typo fixes and some minor corrections

Author: Asabeneh

05_Day_Arrays/05_day_arrays.md

@@ -59,7 +59,7 @@ An array is a collection of different data types which are ordered and changeabl
 ### How to create an empty array
 
 In JavaScript, we can create an array in different ways. Let us see different ways to create an array.
-It is very common to use *const* instead of *let* to declare an array variable. If you ar using const it means you do not use that variable name again.
+It is very common to use _const_ instead of _let_ to declare an array variable. If you ar using const it means you do not use that variable name again.
 
 - Using Array constructor
 
@@ -400,7 +400,7 @@ if(index === -1){
 // we can use also ternary here
 index === -1 ? console.log('This fruit does not exist in the array'): console.log('This fruit does exist in the array')
 
-// let us check if a avocado exist in the array
+// let us check if an avocado exist in the array
 let indexOfAvocado = fruits.indexOf('avocado')  // -1, if the element not found index is -1
 if(indexOfAvocado === -1){
    console.log('This fruit does not exist in the array')  
@@ -521,18 +521,20 @@ Splice: It takes three parameters:Starting position, number of times to be remov
 
 ```js
   const numbers = [1, 2, 3, 4, 5]
-
-  console.log(numbers.splice())                // -> remove all items
+  numbers.splice()
+  console.log(numbers)                // -> remove all items
 
 ```
 
 ```js
   const numbers = [1, 2, 3, 4, 5]
-  console.log(numbers.splice(0,1))            // remove the first item
+	numbers.splice(0,1)
+  console.log(numbers)            // remove the first item
 ```
 
 ```js
-  const numbers = [1, 2, 3, 4, 5, 6];
+  const numbers = [1, 2, 3, 4, 5, 6]
+	numbers.splice(3, 3, 7, 8, 9)
   console.log(numbers.splice(3, 3, 7, 8, 9))  // -> [1, 2, 3, 7, 8, 9] //it removes three item and replace three items
 ```
 
@@ -544,15 +546,13 @@ Push: adding item in the end. To add item to the end of an existing array we use
 // syntax
 const arr  = ['item1', 'item2','item3']
 arr.push('new item')
-
 console.log(arr)
 // ['item1', 'item2','item3','new item']
 ```
 
 ```js
 const numbers = [1, 2, 3, 4, 5]
 numbers.push(6)
-
 console.log(numbers) // -> [1,2,3,4,5,6]
 
 numbers.pop() // -> remove one item from the end
@@ -562,7 +562,6 @@ console.log(numbers) // -> [1,2,3,4,5]
 ```js
 let fruits = ['banana', 'orange', 'mango', 'lemon']
 fruits.push('apple')
-
 console.log(fruits)    // ['banana', 'orange', 'mango', 'lemon', 'apple']
 
 fruits.push('lime')
@@ -576,7 +575,6 @@ pop: Removing item in the end.
 ```js
 const numbers = [1, 2, 3, 4, 5]
 numbers.pop() // -> remove one item from the end
-
 console.log(numbers) // -> [1,2,3,4]
 ```
 
@@ -587,7 +585,6 @@ shift: Removing one array element in the beginning of the array.
 ```js
 const numbers = [1, 2, 3, 4, 5]
 numbers.shift() // -> remove one item from the beginning
-
 console.log(numbers) // -> [2,3,4,5]
 ```
 
@@ -598,7 +595,6 @@ unshift: Adding array element in the beginning of the array.
 ```js
 const numbers = [1, 2, 3, 4, 5]
 numbers.unshift(0) // -> add one item from the beginning
-
 console.log(numbers) // -> [0,1,2,3,4,5]
 ```
 
@@ -609,7 +605,6 @@ reverse: reverse the order of an array.
 ```js
 const numbers = [1, 2, 3, 4, 5]
 numbers.reverse() // -> reverse array order
-
 console.log(numbers) // [5, 4, 3, 2, 1]
 
 numbers.reverse()
@@ -769,7 +764,7 @@ const webTechs = [
     - Find the median age(one middle item or two middle items divided by two)
     - Find the average age(all items divided by number of items)
     - Find the range of the ages(max minus min)
-    - Compare the value of (min - average) and (max - average), use *abs()* method
+    - Compare the value of (min - average) and (max - average), use _abs()_ method
 1.Slice the first ten countries from the [countries array](https://github.com/Asabeneh/30DaysOfJavaScript/tree/master/data/countries.js)
 1. Find the middle country(ies) in the [countries array](https://github.com/Asabeneh/30DaysOfJavaScript/tree/master/data/countries.js)
 2. Divide the countries array into two equal arrays if it is even.  If countries array is not even , one more country for the first half.

