arrays and objects in depth

Author: nainimaru

02_basics/01_arrays.js

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+//array
+//PART 1
+
+const myArr = [0, 1, 2, 3, 4, 5]
+
+const myHeroes= ["shaktiman", "naagraj"]
+
+const myArr2= new Array(1,2,3,4)
+//console.log(myArr[1]);
+
+// array methods
+
+//myArr.push(6)
+//myArr.pop()
+
+//myArr.unshift(9)    //adds 9 in the beginning
+//myArr.shift()   //removes first element
+
+//console.log(myArr.includes(9));
+//console.log(myArr.indexOf(3));
+
+const newArr= myArr.join()    //convert to string
+
+//console.log(myArr);
+//console.log(typeof newArr);
+
+//slice, splice
+
+//console.log("A ", myArr);
+
+const myn1 = myArr.slice(1, 3)  //will show arr including index 1 and 2 only
+
+//console.log(myn1);
+//console.log("B ", myArr);  //array remains saim as original
+
+
+const myn2 = myArr.splice(1, 3)   //will show arr with element of index 3 as well
+//console.log("C ", myArr);  //elements spliced will be removed
+//console.log(myn2);  
+
+
+//PART 2
+
+const marvel_heros= ["thor", "Ironman", "Spiderman"]
+const dc_heroes= ["superman", "flash", "batman"]
+
+// marvel_heros.push(dc_heros)
+
+// console.log(marvel_heros);
+// console.log(marvel_heros[3][1]);
+
+// const allHeros = marvel_heros.concat(dc_heros)
+// console.log(allHeros);
+
+const all_new_heros = [...marvel_heros, ...dc_heros]
+
+// console.log(all_new_heros);
+
+const another_array = [1, 2, 3, [4, 5, 6], 7, [6, 7, [4, 5]]]
+
+const real_another_array = another_array.flat(Infinity)
+console.log(real_another_array);
+
+console.log(Array.isArray("naini"))
+console.log(Array.from("naini"))
+console.log(Array.from({name: "naini"})) //returns empty array, need to mention keys or values
+
+let score1 = 100
+let score2 = 200
+let score3 = 300
+
+console.log(Array.of(score1, score2, score3));

02_basics/arrays.js

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+//PART 1
+
+//singleton  -constructor se banega toh object humesha singleton banega
+//Object.create  -constructor method
+
+//object literals
+const mySym = Symbol("key1")
+
+const JsUser = {
+    name: "Naini",
+    "full name": "Naini Maru",
+    [mySym]: "mykey1",    //need to put in square brackets for symbols
+    age: 20,
+    location: "Indore",
+    email: "nainimaru@gmail.com",
+    isLoggedIn: false,
+    lastLoginDays: ["Monday", "Saturday"],
+}
+
+//console.log(JsUser.email);
+//console.log(JsUser["email"]);
+//console.log(JsUser["full name"]);
+//console.log(JsUser[mySym]);
+
+JsUser.email= "naini@google.com"
+
+//Object.freeze(JsUser)   //to lock the info and not be allowed to make changes
+
+JsUser.email= "maru@google.com"
+//console.log(JsUser.email);
+
+JsUser.greeting = function(){
+    console.log("Hello Js User");
+}
+JsUser.greetingTwo = function(){
+    console.log(`Hello Js User, ${this.name}`);
+}
+
+console.log(JsUser.greeting());
+console.log(JsUser.greetingTwo());

02_basics/objects.js

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+//PART 2
+
+//const tenderUser = new Object()  -singleton
+const tinderUser= {}    //-not singleton
+
+tinderUser.id= "123abc"
+tinderUser.name= "Naini"
+tinderUser.isLoggedIn= false
+
+//console.log(tinderUser);
+
+const regularUser= {
+    email: "some@gmail.com",
+    fullname: {
+        userfullname: {
+            firstname: "Naini",
+            lastname: "Maru",
+        }
+    }
+}
+
+//console.log(regularUser.fullname.userfullname.lastname);
+
+const obj1 = {1: "a", 2: "b"}
+const obj2 = {3: "a", 4: "b"}
+const obj4 = {5: "a", 6: "b"}
+
+// const obj3 = { obj1, obj2 }
+//const obj3 = Object.assign({}, obj1, obj2, obj4)
+//console.log(obj3);
+//console.log(obj1);
+
+const obj3 = {...obj1, ...obj2}
+// console.log(obj3);
+
+
+const users = [
+    {
+        id: 1,
+        email: "h@gmail.com"
+    },
+    {
+        id: 1,
+        email: "h@gmail.com"
+    },
+    {
+        id: 1,
+        email: "h@gmail.com"
+    },
+]
+
+users[1].email
+// console.log(tinderUser);
+
+// console.log(Object.keys(tinderUser));    //-results in an array
+// console.log(Object.values(tinderUser));
+// console.log(Object.entries(tinderUser));
+
+// console.log(tinderUser.hasOwnProperty('isLoggedIn'));
+
+
+// ++++++++++++++++++ PART 3 +++++++++++++++++++++++
+
+const course = {
+    coursename: "js in hindi",
+    price: "999",
+    courseInstructor: "hitesh"
+}
+
+// course.courseInstructor
+
+const {courseInstructor: instructor} = course
+
+// console.log(courseInstructor);
+console.log(instructor);
+
+// {
+//     "name": "hitesh",
+//     "coursename": "js in hindi",
+//     "price": "free"
+// }
+
+[
+    {},
+    {},
+    {}
+]
+