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JavaScript

Russell Comer
Russell Comer
26,102 Points
Posted by Russell Comer
Russell Comer
26,102 Points

Variables or functions

I'm writing a little app basically just to practice on a small real world project and I'm curious if I should use variables instead of functions even if the functions are only a return statement. 

const accountBalance = document.getElementById("accountBalance");
const stockPrice = document.getElementById("stockPrice");

// Returns shares that are allowed per trade
function sharesPerTrade() {
    const amountPerTrade = accountBalance / 4;
    return Math.floor(amountPerTrade / stockPrice);
}

// Returns amount allowed per trade
function amountPerTrade() {
    return accountBalance / 4;
}

// Returns amount that should be calculated for limit and stop amounts
function getExitAmount(x) {
    return ((accountBalance * x) / sharesPerTrade()).toFixed(2);
}

// Returns a proposed limit selling price
function limitPrice() {
    return getExitAmount(.03) + stockPrice;

}

// Returns a proposed stop selling price
function stopPrice() {
    return stockPrice - getExitAmount(.01);

}

// Returns possible profit from the trade
function possibleProfit() {
    return (limitPrice() * sharesPerTrade()).toFixed(2);
}
Matthew Long
Matthew Long
28,407 Points
Matthew Long
Matthew Long
28,407 Points

Maybe use arrow functions? Might condense your code and improve readability.

const amountPerTrade => accountBalance / 4;
Steven Parker
Steven Parker
231,269 Points
Steven Parker
Steven Parker
231,269 Points

That's not arrow function syntax. But this would be:

const amountPerTrade = () => accountBalance / 4;
Matthew Long
Matthew Long
28,407 Points
Matthew Long
Matthew Long
28,407 Points

Good point. Steven. That's what happens when you comment on something at 3 in the morning.

1 Answer

Steven Parker
Steven Parker
231,269 Points
Steven Parker
Steven Parker
231,269 Points

One way to decide what to use is that variables store something, where functions do something.

For example, your function "amountPerTrade" returns the current value of "accountBalance" divide by 4. That's returning a value you get from doing something. If you had assigned a variable with this value, it continue to hold the same thing even if "accountBalance" changed later. But the function will always perform the calculation on the current value of "accountBalance".