forEach and Map

Author: suhailroushan13

.gitignore

@@ -1,15 +1,6 @@
 var priceList = [1, 2, 3, 4, 5, 6, 7, 8, 9];
 
 function find(arr, num) {
-  let news;
-  for (let i = 0; i <= arr.length - 1; i++) {
-    news = new Array(arr).flat();
-
-    console.log(news[i]);
-
- 
-   
-
-  }
+  arr.includes(num) ? console.log("Hau") : console.log("No");
 }
-find(priceList, 10);
+find(priceList, 1);

1. Intro to JavaScript/1.js

@@ -0,0 +1,10 @@
+var priceList = [1, 2, 3, 4, 5, 6, 7, 8, 9];
+
+function find(arr, num) {
+  if (arr.includes(num)) {
+    console.log("Hau Hai");
+  } else {
+    console.log("No Bro");
+  }
+}
+find(priceList, 19);

2. Basic of JavaScript/1-12/1.js

@@ -0,0 +1,19 @@
+// Indexof Array Method
+
+// Array Indexof gives the index of the specifc element from
+// the array
+
+// IF THERE IS NO INDEX OF THAT ELEMENT IF GIVE RETURN -1
+
+const arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
+
+console.log(arr.indexOf(1)); // 0
+console.log(arr.indexOf(2)); // 1
+console.log(arr.indexOf(10)); // 9
+
+const words = ["Java", "C", "C++", "Python"];
+// Indexs are   0       1     2       3
+
+console.log(words.indexOf("Java")); // 0
+console.log(words.indexOf("C++")); 2
+console.log(words.indexOf("JavaScript")); // -1

2. Basic of JavaScript/1-12/10.js

@@ -0,0 +1,11 @@
+const arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
+
+const search = (arr, num) => {
+  if (arr.indexOf(num) == -1) {
+    console.log("Unavaliable");
+  } else {
+    console.log("Hau hai re bhai");
+  }
+};
+
+search(arr,10)

2. Basic of JavaScript/1-12/11.js

@@ -0,0 +1,21 @@
+// Array is.Array() //
+// Checks the array is a array or not
+
+// Returns true if the array is true
+// Returns false if the array is false
+
+const arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
+
+console.log(arr);
+
+console.log(Array.isArray(arr));
+
+//
+
+const arr2 = new Array(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
+console.log(arr2);
+
+console.log(Array.isArray(arr2));
+
+console.log(typeof arr2); // Its an Object but shows as Array
+

2. Basic of JavaScript/1-12/12.js

@@ -0,0 +1,20 @@
+const arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
+
+const arr2 = arr;
+
+console.log(arr2 === arr);
+
+const s = "Hello";
+const j = s;
+console.log(j === s);
+
+const a = { name: "Suhail" };
+const b = a;
+console.log(a === b);
+
+const arr3 = new Array(1, 2, 3, 4, 4, 5);
+console.log((arr == arr3));
+console.log(typeof arr);
+console.log(typeof arr3);
+
+

2. Basic of JavaScript/1-12/2.js

@@ -0,0 +1,15 @@
+// passing an empty array []
+console.log(Array.isArray([])); // true
+
+// we have created an array with element 7 and
+// passed that value to isArray()
+console.log(Array.isArray(new Array(7))); // true
+
+// passing a boolean value
+console.log(Array.isArray(true)); // false
+
+// passing undefined
+console.log(Array.isArray(undefined)); // false
+
+// not passing any argument in isArray()
+console.log(Array.isArray()); // false

2. Basic of JavaScript/1-12/3.js

@@ -0,0 +1,27 @@
+// Array Join() Method
+// The join() method returns a new string by
+// concatenating all of the elements in an array,
+//  separated by a specified separator.
+
+/*
+The join() method does not change the original array.
+Elements like undefined, null, or empty array have an
+ empty string representation.
+*/
+const arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
+
+console.log(arr.join());
+// 1,2,3,4,5,6,7,8,9,10
+
+console.log(arr.join(""));
+// 12345678910
+
+console.log(arr.join(" | "));
+// 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10;
+
+const arr2 = ["Java", "C", "C++"];
+console.log(arr2.join(" "));
+// Java C C++
+
+console.log(arr.join("+"));
+// 1+2+3+4+5+6+7+8+9+10

2. Basic of JavaScript/1-12/4.js

@@ -0,0 +1,36 @@
+// JavaScript Array keys()
+
+// The keys() method returns a new Array
+// Iterator object that contains the keys
+// for each element in the array.
+
+const arr = ["Java", "C", "C++", "Python", "Javascript"];
+
+let store = arr.keys();
+
+// for (let i of store) {
+//   console.log(i);
+// }
+// It Also gives keys for empty array to
+const arr2 = [
+  { name: "Rahul", score: 89 }, // 0
+  { name: "Vivek", score: 88 }, // 1
+  ,                             // 2
+  { name: "Sourav", score: 82 },// 3
+  { name: "Gautam", score: 91 },// 4
+  { name: "Sunil", score: 79 }, // 5
+];
+
+let store2 = arr2.keys();
+
+for (let j of store2) {
+  console.log(j);
+}
+/*
+0
+1
+2
+3
+4
+5
+*/

2. Basic of JavaScript/1-12/5.js

@@ -0,0 +1,18 @@
+// Array lastindexof()
+// The lastIndexOf() method returns the index of the last
+//  occurrence of a specified element in the array.
+
+// Example;
+const arr = ["s", "u", "h", "a", "i", "l", "r", "o", "n", "s", "h", "a", "n"];
+
+//  Couting Index starts from 1 to 12 from left to right
+// But Finding element starts from right to left
+console.log(arr.lastIndexOf("n")); //12
+console.log(arr.lastIndexOf("a")); // 11
+
+// It accepts 2 parameters
+
+// arr.lastindexof(ele,startfromindex)
+//  fromIndex starts from 1
+
+

