app.js

const resultElement = document.getElementById('result')
const input1 = document.getElementById('input1')
const input2 = document.getElementById('input2')
const submitBtn = document.getElementById('submit')
const plusBtn = document.getElementById ('plus')
const minusBtn = document.getElementById('minus')

plusBtn.onclick = function() {
    action = "+"
}

minusBtn.onclick = function() {
    action = "-"
}

function printResult (result){
    if(result < 0) [
        resultElement.style.color = 'red'
    ]
    else {
        resultElement.style.color = 'green'
    }
    resultElement.textContent = result    
}

function computeNumbersWithAction(inp1,inp2, actionSymbol) {
    const num1 = Number(inp1.value)
    const num2 = Number(inp2.value)
    // if(actionSymbol == '+') {
    //    return num1 + num2
    // } 
    // if (actionSymbol == '-') {
    //    return num1 - num2
    // }

    return actionSymbol == '+' ? num1 + num2 : num1 - num2
}


submitBtn.onclick = function (){
        const result = computeNumbersWithAction(input1, input2, action)
        printResult(result)

}