all tests passed

src/1-multiplication.js

@@ -1,3 +1,3 @@
 export const multiply = (a, b) => {
-  a * b
+  return a * b
 }

src/2-first-last.js

@@ -1,3 +1,11 @@
 export const firstLast = (items) => {
-  return `First: ${items[0]}, Last: ${items[1]}`
+  if (!items.length){
+    return `No items!`
+  }
+  else if (items.length === 1){
+    return `Only item: ${items[0]}`
+  }
+  else{
+    return `First: ${items[0]}, Last: ${items[items.length-1]}`
+  }
 }

src/3-find-index.js

@@ -1,3 +1,3 @@
 export const findIndex = (array, value) => {
-  return
+  return array.indexOf(value)
 }

src/4-angle-calculator.js

@@ -1,3 +1,3 @@
 export const angleCalculator = (turns) => {
-  return
+  return (turns * 360) 
 }

src/5-month-name.js

@@ -4,5 +4,10 @@ const months = [
 ]
 
 export const monthName = (monthNumber) => {
-  return months[monthNumber]
+  if(monthNumber >= 1 && monthNumber <= 12){
+    return months[monthNumber-1]
+  }
+  else{
+    return null
+  }
 }

src/6-filter-numbers.js

@@ -1,3 +1,3 @@
 export const filterNumbers = (array, largerThan) => {
-  return array
+  return array.filter(item => item <= largerThan)
 }

src/7-is-empty.js

@@ -1,9 +1,16 @@
 export const isEmpty = (stringArrayOrObject) => {
   const type = typeof stringArrayOrObject
 
-  if (type === 'string') {
-    return stringArrayOrObject === ''
+  if (type === 'string' && stringArrayOrObject.length){
+      return false
+    }
+  else if (Object.prototype.toString.call(stringArrayOrObject) === '[object Array]' && stringArrayOrObject.length){
+    return false
+  }
+  else if (Object.prototype.toString.call(stringArrayOrObject) === '[object Object]' && Object.keys(stringArrayOrObject).length){
+    return false
+  }
+  else{
+    return true
   }
-
-  return false
 }

src/8-hacker-speak.js

@@ -1,3 +1,5 @@
 export const hackerSpeak = (words) => {
-  return words
+  return words.replaceAll("a", "4").replaceAll("e", "3", true).replaceAll("i", "1", true)
+  .replaceAll("o", "0", true).replaceAll("s", "5", true).replaceAll("A", "4").replaceAll("E", "3", true).replaceAll("I", "1", true)
+  .replaceAll("O", "0", true).replaceAll("S", "5", true)
 }

src/9-hashtags.js

@@ -1,3 +1,10 @@
 export const hashtags = (text) => {
-  return text
+  let splitArray = text.split(" ")
+  let hastagsArray = []
+  for(let i = 0; i < splitArray.length; i++){
+    if (splitArray[i].charAt(0) === '#'){
+      hastagsArray.push(splitArray[i])
+    }
+  }
+  return(hastagsArray)
 }