freeCodeCamp/guide/english/certifications/javascript-algorithms-and-data-structures/es6/prevent-object-mutation/index.md

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Prevent Object Mutation

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Problem Explanation:

We need to prevent MATH_CONSTANTS value from changing.

Hint: 1

• Use Object.freeze(obj) to prevent object from being changed.

try to solve the problem now

Spoiler Alert!

Solution ahead!

Basic Code Solution:

    function freezeObj() {
      "use strict";
      const MATH_CONSTANTS = {
        PI: 3.14
      };

      Object.freeze(MATH_CONSTANTS);
      
      try {
        MATH_CONSTANTS.PI = 99;
      } catch( ex ) {
        console.log(ex);
      }
      return MATH_CONSTANTS.PI;
    }
    
    const PI = freezeObj();

Run Code

Code Explanation:

By using Object.freeze() on MATH_CONSTANTS we can avoid manipulating it.

Relevant Links

• Object.freeze()

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