freeCodeCamp/guide/english/certifications/javascript-algorithms-and-data-structures/es6/declare-a-read-only-variable-with-the-const-keyword/index.md

title
Declare a Read-Only Variable with the const Keyword

Remember to use Read-Search-Ask if you get stuck. Try to pair program and write your own code

Problem Explanation:

Change all the variables to let or const and rename sentence.

Hint: 1

• Replace var for string with read-only const.

try to solve the problem now

Hint: 1

• Replace var in for loop to let.

try to solve the problem now

Hint: 1

• Common convention is to name const variables with ALL CAPS.

try to solve the problem now

Spoiler Alert!

Solution ahead!

Basic Code Solution:

    function printManyTimes(str) {
      "use strict";
      const SENTENCE = str + " is cool!";
      for(let i = 0; i < str.length; i+=2) {
        console.log(SENTENCE);
      }
    }
    printManyTimes("freeCodeCamp");

Run Code

Code Explanation:

By using const on sentence we can make it read-only and by using let on i inside the for loop we can avoid using var all together. For added code clarity we can also change sentence to SENTENCE to show that it is a constant.

Relevant Links

• const
• let

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