07_Day_Functions/07_day_functions.md

@@ -273,7 +273,7 @@ const sumAllNums = (...args) => {
   console.log(args)
 }
 
-sumAllNums(1, 2, 3, 4))
+sumAllNums(1, 2, 3, 4)
 // [1, 2, 3, 4]
 
 ```

08_Day_Objects/08_day_objects.md

@@ -391,7 +391,7 @@ _Object.keys_: To get the keys or properties of an object as an array
 
 ```js
 const keys = Object.keys(copyPerson)
-console.log(keys) //['name', 'age', 'country', 'skills', 'address', 'getPersonInfo']
+console.log(keys) //['firstName', 'age', 'country','city', 'skills','title', 'address', 'getPersonInfo']
 const address = Object.keys(copyPerson.address)
 console.log(address) //['street', 'pobox', 'city']
 ```

09_Day_Higher_order_functions/09_day_higher_order_functions.md

@@ -88,7 +88,7 @@ console.log(higherOrder(2)(3)(10))
 Let us see were we use call back functions. For instance the _forEach_ method uses call back.
 
 ```js
-const numbers = [1, 2, 3, 4]
+const numbers = [1, 2, 3, 4, 5]
 const sumArray = arr => {
   let sum = 0
   const callback = function(element) {
@@ -518,7 +518,7 @@ console.log(numbers) //[100, 37, 9.81, 3.14]
 
 #### Sorting Object Arrays
 
-When ever we sort objects in an array. We use the object key to compare. Lets see the example below.
+Whenever we sort objects in an array, we use the object key to compare. Let us see the example below.
 
 ```js
 objArr.sort(function (a, b) {
@@ -538,7 +538,7 @@ objArr.sort(function (a, b) {
 const users = [
   { name: 'Asabeneh', age: 150 },
   { name: 'Brook', age: 50 },
-  { name: 'Eyo', age: 100 },
+  { name: 'Eyob', age: 100 },
   { name: 'Elias', age: 22 },
 ]
 users.sort((a, b) => {

10_Day_Sets_and_Maps/10_day_Sets_and_Maps.md

@@ -45,7 +45,7 @@
 ## Set
 
 Set is  a collection of elements. Set can only contains unique elements.
-Lets see how to create a set
+Let us see how to create a set in the section below.
 
 ### Creating an empty set
 
@@ -55,7 +55,7 @@ console.log(companies)
 ```
 
 ```sh
-{}
+Set(0) {}
 ```
 
 ### Creating set from array
@@ -117,7 +117,6 @@ companies.add('Facebook')
 companies.add('Amazon')
 companies.add('Oracle')
 companies.add('Microsoft')
-
 console.log(companies.size) // 5 elements in the set
 console.log(companies)
 ```
@@ -165,13 +164,11 @@ It removes all the elements from a set.
 
 ```js
 companies.clear()
-
 console.log(companies)
 ```
 
 ```sh
-{}
-
+Set(0) {}
 ```
 
 See the example below to learn how to use set.
@@ -202,7 +199,7 @@ console.log(counts)
 ```
 
 ```js
-;[
+[
   { lang: 'English', count: 3 },
   { lang: 'Finnish', count: 1 },
   { lang: 'French', count: 2 },
@@ -345,7 +342,7 @@ Helsinki
 
 ### Checking key in Map
 
-Check if a key exist in a map using _has_ method. It returns _true_ or _false_.
+Check if a key exists in a map using _has_ method. It returns _true_ or _false_.
 
