Add anonymous function return to array push

Question

How can I push the value return of anonymous function into the array. I have tried with this code but it not work. Where was I wrong

for (var i = 0; i < num; i++) {
        //get ramdom color
        // arr.push(randomColor());
        arr.push(function() {
            //pick a "red" from 0 - 255
            var r = Math.floor(Math.random() * 256);
            //green 0 - 255
            var g = Math.floor(Math.random() * 256);
            //blue 0 -255
            var b = Math.floor(Math.random() * 256);

            return "rgb" + "(" + r + ", " + g + ", " + b + ")";
        });
    }

I have written randomcolor() already but I just want to try Anonymous function. Thank you. — Thai Hoc Ha Nguyen
– Thai Hoc Ha Nguyen, Commented Jul 17, 2017 at 15:58

Nisarg Shah · Accepted Answer · 2017-07-17 15:45:55Z

1

Here's how you could do it:

for (var i = 0; i < num; i++) {
        //get ramdom color
        // arr.push(randomColor());
        arr.push(function() {
            //pick a "red" from 0 - 255
            var r = Math.floor(Math.random() * 256);
            //green 0 - 255
            var g = Math.floor(Math.random() * 256);
            //blue 0 -255
            var b = Math.floor(Math.random() * 256);

            return "rgb" + "(" + r + ", " + g + ", " + b + ")";
        }()); // Note the two brackets.
    }

Note the two brackets in second last line. They are meant to execute the function right away.

Be careful with such a pattern though. It is easy to confuse the reader with such code. You could rather use something such as:

function getRandomColor() {
    //pick a "red" from 0 - 255
    var r = Math.floor(Math.random() * 256);
    //green 0 - 255
    var g = Math.floor(Math.random() * 256);
    //blue 0 -255
    var b = Math.floor(Math.random() * 256);

    return "rgb" + "(" + r + ", " + g + ", " + b + ")";
}

for (var i = 0; i < num; i++) {
    //get ramdom color
    // arr.push(randomColor());
    arr.push(getRandomColor());
}

answered Jul 17, 2017 at 15:45

Nisarg Shah

14.6k6 gold badges38 silver badges58 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Thai Hoc Ha Nguyen Over a year ago

I already have written the function getRandomColor but I just want to try it with an anonymous function.

Nisarg Shah Over a year ago

Alright. Then the first sample does the job for you.

Bwaxxlo · Accepted Answer · 2017-07-17 15:49:47Z

1

No need to complicate this:

for (var i = 0; i < num; i++) {
    //get ramdom color
    //pick a "red" from 0 - 255
    var r = Math.floor(Math.random() * 256);
    //green 0 - 255
    var g = Math.floor(Math.random() * 256);
    //blue 0 -255
    var b = Math.floor(Math.random() * 256);
    var colour = "rgb" + "(" + r + ", " + g + ", " + b + ")";
    arr.push(colour)
}

answered Jul 17, 2017 at 15:49

Bwaxxlo

1,88013 silver badges19 bronze badges

Comments

kind user · Accepted Answer · 2017-07-17 15:46:22Z

0

You didn't call these functions inside the loop.

let arr = [];
let num = 3;

for (let i = 0; i < num; i++) {
  arr.push((() => {
    let r = Math.floor(Math.random() * 256);
    let g = Math.floor(Math.random() * 256);
    let b = Math.floor(Math.random() * 256);

    return "rgb" + "(" + r + ", " + g + ", " + b + ")";
  })());
}

console.log(arr);

answered Jul 17, 2017 at 15:46

kind user

42k8 gold badges69 silver badges78 bronze badges

Collectives™ on Stack Overflow

Add anonymous function return to array push

3 Answers 3

2 Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

2 Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related