Oh That Trick

LET Keyword The  let  keyword declares a local variable in the block scope. Normally  if statements don’t have scope, but now they do with  let . This also works for loops too. for Example :  var x = 1 ; if (x < 10 ) { let v = 1 ; v = v + 21 ; console .log (v); } console .log (v); //v is not defined CONST keyword A  const  or a constant declaration is where once, the variable is set you can’t change it. It’s read-only. For example :    const admin = "jain";    admin = "pardeep" //not allowed...readonly