 ```js
 console.log(countriesMap.has('Finland'))
@@ -371,7 +368,7 @@ for (const country of countriesMap) {
 
 ```js
 for (const [country, city] of countriesMap){
-console.log(country, city)
+ console.log(country, city)
 }
 ```
 
@@ -438,8 +435,6 @@ const countries = ['Finland', 'Sweden', 'Norway']
   ]
 ```
 
-
 🎉 CONGRATULATIONS ! 🎉
 
-
 [<< Day 9](../09_Day_Higher_order_functions/09_day_higher_order_functions.md) | [Day 11 >>](../11_Day_Destructuring_and_spreading/11_day_destructuring_and_spreading.md)

11_Day_Destructuring_and_spreading/11_day_destructuring_and_spreading.md

@@ -18,23 +18,23 @@
 ![Day 11](../images/banners/day_1_11.png)
 
 - [Day 11](#day-11)
-  - [Destructuring and Spread](#destructuring-and-spread)
-    - [Destructing Arrays](#destructing-arrays)
-    - [Destructuring during iteration](#destructuring-during-iteration)
-    - [Destructuring Object](#destructuring-object)
-    - [Renaming during structuring](#renaming-during-structuring)
-    - [Object parameter without destructuring](#object-parameter-without-destructuring)
-    - [Object parameter with destructuring](#object-parameter-with-destructuring)
-    - [Destructuring object during iteration](#destructuring-object-during-iteration)
-    - [Spread or Rest Operator](#spread-or-rest-operator)
-    - [Spread operator to get the rest of array elements](#spread-operator-to-get-the-rest-of-array-elements)
-    - [Spread operator to copy array](#spread-operator-to-copy-array)
-    - [Spread operator to copy object](#spread-operator-to-copy-object)
-      - [Spread operator with arrow function](#spread-operator-with-arrow-function)
-  - [Exercises](#exercises)
-    - [Exercises: Level 1](#exercises-level-1)
-    - [Exercises: Level 2](#exercises-level-2)
-    - [Exercises: Level 3](#exercises-level-3)
+	- [Destructuring and Spread](#destructuring-and-spread)
+		- [Destructing Arrays](#destructing-arrays)
+		- [Destructuring during iteration](#destructuring-during-iteration)
+		- [Destructuring Object](#destructuring-object)
+		- [Renaming during structuring](#renaming-during-structuring)
+		- [Object parameter without destructuring](#object-parameter-without-destructuring)
+		- [Object parameter with destructuring](#object-parameter-with-destructuring)
+		- [Destructuring object during iteration](#destructuring-object-during-iteration)
+		- [Spread or Rest Operator](#spread-or-rest-operator)
+		- [Spread operator to get the rest of array elements](#spread-operator-to-get-the-rest-of-array-elements)
+		- [Spread operator to copy array](#spread-operator-to-copy-array)
+		- [Spread operator to copy object](#spread-operator-to-copy-object)
+			- [Spread operator with arrow function](#spread-operator-with-arrow-function)
+	- [Exercises](#exercises)
+		- [Exercises: Level 1](#exercises-level-1)
+		- [Exercises: Level 2](#exercises-level-2)
+		- [Exercises: Level 3](#exercises-level-3)
 
 # Day 11
 
@@ -108,7 +108,7 @@ If we like to skip on of the values in the array we use additional comma. The co
 
 ```js
   const names = ['Asabeneh', 'Brook', 'David', 'John']
-  let [, secondPerson, , fourthPerson] = name // first and third person is omitted
+  let [, secondPerson, , fourthPerson] = names // first and third person is omitted
 
   console.log(secondPerson, fourthPerson)
 ```
@@ -218,7 +218,7 @@ console.log(w, h, a, p)
 20 10 200 undefined
 ```
 