2. Basic of JavaScript/1-12/6.js

@@ -0,0 +1,45 @@
+// Array Length()
+// .length gives the count of array which starts from 1
+const arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
+console.log(arr.length); //10;
+
+arr.length = 4;
+console.log(arr); // [ 1, 2, 3, 4 ]
+arr.length = 8;
+console.log(arr); // [ 1, 2, 3, 4, <4 empty items> ]
+
+const arr2 = [];
+console.log(arr2.length);
+
+var companyList = ["Apple", "Google", "Facebook", "Amazon"];
+console.log(companyList.length); // Output: 4
+
+var randomList = ["JavaScript", 44];
+console.log(randomList.length); // Output: 2
+
+var emptyArray = [];
+console.log(emptyArray.length); // Output: 0
+
+// Example 2: Using Array length in for loop
+var languages = ["JavaScript", "Python", "C++", "Java", "Lua"];
+
+// languages.length can be used to find out
+// the number of times to loop over an array
+for (let i = 0; i < languages.length; i++) {
+  console.log(languages[i]);
+}
+
+// Example 3: Changing length property of Array
+var languages = ["JavaScript", "Python", "C++", "Java", "Lua"];
+
+// truncate the Array to 3 elements
+languages.length = 3;
+
+// Output: [ 'JavaScript', 'Python', 'C++' ]
+console.log(languages);
+
+// extend the Array to length 6
+languages.length = 6;
+
+// Output: [ 'JavaScript', 'Python', 'C++', <3 empty items> ]
+console.log(languages);

2. Basic of JavaScript/1-12/7.js

@@ -0,0 +1,85 @@
+// Difference Between forEach() and Map()
+
+// https://suhailroushan.medium.com/every-developer-should-know-foreach-vs-map-in-javascript-6a55df54c06a
+// 
+console.log("Difference Between forEach() and Map()");
+
+const arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
+
+// 1st Difference
+/*
+The method’s return
+As you can already see, one of 
+the main differences between forEach and map in
+ Javascript is the return of each method.
+
+The forEach() method returns undefined,
+ while map() returns a new array with the 
+ transformed elements.
+ */
+// let newArray = arr.forEach((x) => x * x);
+// console.log(newArray);
+// let newArray1 = arr.map((x) => x * x);
+// console.log(newArray1);
+// console.log(arr.forEach((element) => element * element));
+// console.log(arr.map((element) => element * element));
+/*
+undefined
+[
+   1,  4,  9, 16,  25,
+  36, 49, 64, 81, 100
+]
+undefined
+[
+   1,  4,  9, 16,  25,
+  36, 49, 64, 81, 100
+]
+ 
+*/
+
+//2nd Difference
+// Ability to chain with other methods
+
+// const newArrayfor = arr
+//   .forEach((element) => element + element)
+//   .filter((x) => x > 9);
+// console.log(newArrayfor); // undefined
+
+// const newArrayMap = arr
+//   .map((element) => element + element)
+//   .filter((x) => x > 9);
+// console.log(newArrayMap); // [ 10, 12, 14, 16, 18, 20 ]
+
+//3rd Difference
+/*
+Mutability
+Mutability means ” Capacity or ability to change.”
+
+A mutable object is an object whose state can be changed after 
+its creation. Regarding mutability, how do the foreach() and map() 
+methods in Javascript behave?
+ 
+forEach() does not modify the array in which it is called. (However, the callback method can do this).
+
+map() does not modify the array in which it is called (although the callback method, if invoked, can do that).
+ 
+*/
+
+// let numbers = [5, 4, 3, 2, 1];
+// numbers.forEach((x) => console.log(x * x)); // 5 4 3 2 1
+// console.log(numbers);
+
+// // For Returning
+
+// let data = numbers.forEach((x) => x);
+// console.log(data); // undefined
+
+// numbers.forEach((x) => x); // undefined
+
+// // console.log(numbers.forEach((x) => x ** x));
+
+// // numbers.forEach((x) => console.log(x * x)); //
+
+// // console.log(numbers.map((x) => x ** x));
+// // numbers.map((x) => console.log(x * x));
+

2. Basic of JavaScript/1-12/8.js

@@ -0,0 +1,13 @@
+{
+  "name": "6.-types-in-javascript",
+  "version": "1.0.0",
+  "description": "",
+  "main": "1.js",
+  "type": "module",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC"
+}

2. Basic of JavaScript/1-12/9.js

@@ -0,0 +1,17 @@
+// Array At() Method
+// It accepts the index number and gives the element
+// of that specific index
+const arr = ["Java", "C", "C++", "Python", "Javascript"];
+
+console.log(arr.at(0));
+//              Index ==> Element (Java)
+console.log(arr.at(1));
+console.log(arr.at(2));
+console.log(arr.at(3));
+console.log(arr.at(4));
+console.log(arr.at(5)); // if there is no index
+//  then it will show undefined
+
+// Index ===> element
+
+// Note: It only returns a element of a specific index

3. Control Flow of JavaScript/1-20/1.js

@@ -0,0 +1,10 @@
+// Array FindIndex()
+// Array FindIndex Method Returns the First Element Index from ther
+// Array Which passes the test given in the defined in
+// the function
+
+const arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
+
+console.log(arr.findIndex((x) => x % 2 == 0)); // 2 index is 1
+
+// 2 is the first element from finding all even numbers and index 1

3. Control Flow of JavaScript/1-20/10.js

@@ -0,0 +1,3 @@
+// Array findLastIndex()
+//  Depcrated Not In Work
+//  that is no longer supported or maintained