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    =================================================================== Q: WHAT TYPE OF DATA CAN STORE IN AN ARRAY? ============================================ ARRAYS CAN ALLOW TO DEFINE WITH ANY TYPE OF THE DATA LIKE: WITH PRIMITIVE TYPES WITH NON-PRIMITIVE TYPES WITH FUNCTIONS. let array1 = [10,20,30,40,50]; // array with numbers let array2 = [[1,3,5,7],[2,4,6,8]]; // array with arrays let array3 = [100,true,'A',[100,200,300]]; let array4 = [function(){console.log("Hi")},function(){console.log("Good Morning")}, function(){console.log("Welcome To Ashok IT")}]; console.log(array1[0]) console.log(array2[1]) console.log(array2[1][2]) console.log(array3[3]) console.log(array4[0]); ====================================================== Q: Why we need to define arrays with functions? =============================================== ==> to handle callback mechanism ==> callback mechanism is a technique where function will execute according to the situation. ["admin",function(){document.write("Login Success")},function(){document.write("Invalid data")}]; Array destruction: ================== var values = [10,20,30,40,50]; // accessing array elements without array destrcution console.log(values[0]); console.log(values[1]); console.log(values[2]); console.log(values[3]); console.log(values[4]); // accessing array elements with array destrcution var [v1,v2,v3,v4,v5] = values console.log(v1); console.log(v2); console.log(v3); console.log(v4); console.log(v5); ========================== var authorize = ["admin123",function(){console.log("Login Success")},function(){console.log("Login Fail")}]; // array destrcution var [password,success,failure] = authorize; var Yourpassword = "admin123"; if(Yourpassword == password){ success(); } else{ failure(); } =========================================== Anonymous Function: =================== ==> Name less function function sumTwoNumbers(a,b){ var result = a+b; console.log("The Sum = ",result); } const message = function(){ console.log("Hi"); } sumTwoNumbers(100,200); message(); x = sumTwoNumbers x(2000,3000); ========================================= How to add elements into an array: ================================== push(): ====== ==> can able to add an element into an array at the end. Syntax: array_name.push(element); var a = []; console.log("The Array a = ",a); a.push(100); a.push(200); a.push(300); console.log("The Array a = ",a); // do we add more than one element? a.push(400,500,600,700); console.log("The Array a = ",a); ============================================================ unshift(): ========== ==> can be used to add elements into an array at the beginning. Syntax: ArrayName.unshift(element); var a = []; console.log("The Array before the unshift operation = "); console.log(a); a.unshift(1.2); a.unshift(2.4); a.unshift(4.9); console.log("The Array after the unshift operation = "); console.log(a); a.unshift(100,200,300); console.log("The Array after the unshift operation = "); console.log(a); ================================================= splice(): ========= ==> can use to add an element at the specified index of an array. Syntax: array-name.splice(index, count, element) here: index ==> at which index the element want to add count ==> the number of elements at the specified index want to remove element ==> element value var a = [100,111,200,222,300,333]; console.log("Before the Splice Operation:") console.log("The Array = ",a); a.splice(2,0,"Mango"); console.log("After the Splice Operation:") console.log("The Array = ",a); a.splice(3,3,"Apple"); console.log("After the Splice Operation:") console.log("The Array = ",a); a.splice(2,2,"Hi","Hello","Good Morning","Good Afternoon"); console.log("After the Splice Operation:") console.log("The Array = ",a);