Basic JavaScript: Use Recursion to Create a Range of Numbers - const keyword

JavaScript
1

I have a very specific question in regards to how the const declaration of our result array plays into solving this. The const declaration isn’t needed here but an earlier example of a similar problem also used a const declaration and it works fine.

function rangeOfNumbers(startNum, endNum) {
  if(startNum === endNum) {
    return [startNum];
  } else {
    const result = rangeOfNumbers(startNum+1, endNum);
    result.unshift(startNum);
    return result;
  }
};

The const declaration creates a read-only reference to a value but the value is not immutable. Now when we start working down our call-stack each const result declaration will be set to the value of what is returned from rangeOfNumbers. Does this work because each function has it’s own “version” of const result?

2

Exactly. The variables in each function call are in their own separate scope.

1 Like
3

1/2 month after graduating with a CS degree I’m asking questions about variables in different function calls, brother almighty.

Thank you Jeremy!

1 Like
4

Recursion is a tricky thing to keep straight

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5

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