Ways to steer clear of using eval for converting strings to decimal values

Question

Ways to steer clear of using eval for converting strings to decimal values

I currently have the fraction "1/7" and I am looking to convert it into a decimal. While I know I can achieve this using eval("1/7"), I prefer not to use eval as it is considered harmful. Are there any alternative methods to accomplish this?

javascript eval

Answer 1

Answer №1

The evaluation function is not inherently harmful. Its negative impact only arises when applied to random strings of text without verifying the input first.

Answer 2

The evaluation function is not inherently harmful. Its negative impact only arises when applied to random strings of text without verifying the input first.

Answer 3

Answer №2

If you want to create your own function, it's actually quite simple and efficient:

function ParseFloat(sFloat) {
    var parts = sFloat.split("/");
    if (parts.length == 2) {
        var first = parseInt(parts[0], 10);
        var second = parseInt(parts[1], 10);
        if (!isNaN(first) && !isNaN(second))
            return first / second;
    }
    return NaN;
}

To use this function:

var s = "1/7";
alert(ParseFloat(s));

You can test it live here: http://jsfiddle.net/RK3zS/

Alternatively, if you prefer working with objects, you could define a class like this:

function DecimalFraction(first, second) {
    this.first = first;
    this.second = second;
    this.toString = function() {
        return first / second;
    }
}

Then you can create instances of this class like so:

var s = new DecimalFraction(3, 7);
alert(s);

I find this approach more elegant. You can see the updated jsFiddle here.

Answer 4

If you want to create your own function, it's actually quite simple and efficient:

function ParseFloat(sFloat) {
    var parts = sFloat.split("/");
    if (parts.length == 2) {
        var first = parseInt(parts[0], 10);
        var second = parseInt(parts[1], 10);
        if (!isNaN(first) && !isNaN(second))
            return first / second;
    }
    return NaN;
}

To use this function:

var s = "1/7";
alert(ParseFloat(s));

You can test it live here: http://jsfiddle.net/RK3zS/

Alternatively, if you prefer working with objects, you could define a class like this:

function DecimalFraction(first, second) {
    this.first = first;
    this.second = second;
    this.toString = function() {
        return first / second;
    }
}

Then you can create instances of this class like so:

var s = new DecimalFraction(3, 7);
alert(s);

I find this approach more elegant. You can see the updated jsFiddle here.

Answer 5

Answer №3

Seems like we're left with no other choice. Utilizing eval isn't necessarily a bad option. Alternatively, we could develop our own function to pinpoint values and perform calculations.

Answer 6

Seems like we're left with no other choice. Utilizing eval isn't necessarily a bad option. Alternatively, we could develop our own function to pinpoint values and perform calculations.

Answer 7

Answer №4

When dealing with decimal calculations exclusively:

text = "1/7";

numerator = text.subString(0, text.indexOf('/'));
denominator = text.subString(text.indexOf('/') + 1, text.length);

result = numerator / denominator;

Answer 8

When dealing with decimal calculations exclusively:

text = "1/7";

numerator = text.subString(0, text.indexOf('/'));
denominator = text.subString(text.indexOf('/') + 1, text.length);

result = numerator / denominator;

Answer 9

Answer №5

Give this a shot.

let txt = "1/7";
let result = new Function("return " + txt)()
console.log(result); // 0.14285714285714285

Answer 10

Give this a shot.

let txt = "1/7";
let result = new Function("return " + txt)()
console.log(result); // 0.14285714285714285

Ways to steer clear of using eval for converting strings to decimal values

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

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