src/objects.js b/src/objects.js
@@ -2,36 +2,60 @@
 // Reference http://underscorejs.org/ for examples.
 
 const keys = (obj) => {
+  const props = Object.keys(obj);
+  return props;
   // Retrieve all the names of the object's properties.
   // Return the keys as strings in an array.
   // Based on http://underscorejs.org/#keys
 };
 
 const values = (obj) => {
+  const valOfProp = Object.values(obj);
+  return valOfProp;
   // Return all of the values of the object's own properties.
   // Ignore functions
   // http://underscorejs.org/#values
 };
 
 const mapObject = (obj, cb) => {
+  Object.keys(obj).forEach(key => (obj[key] = cb(obj[key])));
+  return obj;
   // Like map for arrays, but for objects. Transform the value of each property in turn.
   // http://underscorejs.org/#mapObject
 };
 
 const pairs = (obj) => {
+  const result = [];
+  // Object.keys(obj).forEach(key => (result.push[key, obj[key]]));
+  Object.keys(obj).forEach((key) => {
+    const pair = [key, obj[key]];
+    result.push(pair);
+  });
+  return result;
   // Convert an object into a list of [key, value] pairs.
   // http://underscorejs.org/#pairs
 };
 
 /* STRETCH PROBLEMS */
 
 const invert = (obj) => {
+  const newObj = {};
+  Object.keys(obj).forEach((key) => {
+    newObj[obj[key]] = key;
+  });
+  return newObj;
   // 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 defaults = (obj, defaultProps) => {
+  Object.keys(defaultProps).forEach((key) => {
+    if (obj[key] === undefined) {
+      obj[key] = defaultProps[key];
+    }
+  });
+  return obj;
   // Fill in undefined properties that match properties on the `defaultProps` parameter object.
   // Return `obj`.
   // http://underscorejs.org/#defaults
