How do I calculate the value of a string variable in JS

Question

If I have a variable with the value "1+2+3", how can I convert this to a number? (in this case it would be 6)

This is my full code:


var screen = 0

function buttonActivation(button) {
    if (button == '=') {
        console.log(screen)
        var result = parseFloat(screen)
        document.getElementById('screenLine2').innerHTML = result
    } else if (screen == 0) {
        screen = `${button}`
    } else {
        screen = `${screen}${button}`
    }
    document.getElementById('screenLine1').innerHTML = screen
}

function clearScreen() {
    screen = 0
    document.getElementById('screenLine1').innerHTML = screen
    document.getElementById('screenLine2').innerHTML = ''
}

@Yousaf The code I posted is where I need it, I posted it so that people could see what I currently have. — DarkKillerXL, May 18 '20 at 07:50

score 1 · Accepted Answer · answered May 17 '20 at 09:41

1

What your title suggests is achievable with eval() function, but your question text is not clear. Also, this function has security risks that should be considered. Please consider alternative solutions.

var stringVariable = "1+2+3"
console.log(eval(stringVariable))

answered May 17 '20 at 09:41

Masoud Tahmasebi

423
6
22

please see [Never Use Eval](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/eval#Never_use_eval!). You should not provide a solution that you yourself pointed out that its a security risk – Yousaf May 17 '20 at 09:53

How do I calculate the value of a string variable in JS

1 Answers1