Mastering JavaScript Functional Programming - Second Edition

Implementing operations

How would we write this binaryOp() function? There are at least two ways of doing so: a safe but long one and a riskier and shorter alternative. The first would require listing each possible operator. The following code does this by using a longish switch:

const binaryOp1 = op => { switch (op) {    case "+":      return (x, y) => x + y;    case "-":      return (x, y) => x - y;    case "*":      return (x, y) => x * y;    //    // etc.    //  }};

This solution is perfectly fine but requires too much work. The second is more dangerous, but shorter. Please consider this just as an example, for learning purposes; using eval() isn't recommended, for security reasons! Our second version would simply use Function() to create a new function that uses the ...