I have a valid mathematical expression that just needs to be ended with some closing parentheses for eval() to work. For this, I can find the unclosed parentheses in the expression and append closing parentheses until the unclosed parentheses match with the closing parentheses.

This is what I have done:

let expression = `3 * 1 * (4 - 1 - (5 * 9 * (2 - 6 / 5 + (4 - 1 - (5 * 9 * (2 - 6 / 5 - 
                  (4 - 1 - (5 * 9 * (2 - 6 / 5 + (4 - 1 - (5 * 9 * (2 - 6 / 5`;

const openingParenthesisCount = (expression.match(/[(]/g) || []).length;
const closingParenthesisCount = (expression.match(/[)]/g) || []).length;
let unclosedParenthesisCount =
  openingParenthesisCount - closingParenthesisCount;

try {
  console.log(eval(expression));
} catch (error) {
  // Append closing parentheses until all the parentheses are closed
  while (unclosedParenthesisCount) {
    expression += ")";
    unclosedParenthesisCount--;
  }
}

// Valid expression
console.log(eval(expression));

I have used a test expression for this and it works, but if the expression is longer, it may take some time (but eventually will show the result).

Is there an easier/ faster method to achieve this?