function isInterpolationBefore(before) {
  const result = { is: false, opsBetween: false };
  // Removing preceding operators if any
  const beforeOpsClipped = before.replace(/(\s*[+/*%-])+$/, "");

  if (beforeOpsClipped !== before) {
    result.opsBetween = true;
  }

  if (beforeOpsClipped[beforeOpsClipped.length - 1] === "}") {
    result.is = true;
  }

  return result;
}
Checks if there is an interpolation before the character.
Also checks if there is a math operator in between

@param {String} before - the input string that preceses the character
@return {Object} return
   {Boolean} return.is - if there is an interpolation
   {String} return.opsBetween - if there are operators in between