[SPOILERS] What way did you solve this? - "Confirm the ending"

JavaScript
1

Hey guys, I’m currently working my way through the algorithm section and its very rewarding coming up with a way to solve any of the problems.

I’ve just solved the ‘Confirm the ending’ algorithm challenge and I used some code that did the job but I have a feeling it was probably not the straightforward way of doing it.

I was wondering which way you solved it and what your code looked like, this is mine:

function confirmEnding(str, target) {
  // "Never give up and good luck will find you."
  // -- Falcor
  var arr = str.split(" "); //split the string up into an array of words
  var lastWord = arr[arr.length-1];
  if (lastWord.substr(-target.length) === target) {
    return true;
  }
  return false;
}


confirmEnding("Bastian", "n");

Interested to here how you solved this problem!

2

I cleaned up your code.
You need to use triple backticks to post code to the forum.
See this post for details.

Also, here’s my solution:


function confirmEnding(str, target) {
  // "Never give up and good luck will find you."
  // -- Falcor
  return target === str.substr(str.length - target.length, str.length);
}

confirmEnding("Bastian", "n");

It’s an old solution (which dates back to the day I started FCC).

I tried this again differently:


function confirmEnding(str, target) {
  // "Never give up and good luck will find you."
  // -- Falcor
  return new RegExp(target + '$').test(str);
}

confirmEnding("Bastian", "n");
3 
function confirmEnding (str, target) {
  return str.endsWith(target);
}
// but it won't work everywhere : 
// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/endsWith#Browser_compatibility

another way, using slice :

function confirmEnding(str, target) {
  
  return str.slice(-target.length) === target;
}
1 Like
4

This is the very simple solution I came up with-

function confirmEnding(str, target) {

  var subStr = str.substring(str.length-target.length);
  return subStr===target;
}

confirmEnding("Bastian", "n");
5

There’s never a need to do an if else statement that returns true or false when a boolean is returned by a boolean statement alone.

I did this:

return str.lastIndexOf(target) + target.length === str.length;

But I like @Omegga’s use of slice best

2 Likes
6 
    function confirmEnding(str, target) {
      var result = str.substr(str.length-target.length,str.length);
      if(result==target)
        return true;
      else
        return false;
    }

    confirmEnding("Bastian", "n");
7

I’m trying to make sense of your parenthesis equation…

(str.length - target.length, str.length);

What does this do to the code?

8

Those are the arguments to the str.substr call.

str.substr(str.length - target.length, str.length)

The first argument, str.length - target.length, marks where the substring in str should start. The second argument, str.length, tells how long the substring should be.

I should have used target.length for the second argument instead, since the substring I needed to get has the same length as target.

9

This is how I solved this problem. Just giving an alternative.

function confirmEnding(str, target) {
// “Never give up and good luck will find you.”
// – Falcor
return str.substr(target.length * -1, target.length) === target;
}

confirmEnding(“Bastian”, “n”);

10 
function confirmEnding(str, target) {
 return str.substr(-target.length) === target;
}
11

This is my solution

function confirmEnding(str, target) {
  // "Never give up and good luck will find you."
  // -- Falcor
  
  //First: Target strign length
  
  var targetLength = target.length;
  
  // Second: extract size caracters
  var position = str.length - target.length;
  
  var extractStr = str.substring(position);
  
  // Third: Compare target with extract
  
  if (extractStr === target) return true;
  
  return false;
}

confirmEnding("Bastian", "n");
12 
function confirmEnding(str, target) {
  return str.substr(-target.length, target.length) == target;
}

confirmEnding("Bastian", "n");
13

Can you explain your code?