Initial commit

Author: surujtv

.vscode/settings.json

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+{
+    "editor.fontFamily": "Cascadia Code",
+    "liveServer.settings.port": 5501
+}

Session01/01_ImpTheory/01_var&let&const.js

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+// We can differentiate var, let and const keywords as follows-->
+
+/*
+Short Overview---->
+1. Scope-> var doesn't have block scope it is globally scoped where 'let' and 'const' have block scope
+2. Re_Declare-> var can be redeclare where let and const can't be redeclare.
+3. Re_Initialization-> var and let can be redeclare unlike const.
+4. for const variables we have to initialize it at the time of declaration unlike var and let.
+*/
+
+//-------------------------- Practical Overview ----------------------------------------
+
+// -------------------------------------------------------------
+// 1. on the basis of "SCOPE"-->
+// var doesn't have block scope it is globally scoped where 'let' and 'const' have block scope
+// for example---->
+
+{
+    var fullName = 'Sandhya Dwivedi';
+    let DOB = '23/07/1999';
+    const age = 24.5;
+}
+// if we want to access these values outside the block output will be-->
+// console.log(fullName)   // Sandhya Dwivedi globaly scoped
+// console.log(DOB)    //  DOB is not defined due to block scope
+// console.log(age)    //  age is not defined due to block scope
+// *uncomment all consol.logs to see output
+
+// -------------------------------------------------------------
+
+// 2. on the basis of "REDECLARATION"-->
+// var can be redeclare where let and const can't be redeclare.
+// for Example var can be redeclare-->
+var fullName = 'Sandhya Dwivedi';
+var fullName = 'Sandhya Dwivedi';  
+console.log(fullName);  // last output--> Sandhya Dwivedi
+/* 
+let DOB = '23/07/1999'
+let DOB = '23/07/1999'  
+const age = 24.5;
+const age = 24.5;
+*/
+// We can't do this because let and const can't be redeclare it will throw an error 
+// *uncomment krke dekh sakte ho
+
+// -------------------------------------------------------------
+
+// 3. on the basis of "RE_INITIALIZATION"-->
+// var and let can be re-initialized unlike const--
+
+var fullName = 'Sandhya Dwivedi';
+fullName = 'sandhya.dwivedi.5454';
+console.log(fullName)   // output--> sandhya.dwivedi.5454
+
+let DOB = '23/07/1999';
+DOB = '23/07/2001';
+console.log(DOB)    // output--> 23/07/2001
+
+const age = 24.5;
+age = 24.6;
+console.log(age) // output --> throw an error - can't reassign values to const variables
+
+// -------------------------------------------------------------
+
+// 4. on the basis of "INITIALIZATION while Declaring variables"-->
+// for const variables we have to initialize it at the time of declaration unlike var and let
+// for Example-->
+
+// const myName;   //  we can't do this it will throw an error
+const myName = 'Surendra Jatav'
+
+let name;
+var name1;
+

