Add solutions for challenges josedlujan#1, josedlujan#2, and josedlujan#3

Author: KhadidjaArezki

Community_Github_Challenges_1/highestDigit.js

@@ -0,0 +1,23 @@
+/**
+ * highestDigit:
+ * @param num: Number
+ * @return   : Number (single digit)
+ * @example  : highestDigit(12899) -> 9
+ * 
+ * Receives a number as an argument.
+ * Returns the highest digit in that number.
+ */
+function highestDigit(num) {
+  // return Math.max(...num.toString()) -- shorter solution that I don't prefer 
+  return Array.prototype.reduce.call(
+    num.toString(),
+    (max, digit) => {
+      return digit > max ? digit : max
+    }
+  )
+}
+
+console.log(highestDigit(12899))
+console.log(highestDigit(8123))
+console.log(highestDigit(193))
+console.log(highestDigit(1))

Community_Github_Challenges_1/match.js

@@ -0,0 +1,17 @@
+/**
+ * match:
+ * @param str1: String
+ * @param str2: String
+ * @return    : Boolean
+ * @example   : match("Jose", "JoSe") -> true
+ * 
+ * Validates whether the two strings are identical.
+ */
+function match(str1, str2) {
+    return str1.toLowerCase() === str2.toLowerCase()
+}
+
+console.log(match("Jose", "JoSe"))
+console.log(match("water", "wait"))
+console.log(match("JOHN", "JOHn"))
+console.log(match("ElEmEnTs", "eLeMeNtS"))

Community_Github_Challenges_2/generatort.js

@@ -0,0 +1,21 @@
+/**
+ * generatort:
+ * @param n: Number(optional, defaults to 5)
+ * @yield  : n numbers
+ * @return : undefined
+ * @example: generatort(2) -> 130,38
+ * @example: generatort() -> 0,29,82,1,39
+ * 
+ * Recursive generator function.
+ * Generates n random numbers in the range (1 - 100)
+ * If n is not provided, it genetates 5 random numbers.
+ */
+function* generatort(n=5) {
+  if (n === 0) return
+  yield Math.floor(Math.random(100)*100)
+  yield* generatort(n-1)
+}
+
+for (const random of generatort()) {
+  console.log(random)
+}

Community_Github_Challenges_2/rangeEvens.js

@@ -0,0 +1,40 @@
+/********************** Helper Functions *********************/
+/**
+ * arrayFromRange:
+ * @param lowEnd : Number
+ * @param highEnd: Number
+ * @return       : Array of Numbers
+ * @example      : arrayFromRange(34, 39) -> [34, 35, 36, 37, 38, 39]
+
+ * Returns an array of numbers from a range.
+ * The range is represented by the two arguments.
+ */
+function arrayFromRange(lowEnd, highEnd) {
+  return Array.from(
+    {
+      length: (highEnd - lowEnd) + 1
+    },
+    (_, i) => lowEnd + i
+  )
+}
+/*************************************************************/
+
+/**
+ * rangeEvens:
+ * @param lowEnd : Number
+ * @param highEnd: Number
+ * @return       : Array (of numbers)
+ * @example      : rangeEvens(10,20) -> 10,12,14,16,18
+ * 
+ * Assumes that lowEnd is a positive integer greater than 0.
+ * Checks that highEnd is positive integer greater that lowEnd.
+ * Returns all even numbers within the range of lowEnd and highEnd.
+ */
+function rangeEvens(lowEnd, highEnd) {
+  if (lowEnd > highEnd) return []
+  return arrayFromRange(lowEnd, highEnd)
+    .filter(num => num % 2 == 0)
+}
+
+console.log(rangeEvens(10, 20))
+console.log(rangeEvens(57, 80))

Community_Github_Challenges_3/README.md

@@ -28,7 +28,7 @@ The function must return the sum of all positive even numbers in the list.
 ### Example
 - sum(1,2,3,4,5,6,7,8,9,10,12) = 42
 - sum(2,2,2,5,4,2) = 12
-- sum(2,1,3,5,6,10) = 12
+- sum(2,1,3,5,6,10) = 18
 
 #### Notes
 - No notes

Community_Github_Challenges_3/leftKeys.js

@@ -0,0 +1,37 @@
+/**
+ * Map.prototype.filter:
+ * @param   {Function} predicate 
+ * @returns {Map}
+ * @example new Map([['a', 1], ['b', 2]]).filter((key, value) => value === 1) -> Map { 'a' => 1 }
+ * 
+ * Applies the predicate function to each entry of the map.
+ * Returns a map with entries for which the predicate function returns true.
+ */
+Map.prototype.filter = function(predicate) {
+  const results = new Map()
+
+  this.forEach((value, key) => {
+    if (predicate(key, value, map=this)) {
+      results.set(key, value)
+    }
+  })
+
+  return results
+}
+
+/**
+ * leftKeys:
+ * @param   {Map} map1
+ * @param   {Map} map2
+ * @return  {Map}
+ * @example leftKeys({'a':1,'b':2,'c':3},{'a':1,'b':2,'d':9}) -> Map { 'c' => 3 }
+ * 
+ * Returns a map of all the keys of map1 that are not found in map2.
+ */
+function leftKeys(map1, map2) {
+  return map1.filter((key, _) => !map2.has(key))
+}
+
+const map1 = new Map([['a', 1], ['b', 2], ['c', 3]])
+const map2 = new Map([['a', 1], ['b', 2], ['d', 9]])
+console.log(leftKeys(map1, map2))

Community_Github_Challenges_3/sumEvens.js

@@ -0,0 +1,17 @@
+/**
+ * SumEvens:
+ * @param   {Array} numArray
+ * @return  {Number}
+ * @example sumEvens([2,1,3,5,6,10]) = 18
+ * 
+ * Returns the sum of all positive even numbers in the list.
+ */
+function sumEvens(numArray) {
+  return numArray.reduce((sum, num) => {
+    return num % 2 === 0 && num > 0 ? sum + num : sum
+  }, 0)
+}
+
+console.log(sumEvens([2,1,3,5,6,10]))
+console.log(sumEvens([1,2,3,4,5,6,7,8,9,10,12]))
+console.log(sumEvens([2,2,2,5,4,2]))