Basic-Math-dd-or-Subtract.js

/* In this kata, you will do addition and subtraction on a given string. The return value must be also a string.

Note: the input will not be empty.

Examples
"1plus2plus3plus4"  --> "10"
"1plus2plus3minus4" -->  "2"

*/

// solution

function calculate(str) {

    return eval(str.replace(/plus/gi, '+').replace(/minus/gi, '-')).toString();
  }