Simple Calculator

Input string expression and calculate the result.

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How it works

This tool takes a string expression like "1+2*3". Wraps it into a function: new Function("return " + input). Executes and returns the result.

If the input is invalid, it throws an error.

function runExpression(input) {
  if (typeof input !== "string" || input.trim() === "") {
    throw new Error("Input must be a non-empty string.");
  }

  try {
    // Use Function constructor to safely evaluate
    const result = new Function("return " + input)();
    return result;
  } catch (e) {
    throw new Error("Invalid expression: " + e.message);
  }
}

If the input is invalid, it throws an error.