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JavaScript JavaScript Loops, Arrays and Objects Simplify Repetitive Tasks with Loops The Refactor Challenge, Part 2

Posted by Daniel Muvdi
Daniel Muvdi
5,262 Points

My solution was this

Here is my code could be better but was similar to the instructor. :)

var html = '';

function random256 () {
return Math.floor(Math.random() * 256 );
} 

for (var i = 0; i <= 100; i +=1 ) {
rgbColor = 'rgb(';
rgbColor += random256 () + ',';
rgbColor += random256 () + ',';
rgbColor += random256 () + ')';
html += '<div style="background-color:' + rgbColor + '"></div>';
   }
document.write(html);

but in this example is way faster this way. ( i know we are learning the concepts)

var html = '';
for (var i = 1; i <= 100; i += 1) { 
red = Math.floor(Math.random() * 256 );
green = Math.floor(Math.random() * 256 );
blue = Math.floor(Math.random() * 256 );
rgbColor = 'rgb(' + red + ',' + green + ',' + blue + ')';
html += '<div style="background-color:' + rgbColor + '"></div>';
}
document.write(html);

2 Answers

Steven Parker
Steven Parker
229,744 Points
Steven Parker
Steven Parker
229,744 Points

It is a bit faster, but at the cost of violating the "DRY" principles and using repeated code.

On the other hand, this is even faster, and still observes the "DRY" principles:

var html = '';
var rc = () => Math.floor(Math.random() * 256);
for (var i = 1; i <= 100; i++) {
    html += '<div style="background-color:' +
       'rgb(' + rc() + ',' + rc() + ',' + rc() + ')' + '"></div>';
}
document.write(html);
Daniel Muvdi
Daniel Muvdi
5,262 Points

Hey i try that and didn't work for me. now i see why. thanks for your answer. what s the principle of var rc = () => ? I'm not yet in that part of the curse.

i try it normal var rc = Math.floor(Math.random() * 256); , but didn't work so the key was () => i have to lern more about that.

Steven Parker
Steven Parker
229,744 Points
Steven Parker
Steven Parker
229,744 Points

That's an arrow function, it's essentially the same as your "random256" function with a more concise syntax.

Daniel Muvdi
Daniel Muvdi
5,262 Points
Daniel Muvdi
Daniel Muvdi
5,262 Points

Yes i found a good lecture on that function here https://codeburst.io/javascript-arrow-functions-for-beginners-926947fc0cdc

I will check it out thanks.