completed

Troy Williams · Troy Williams · commit 579f98f8ec66 · 2017-12-05T18:54:41.000-06:00
diff --git a/src/arrays.js b/src/arrays.js
@@ -9,38 +9,101 @@ 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) => {
   // Produces a new array of values by mapping each value in list through a transformation function (iteratee).
   // Return the new array.
+  const newArr = [];
+  each(elements, (item, index) => {
+    newArr.push(cb(item, index));
+  });
+  return newArr;
 };
 
 const reduce = (elements, cb, startingValue) => {
+  // arr, (memo, num) => (memo + num)
   // 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.
+  // let reduced;
+  // if (startingValue === undefined) {
+  //   reduced = elements[0];
+  //   for (let i = 1; i < elements.length; i++) {
+  //     reduced = cb(reduced, elements[i]);
+  //   }
+  // } else {
+  //   reduced = startingValue;
+  //   for (let i = 0; i < elements.length; i++) {
+  //     reduced = cb(reduced, elements[i]);
+  //   }
+  // }
+  // return reduced;
+  const newElements = elements.slice();
+  if (startingValue === undefined) {
+    startingValue = newElements.shift();
+  }
+  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.
+  let result;
+  for (let i = 0; i < elements.length; i++) {
+    if (cb(elements[i]) === true) {
+      result = elements[i];
+    } else {
+      result = undefined;
+    }
+  }
+  return result;
 };
 
 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]) === true) {
+      newArr.push(elements[i]);
+    }
+  }
+  return newArr;
 };
 
 /* 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];
+  let outPut = [];
+  each(elements, (num) => {
+    if (Array.isArray(num)) {
+      outPut = outPut.concat(flatten(num));
+    } else {
+      outPut.push(num);
+    }
+  });
+  // for (let i = 0; i < elements.length; i++) {
+  //   for (let j = 0; j < elements[i].length; i++) {
+  //     newArr.push(elements[i][j]);
+  //   }
+  // }
+  return outPut;
 };
-
+// const myArr = [1, [2], [3, [[4]]]];
+// console.log(flatten(myArr));
 /* eslint-enable no-unused-vars, max-len */
 
 module.exports = {
diff --git a/src/callbacks.js b/src/callbacks.js
@@ -7,32 +7,53 @@ const firstItem = (arr, cb) => {
 
 const getLength = (arr, cb) => {
   // getLength passes the length of the array into the callback.
-  cb(arr.length); // do i have ur code ryan ? ahh
+  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.
+  let sum = x + y;
+  cb(sum);
 };
 
 const multiplyNums = (x, y, cb) => {
   // multiplyNums multiplies two numbers and passes the result to the callback.
+  let prod = x * y;
+  cb(prod);
 };
 
 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 (list[i] === item){
+      cb(true)
+    } else {
+      cb(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.
+  // [2,3,5,2,5,7]
+  let obj = {};
+  let resultArr = [];
+  for (let i = 0; i < array.length; i++){
+    if (!(array[i] in obj)) {
+      resultArr.push(array[i])
+      obj[array[i]] = true;
+    }
+  }
+   cb(resultArr);
 };
 
 /* eslint-enable */
diff --git a/src/closure.js b/src/closure.js
@@ -5,28 +5,51 @@ const counter = () => {
   // Example: const newCounter = counter();
   // newCounter(); // 1
   // newCounter(); // 2
+  let count = 0;
+  return () => {
+    count++;
+    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 count = 0;
+  return {
+    increment() {
+      return ++count;
+    },
+    decrement() {
+      return --count;
+    },
+  };
 };
-
 const limitFunctionCallCount = (cb, n) => {
   // Should return a function that invokes `cb`.
   // The returned function should only allow `cb` to be invoked `n` times.
+  let count = 0;
+  return (...args) => {
+    if (count >= n) {
+      return null;
+    }++count;
+    return cb(...args);
+  };
 };
-
 /* STRETCH PROBLEM */
 
 const cacheFunction = (cb) => {
-  // Should return a funciton that invokes `cb`.
-  // 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
-  // then it should return the cached result and not invoke `cb` again.
-  // `cb` should only ever be invoked once for a given set of arguments.
+  const cacheObj = {};
+  return (...args) => {
+    const key = args;
+    if (!(key in cacheObj)) {
+      const newVal = cb(...args);
+      cacheObj[key] = newVal;
+      return newVal;
+    }
+    return cacheObj.key;
+  };
 };
 
 /* eslint-enable no-unused-vars */
@@ -37,3 +60,12 @@ module.exports = {
   cacheFunction,
   limitFunctionCallCount,
 };
+
+// const hi = 'hello';
+// const say = () => {
+//   console.log(hi);
+// };
+// const dosome = () => {
+//   say();
+// };
+// dosome();
diff --git a/src/objects.js b/src/objects.js
@@ -5,22 +5,38 @@ 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 result = {};
+  const objKeys = Object.keys(obj);
+  const objValues = Object.values(obj);
+  for (let i = 0; i < objValues.length; i++) {
+    result[objKeys[i]] = cb(objValues[i]);
+  }
+  return result;
 };
 
 const pairs = (obj) => {
   // Convert an object into a list of [key, value] pairs.
   // http://underscorejs.org/#pairs
+  const pairsArr = [];
+  const objkeys = Object.keys(obj);
+  const objValues = Object.values(obj);
+  for (let i = 0; i < objkeys.length; i++) {
+    pairsArr.push([objkeys[i], objValues[i]]);
+  }
+  return pairsArr;
 };
 
 /* STRETCH PROBLEMS */
@@ -29,14 +45,28 @@ 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 result = {};
+  const objKeys = Object.keys(obj);
+  const objValues = Object.values(obj);
+  for (let i = 0; i < objKeys.length; i++) {
+    result[objValues[i]] = objKeys[i];
+  }
+  return result;
 };
 
 const defaults = (obj, defaultProps) => {
   // Fill in undefined properties that match properties on the `defaultProps` parameter object.
   // Return `obj`.
   // http://underscorejs.org/#defaults
+  const defaultKeys = Object.keys(defaultProps);
+  const defaultValues = Object.values(defaultProps);
+  for (let i = 0; i < defaultKeys.length; i++) {
+    if (!(defaultKeys[i] in obj)) {
+      obj[defaultKeys[i]] = defaultValues[i];
+    }
+  }
+  return obj;
 };
-
 /* eslint-enable no-unused-vars */
 
 module.exports = {