Session01/01_ImpTheory/02_DataTypes.js

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+/*
+In JavaScript, there are several data types. The primitive data types are:
+
+String: Represents a sequence of characters. It is defined using either single quotes (' ') or double quotes (" ").
+let string1 = 'Hello World';
+let string2 = "Hello JavaScript";
+
+Number: Represents a numeric value. In JavaScript, there is only one number type, which can contain both integers and floating-point values.
+let num1 = 10; // Integer
+let num2 = 3.14; // Floating-point number
+
+Boolean: Represents a true or false value. It is commonly used in conditional expressions.
+let bool1 = true;
+let bool2 = false;
+
+Null: Represents a null value, which can be assigned to a variable. It represents an empty or non-existent value.
+let nullValue = null;
+
+Undefined: Represents an undefined value. In JavaScript, this value is automatically assigned to variables that have been declared but not initialized.
+let undefinedValue;
+console.log(undefinedValue); // Output: undefined
+
+Symbol: Represents a unique identifier or a symbol in JavaScript.
+let symbol1 = Symbol('description');
+
+BigInt: Represents an arbitrary large integer, larger than the maximum safe integer limit (2^53 - 1).
+let bigInt1 = 12345678901234567890n;
+
+*/
+
+/*
+Non-Premetive---->
+
+There is only one premetive data type that is called Object and Object are devided into three categories. 
+
+Object literals: 
+Represents a collection of properties and each property is a association between a unique key and a value.
+let object1 = 
+{ key1: 'value1', key2: 'value2' };
+
+Arrays : 
+Represents an ordered collection of items, where each item is a value and can be accessed by an index.
+let array1 = [1, 2, 3, 4, 5];
+
+Functions : 
+Represents a function or a reusable piece of code that can be defined once and called multiple times.
+function add(a, b) {
+ return a + b;
+}
+
+----------------
+
+NOTE: Date and Promises are also Object literals.
+Date: 
+Represents a specific moment in time.
+let currentDate = new Date();
+
+Promise: 
+Represents an object that represents an eventual completion or failure of an asynchronous operation and its resulting value.
+let promise1 = new Promise((resolve, reject) => {
+ setTimeout(() => {
+    resolve('Promise resolved');
+ }, 1000);
+});
+
+*/

Session01/01_ImpTheory/02_variables-JS.js

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+/*
+    Variable:
+    It is a reserved memory location.
+    It is used to store data of specific type.
+    var and let introduced in ECMAScript 5.
+    const and arrow function in ES6
+    
+    ---------------------------------------------------
+    
+    RAM:Random Access Memory
+        It is a temporary storage of data.
+    
+    =============================================== 
+    
+    Keywords:It is a reserved words which is used by compiler. whose definition is load in the memory of compiler.
+
+    ----------------------------------------------
+  
+    Javascript:It is used to make dynamic changes in a web page.
+        It supports OOPS(Object Oriented Programming Structure) features.
+        It is a programming language.
+    
+    =================================================
+    
+    Document: It represents a web page.
+    When we load a web page in a browser, automatically a document object is created.
+    By using document object we can directly access HTML elements using DOM.
+    DOM:
+    D:Document(.html)
+    O:Object(HTML Element,Node)
+    M:Modal(Tree Structure)  
+*/
+
+//PRACTICAL - 
+
+//name is a variable that stores a string.
+let name = 'Sandhya Dwivedi'  //let keyword is used for declaring variable with block scope.
+console.log('Name : ',name); // Output: Name : Sandhya Dwivedi

Session01/01_ImpTheory/03_Operators.js

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+// types of operators in js-->
+// arithmetic operator --> +,-,*,/,%, **(exponential or power)
+// assignment operator --> =
+// comparison operator --> ==, !=, > ,<, >=, <=,===(compare value and data types)
+// logical operator --> && (and), ||(or)
+// bitwise operators-->
+// NOT operator--> to flip the value
+// Shift operators-->
+// << is left shift and >> is right shift.
+
+// add string to integer
+
+// concatenation using '+' operator
+console.log("Hello " + "World");
+
+let x = 10;
++console.log("6" + x);
+// if we add any int to any number it will conver int to string by default
+
+//but when we use substraction it wil perform unlike addition
+console.log("6" - x); //output -4
+
+console.log("6" - -x); // output 16
+
+console.log("6" + +x); // output 610
+
+console.log("6" - +x); // output -4
+
+console.log("6" + -x); // output 6-10
+// first sign has higher preference where second is define number is negative or positive
+
+// console.log("6" + / x); not working
+
+// combined (compound) operators -
+/*
+    Addition assignment operator  (+=): a += b is equivalent to a = a + b.
+    Subtraction assignment operator (-=):  c -= d is equivalent to c = c – d.
+    Multiplication assignment operator (*=): e *= f is equivalent to e = e * f.
+    Division assignment operator (/=): g /= h is equivalent to g = g / h.
+    Modulus assignment operator (%=): i %= j is equivalent to i = i % j.
+    Exponentiation assignment operator  (**=): k **= l is equivalent to k = k**l.
+*/

