Shadowing

here the redelecation of a variable shadow's the

var a = 100;
{  var a = 10;  let b = 20;  const c = 30;  console.log(a);  console.log(b);  console.log(c);}console.log(a); // a = 10

the output of this would be a = 100; a has shadowed the value here. but in case of let this does not happens