Prevent Object Mutation

JavaScript
1

what is the mistake i have done in this coding ?? its not working help me

Your code so far


function freezeObj() {
  "use strict";
  const MATH_CONSTANTS = {
    PI: 3.14
  };
  // change code below this line
  MATH_CONSTANTS.PI = 3.14;

  // change code above this line
  try {
    MATH_CONSTANTS.PI = 99;
  } catch (ex) {
    console.log(ex);
  }
  return MATH_CONSTANTS.PI;
}
const PI = freezeObj();

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3359.181 Safari/537.36.

Link to the challenge:
https://learn.freecodecamp.org/javascript-algorithms-and-data-structures/es6/prevent-object-mutation