Day 12 js interview

Author: nilajcoder

JavaScript Interview/Day 12/demo.js

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+
+
+/*
+1. What is the Comma Operator?
+The comma operator allows multiple expressions to be evaluated in a single statement.
+ It evaluates each expression from left to right, but it only returns the value of the last expression.
+
+1. const x=(4,5,6)
+console.log("x =",x)//6
+console.log(typeof x)//number
+
+
+2. 
+function abc() {
+}
+
+var abc
+
+console.log(abc);//funtion :abc
+
+
+
+3. console.log(n.toString(8));
+n.toString(8) converts the number n (which is 10) into its string representation in base 8 (octal).
+
+In base 8, 10 in decimal is represented as 12 (because 1 * 8^1 + 2 * 8^0 = 10 in decimal).
+
+Output: 12
+
+So, the second log prints "12", which is the base 8 (octal) representation of 10.
+
+
+let n = 10;
+
+console.log(n.toString());//10
+
+console.log(n.toString(8));//12
+
+
+4. 
+function a() {
+    console.log('hai');
+    
+}
+
+console.log(a());//hai undefined
+
+
+
+function a() {
+    console.log('hai');
+    return 10
+}
+
+console.log(a());//hai 10
+
+
+
+5.  function abc() {
+    console.log('xyz');
+}
+
+console.log(abc.name); // abc
+
+
+6. 
+console.log(abc)//Ref Error
+
+
+
+7.
+Why the Difference?
+var: Variables declared with var are function-scoped or globally-scoped
+ (if declared outside any function). When declared in the global scope, 
+ they are added to the window object in browsers.
+
+let and const: Variables declared with let or const have block scope 
+(limited to the block, statement, or expression in which they are defined) and are not added to the global object.
+
+var abc = 100;
+let xyz = 200;
+
+console.log(window.xyz); // undefined REF error
+console.log(window.abc); // 100
+
+
+
+8.
+
+Key Points:
+Strict mode makes arguments and function parameters (n1, n2) independent, meaning changes to parameters don't 
+reflect in the arguments object.
+The arguments object holds the original values passed to the function (100 and 200),
+ even though you modified the parameters inside the function.
+Let me know if you'd like further clarification!
+
+function abc(n1, n2) {
+    'use strict'
+    n1 = 300;
+    n2 = 400;
+    return arguments[0] + arguments[1];
+}
+
+console.log(abc(100, 200));//300
+
+
+
+
+function abc(n1, n2) {
+    
+    n1 = 300;
+    n2 = 400;
+    return arguments[0] + arguments[1];
+}
+
+console.log(abc(100, 200));//700
+
+9. new xyz();//Ref Error
+
+function abc() {
+    console.log('hai');
+}
+
+class xyz {
+}
+
+
+
+10. const abc = 10 + isNaN(2) ? 100 : 200;//10+0?100:200   10?100:200
+console.log(abc);//100
+
+
+
+11. 
+console.log(10 == 10); // true
+console.log(10 == 10 == 10); // false true==10  1==10 
+console.log(10 == 10 == 0); // false     1==0
+
+
+
+12. 
+
+console.log(parseInt(''))//NAN
+console.log(Number(''))//0
+console.log(parseInt("Nil"))//NAN
+
+console.log(parseInt(true))//NAN
+console.log(parseInt(false))//NAN
+
+console.log(Number(true))//1
+console.log(Number(false))//0
+
+*/
+
+
+