-If the key is not found in the object the variable will be assigned to undefined. In case, the key is not in the object we can give a default value during declaration. See the example.
+If the key is not found in the object the variable will be assigned to undefined. Sometimes the key might not be in the object, in that case we can give a default value during declaration. See the example.
 
 ```js
 const rectangle = {
@@ -229,7 +229,7 @@ const rectangle = {
 let { width, height, area, perimeter = 60 } = rectangle
 
 console.log(width, height, area, perimeter) //20 10 200 60
-//Lets modify the object:width to 30 and perimeter to 80
+//Let us modify the object:width to 30 and perimeter to 80
 ```
 
 ```js
@@ -243,7 +243,7 @@ let { width, height, area, perimeter = 60 } = rectangle
 console.log(width, height, area, perimeter) //30 10 200 80
 ```
 
-Destructuring keys as a function parameters. Lets create a function which take a rectangle object and it return a perimeter of a rectangle.
+Destructuring keys as a function parameters. Let us create a function which takes a rectangle object and it returns a perimeter of a rectangle.
 
 ### Object parameter without destructuring
 
@@ -282,7 +282,7 @@ const person = {
   ],
   languages: ['Amharic', 'English', 'Suomi(Finnish)']
 }
-// Lets create a function which give information about the person object without destructuring
+// Let us create a function which give information about the person object without destructuring
 
 const getPersonInfo = obj => {
   const skills = obj.skills
@@ -314,7 +314,7 @@ console.log(calculatePerimeter(rect)) // 60
 ```
 
 ```js
-// Lets create a function which give information about the person object with destructuring
+// Let us create a function which give information about the person object with destructuring
 const getPersonInfo = ({
   firstName,
   lastName,
@@ -335,7 +335,7 @@ const getPersonInfo = ({
 }
 console.log(getPersonInfo(person))
 /*
-Asabeneh Yetayeh lives in Finland. He is  200 years old. He is an Instructor and Developer. He teaches HTML, CSS, JavaScript, React, Redux, Node, MongoDB, Python and D3.js. He speaks Amharic, English and a little bit of Suomi(Finnish)
+Asabeneh Yetayeh lives in Finland. He is  250 years old. He is an Instructor and Developer. He teaches HTML, CSS, JavaScript, React, Redux, Node, MongoDB, Python and D3.js. He speaks Amharic, English and a little bit of Suomi(Finnish)
 */
 ```
 
@@ -373,7 +373,7 @@ Assess Test Result 4/1/2020 1:00 false
 
 ### Spread or Rest Operator
 
-When we destructure an array we use the spread operator(...) to get the rest elements as array. In addition to that we use spread operator to spread arr elements to another array.
+When we destructure an array we use the spread operator(...) to get the rest elements as array. In addition to that we use spread operator to spread array elements to another array.
 
 ### Spread operator to get the rest of array elements
 
@@ -499,7 +499,7 @@ const sumAllNums = (...args) => {
   console.log(args)
 }
 
-sumAllNums(1, 2, 3,4,5)
+sumAllNums(1, 2, 3, 4, 5)
 
 ```
 
@@ -519,7 +519,7 @@ const sumAllNums = (...args) => {
 
 }
 
-console.log(sumAllNums(1, 2, 3,4,5))
+console.log(sumAllNums(1, 2, 3, 4, 5))
 ```
 
 ```sh
@@ -597,7 +597,6 @@ const users = [
 1. Iterate through the users array and get all the keys of the object using destructuring
 2. Find the persons who have less than two skills
 
-
 ### Exercises: Level 3
 
 1. Destructure the countries object print name, capital, population and languages of all countries
@@ -613,7 +612,7 @@ const users = [
   ```
 
 3. Write a function called *convertArrayToObject* which can convert the array to a structure object.
-   
+
   ```js
       const students = [
           ['David', ['HTM', 'CSS', 'JS', 'React'], [98, 85, 90, 95]],
@@ -693,6 +692,7 @@ const users = [
   }
 
 ```
+
 🎉 CONGRATULATIONS ! 🎉
 
-[<< Day 10](../10_Day_Sets_and_Maps/10_day_Sets_and_Maps.md) | [Day 12 >>](../12_Day_Regular_expressions/12_day_regular_expressions.md)
+[<< Day 10](../10_Day_Sets_and_Maps/10_day_Sets_and_Maps.md) | [Day 12 >>](../12_Day_Regular_expressions/12_day_regular_expressions.md)