Session01/01_ImpTheory/04_typeConversion.js

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+/*
+    Type Conversion in JS-->
+        Converting  one data type to another is called as Type conversion.
+        
+    Types of conversion --->
+    1. Implicit type conversion: 
+        - When we assign a value of one data type to another without explicitly converting it, JavaScript does the conversion for us.
+    2. Explicit  type conversion: (Manually)
+        using parseInt(), parseFloat() methods, Number() method and String() method we can convert one data type to another.
+*/
+
+
+// type conversions------>
+console.log("Hello " + "World");
+
+let x = 10;
+console.log("6" + x);
+// if we add any string to any number it will convert int to string by default (implicite conversion)
+
+//but when we use substraction it will perform unlike addition(Implicite conversion)
+console.log("6" - x);   //output -4
+
+console.log("6" - - x); // output 16
+
+console.log("6" + + x); // output 610
+
+console.log("6" - + x); // output -4
+
+console.log("6" + - x); // output 6-10  // first sign has higher preference where second is define number is negative or positive
+
+// console.log("6" + / x); not working
+
+console.log(x - + "6"); // output -4
+console.log(x - "6"); // output 4
+// subtraction sign convert string into number by-default
+// Addition operator concat strings if we try to add number to a string it will be concanated.
+
+//Some methods (explicit conversion)-------->
+//1. String()
+//2. Number()
+//3. Boolean()
+
+let type = 'Hello'  
+console.log(typeof type);
+
+type = Number(type);
+console.log(typeof type);
+console.log(type);  // Output--->NaN
+
+type = 32
+type = String(type);
+console.log(typeof type);
+console.log(type);
+
+// type = '' empty string will be marked as false
+type = 'Surendra'   //Output true
+type = Boolean(type)
+console.log(type)
+
+// type = 1 // all numbers except 0 will be marked as true
+type = 0    // Output false
+type = Boolean(type);
+console.log(typeof type);
+console.log(type);

Session01/01_ImpTheory/05_conditional_Statements.js

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+// Conditional Statements---->
+    
+// Syntax-->
+
+/*
+    1. if (condition){
+        code block to be executed if the condition is true;
+    }
+
+    //-------------------------------------------------------------
+
+    2. if (condition){
+        code block to be executed if the condition is true;
+    }else{
+        code block to be executed if the condition is false;
+    }
+
+    //--------------------------------------------------------------
+
+    it's called else_if ladder--> all condition will be checked one by one util get true condition.
+    
+    3. if(condition_1){
+        code block to be executed if the condition_1 is true;
+    }else if(condition_2){
+        code block to be executed if the condition_2 is true;
+    }else if(condition_3){
+        code block to be executed if the condition_3 is true;
+    }else if(condition_4){
+        code block to be executed if the condition_4 is true;
+    }else{
+        code block to be executed if none of the conditions are true;
+    }
+
+    //-------------------------------------------------------------
+
+    Switch_Case----->
+
+    let a = 5
+    switch (a){
+        case 1:{
+            console.log("one")
+            break;
+        }
+        case 3:{
+            console.log("three")
+            break;
+        }
+        case 5:{
+            console.log("five")
+            break;
+        }
+        default: {
+            console.log("Not in list");
+        }
+    }
+
+*/
+

Session01/01_ImpTheory/switchCase.js

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+let input = 1
+    switch (input){
+        case 1: {
+            console.log('January')
+            break;
+        }
+        case 2: {
+            console.log('feb')
+            break
+        }
+        case 3: {
+            console.log('march')
+            break
+        }
+        case 4: {
+            console.log('may')
+            break
+        }
+        case 5: {
+            console.log('jun')
+            break
+        }      
+        default: {
+            console.log("Not in list");
+        }
+    }
+