Javascript splice function

Question

0.00/5 (No votes)

See more:

If i put var right on the bottom of the left variable , it returns empty string but it works fine when i declare it before left.

Why?

What I have tried:

<pre>let list = [1,3,5,2,9,4,6,7]

function mergeSort(list){
  if (list.length<2){
    return list
  }
  console.log(list);
  let mid =Math.floor((list.length)/2) ;
  console.log(mid);
   var right = list.splice(mid);
  var left = list.splice(0,mid); 


  
  console.log(left,right);
  return merge(mergeSort(left),mergeSort(right));

 
}
function merge(left,right){
let array= []
while(left.length && right.length){
  if (left[0]<right[0]){
  array.push(left.shift())
}
else {
  array.push(right.shift())
}
}
return [...array,...left ,...right]
}
console.log(mergeSort(list));

Posted 28-Jan-23 15:52pm

Jp Singh 2023

Updated 28-Jan-23 18:50pm

Add a Solution

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

OriginalGriff · Answer 1 · 2023-01-28T18:50:00

If in doubt, read the documentation: JavaScript Array splice() Method[^]
There you will find the cause of your problem:

Quote:
The splice() method overwrites the original array.

A quick test proves that:

HTML

<!DOCTYPE html>
<html>
<body>

<h2>JavaScript Arrays</h2>

<p>The Array.splice() method adds and removes array elements:</p>

<p id="demo"></p>
<p id="left"></p>
<p id="right"></p>

<script>
var fruits = ["Banana", "Orange", "Apple", "Mango"];
document.getElementById("demo").innerHTML = fruits;
let mid = Math.floor((fruits.length)/2) ;
var right = fruits.splice(mid);
document.getElementById("right").innerHTML = fruits;
var left = fruits.splice(0, mid); 
document.getElementById("left").innerHTML = fruits;
</script>
</body>
</html>