Jean S Ariza

assignments/arrays.js

@@ -1,4 +1,9 @@
+'use strict';
 const items = [1, 2, 3, 4, 5, 5]; // use this array to test your code. 
+
+let cb = () => "";
+cb = ( x ) => x;
+
 /*
   Complete the following functions.
   These functions only need to work with arrays.
@@ -9,46 +14,112 @@ const items = [1, 2, 3, 4, 5, 5]; // use this array to test your code.
   You CAN use concat, push, pop, etc. but do not use the exact method that you are replicating
 */
 
+
+cb = ( x ) => console.log(x-1);
 function each(elements, cb) {
   // Do NOT use forEach to complete this function.
   // 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
+  for ( let value of  elements ) {
+    cb( value );
+  }
 }
+each(items, cb);
+
 
+cb = ( x ) => x*2;
 function map(elements, cb) {
   // Do NOT use .map, to complete this function.
   // How map works: Map calls a provided callback function once for each element in an array, in order, and functionructs a new array from the res .
   // Produces a new array of values by mapping each value in list through a transformation function (iteratee).
   // Return the new array.
+  let returnArray = [];
+  for ( let value of elements ){
+    returnArray.push(cb(value));
+  }
+  return returnArray;
 }
+// console.log(map(items, cb));
 
+
+cb = ( reduced, value ) => reduced += value;
 function reduce(elements, cb, startingValue) {
   // Do NOT use .reduce to complete this function.
   // How reduce works: A reduce function combines 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 index = startingValue || 0;
+  const control = elements[index];
+  let reduced = control;
+  for ( let i = index+1; i < elements.length; ++i ) {
+    reduced = cb(reduced, elements[i] )
+  }
+  return reduced;
 }
+// console.log(reduce(items, cb));
+
 
+cb = ( x ) => x === "valueToCompare" ? true : false;
 function 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.
+  let found = undefined;
+  for ( let i = 0; i < elements.length; ++i) {
+    if ( cb(elements[i]) ) { return found = elements[i] }
+  }
+  return found;
 }
+let something = [undefined, null,"a"];
+// console.log(find(items, cb));
+// console.log(find(something, cb));
+
 
+cb = ( x ) => x === "anyFilter" ? true : false;
 function 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
+  let filtered =[];
+  for ( let value of elements ){
+    cb(value) ? filtered.push(value) : null;
+  }
+  return filtered;
 }
 
+
 const nestedArray = [1, [2], [[3]], [[[4]]]]; // use this to test 'flatten'
+const nestedArray2 = [[[[4]]],5, [2], [[3]], [[[4]]]]; // use this to test 'flatten'
+const nestedArray3 = [[[[]]],,[], [[]], [[[]]]]; // use this to test 'flatten'
 
 function flatten(elements) {
   // Flattens a nested array (the nesting can be to any depth).
   // Hint: You can solve this using recursion.
   // Example: flatten([1, [2], [3, [[4]]]]); => [1, 2, 3, 4];
+  let toFlat = [];
+
+  function removeArray ( item ) {
+    Array.isArray( item ) ? checkItems(item) : toFlat.push(item); //?
+  }
+
+  function checkItems ( array ) {
+    for ( let item of array ) {
+      console.log(item);
+      removeArray( item );
+    }
+  }
+
+  checkItems(elements);
+  return toFlat;
+
+
 }
+
+console.log(flatten(nestedArray));
+console.log(flatten(nestedArray2));
+console.log(flatten(nestedArray3));
+

assignments/closure.js

@@ -1,20 +1,69 @@
+'use strict'
+
 function 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 counter = 0;
+  function increment () {
+    return ++counter;;
+  }
+  function decrement () {
+    return --counter;
+  }
+  return {
+    increment,
+    decrement
+  }
 }
+console.log(counterFactory().increment());
+console.log(counterFactory().decrement());
+
+
 
+function cb () { console.log("Callback invoked") };
 function limitFunctionCallCount(cb, n) {
   // Should return a function that invokes `cb`.
   // The returned function should only allow `cb` to be invoked `n` times.
   // Returning null is acceptable if cb can't be returned
+  let counter = n;
+  function invoke () {
+  //  counter-- >  0 ? cb() : throw(new Error (`Callback already called ${n}-times`));  I CAN NOT FIGURE OUT WHY THIS LINE IS NO WORKING
+   counter-- >  0 ? cb() : console.log(`Callback already called ${n}-times`);
+  }
+  return {invoke};
 }
+let nTimes = limitFunctionCallCount(cb, 3);
+nTimes.invoke();
+nTimes.invoke();
+nTimes.invoke();
+nTimes.invoke();
 
+
+cb = x => `Good! argument ${x} was no used!`
+// console.log(cb(1));
 function 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 cache = new Set();
+
+  function invoke ( param ) {
+    if (!cache.has(param)) {
+      console.log(cache);
+      cache.add(param);
+      return cb(param);
+    } 
+    else {
+      console.log(cache);
+      return cache;
+    }
+  } 
+  return {invoke};
 }
+let argumentUsed = cacheFunction(cb);
+console.log(argumentUsed.invoke("x"));
+console.log(argumentUsed.invoke("x"));

assignments/objects.js

@@ -1,37 +1,72 @@
 const testObject = { name: 'Bruce Wayne', age: 36, location: 'Gotham' }; // use this object to test your functions
-
+let cb = x => x;
 // Complete the following underscore functions.
 // Reference http://underscorejs.org/ for examples.
 
 function 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);
 }
+console.log(keys(testObject));
+
 
 function values(obj) {
   // Return all of the values of the object's own properties.
   // Ignore functions
   // http://underscorejs.org/#values
+  const values = [];
+  for ( let prop in obj ) {
+    (typeof obj[prop] === "function") ? null : values.push(obj[prop])
+  }
+  return values;
 }
+console.log(values(testObject));
+
 
+cb = x => "maped: "+x;
 function mapObject(obj, cb) {
   // Like map for arrays, but for objects. Transform the value of each property in turn by passing it to the callback function.
   // http://underscorejs.org/#mapObject
+  const mapped = {}
+  for ( let prop in obj ){
+    mapped[prop] = cb(obj[prop]);
+  }
+  return mapped;
 }
+console.log(mapObject(testObject, cb));
+
+
 
 function pairs(obj) {
   // Convert an object into a list of [key, value] pairs.
   // http://underscorejs.org/#pairs
+
+  /* Seems that Object.entries() is not supported in my editor, but is supported in Chrome Developer Tools */
+  return Object.entries(obj);
 }
+console.log(pairs(testObject));
+
+
 
 /* STRETCH PROBLEMS */
 
 function 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 key = Object.keys(obj);
+  /* Seems that Object.values() is not supported in my editor, but is supported in Chrome Developer Tools */
+  const values = Object.values(obj);
+  const inverted = []
+  for ( let i = 0; i < key.length; i++) {
+    inverted[i] = [values[i],key[i]];
+  };
+  return inverted;
 }
+console.log(invert(testObject));
+
 
 function defaults(obj, defaultProps) {
   // Fill in undefined properties that match properties on the `defaultProps` parameter object.