Dynamic operators in javascript

Question

I currently have a large switch statement:

switch (arg) {
    case '+':
        equals = num1 + num2;
        break;
    case '-':
        equals = num1 - num2;
        break;
    case '*':
        equals = num1 * num2;
        break;
    case '/':
        equals = num1 / num2;
        break;
    case '%':
        equals = num1 % num2;
        break;
    default:
        error();
        return;
}

I wanted to know if there was anyway that I could do something like

equals = num1 /** Do the operation defined by a variable */ num2

Or something like that so I dont have the large switch statement I wasn't even sure where to start looking for something like this since things like "Dynamic operators in js" doesnt bring up what im looking for, any help is apreciated.

CherryDT · Accepted Answer · 2021-06-04 17:31:01Z

1

You can try using object with methods.

const operations = {
  "+": (a, b) => a + b,
  "-": (a, b) => a - b,
  "*": (a, b) => a * b,
  "/": (a, b) => a / b,
  "%": (a, b) => a % b,
};

const action = (op, a, b) => operations[op](a, b);

console.log(action("+", 5, 6));
console.log(action("/", 4, 2));

Creating function dynamically. Refer MDN for details and security concerns.

Alternavely, you can create function dynamically.

function createOperation(op) {
    return new Function('return arguments[0]' + op + 'arguments[1]'); 
}

const add = createOperation('+');
const sub = createOperation('-');

console.log(add(5, 6))
console.log(sub(5, 2))

edited Jun 4, 2021 at 17:31

CherryDT

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answered Jun 4, 2021 at 17:15

Siva Kondapi Venkata

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