How to do math on strings in JavaScript?

Question

var string = "2+3-1";
document.write(string);

In the code above, I have a string with digits and plus and minus operators. I want to calculate the string when i want to display it. I mean, when i want to dispaly, it should calculate and show 4. I tried to convert them to number but gives error.

Answer 1

You can use the built in method eval()

Note: Using eval() is never recommended. You should use some kind of external library like https://mathjs.org/

var string = "2+3-1";
document.write(eval(string));