Turncate a string feedback

1

Hello guys! Would you like to check my code? It passes the tests, but im not sure if it’s, like, globally effective! Thanks for feedback.

function truncateString(str, num) {
  if (str.length > num && num>4) {
    var result = str.slice(-str.length, num-3)+ "...";
    return result;
  } else if (num <4) {
    var result2 = str.slice(-str.length, num)+"...";
    return result2;
  } else if (num >= str.length && num >4) {
    return str;
  } 
}

truncateString("Absolutely Longer", 2);
2

I’ll show you my version for it. Probably there is room from improvement here also! :slight_smile:

function truncateString(str, num) {
  if(str.length > num && num > 3)
    return str.substr(0, num-3) + "...";
  else if (num < 3)
    return str.substr(0, num) + "...";
  else
    return str;
}

truncateString("Absolutely Longer", 2);
3

Ok, so we were thinking almost the same way - i guess it’s right then :slight_smile:

4

If the code passes the tests everything is fine. Code works, you are done.

But anyway, I would like to show off a little :nerd:

You don’t need the last else if statement.
You don’t have to create result variables.

Code 
function truncateString(str, num) {
  if (str.length > num && num>4) {
    return str.slice(-str.length, num-3)+ "...";
  } else if (num <4) {
    return str.slice(-str.length, num)+"...";
  } 
    return str;
}

Now we see that both return statements are almost the same. Lets move the return statement outside the ifs and in if statements we will set the parts that change:

Code 
function truncateString(str, num) {
  var cut = 0,
      dots = '';
  if (str.length > num && num>4) {
    cut = 3;
    dots = '...';
  } else if (num <4) {
    dots = '...';
  } 
  return str.slice(-str.length, num - cut) + dots;
}

Well, we have both times set dots to '...'. Actually we need dots only if we change the input string, and we change the input string if it is longer than num. So if string is less or equal to num we can instantly return:

Code 
function truncateString(str, num) {
  if (str.length <= num) return str;
  var cut = 0;
  if (num>4) {
    cut = 3;
  } else if (num <4) {
  } 
  return str.slice(-str.length, num - cut) + '...';
}

Now we have an empty else, let’s throw it away:

Code 
function truncateString(str, num) {
  if (str.length <= num) return str;
  var cut = 0;
  if (num>4) {
    cut = 3;
  }
  return str.slice(-str.length, num - cut) + '...';
}

Then there is such thing as ternary operator, you can write if...else in one line: :

Code 
function truncateString(str, num) {
  if (str.length <= num) return str;
  var cut = num > 4 ? 3 : 0;
  return str.slice(-str.length, num - cut) + '...';
}

And so on…
Btw, -str.length is 0

:nerd: 
function truncateString(str, num) {
  return str.length <= num ? str : str.slice(0, num <= 3 ? num : num - 3) + '...';
}
3 Likes
5

@jenovs Love the way you cut it down step by step! :grinning: Very nice!

6

golden explanation sir :punch: