ERROR: Uncuaght TypeError: ar.splice is not a function

Question

/*
I have written the following code in JavaScript
The code opens a page where I can add a .txt-file
Then the code looks trough the program to find a linebreak ('\n')
When it findes this linebreak I would like the code to seperate this array and print it in the console, and then look for the next linebreak and repeat
But currently I am having problems with the ERROR in the quistion name (Uncaught TypeError: ar.splice is not a function)
I hope someone can help me with this and tank you for your time
*/

function fileReader(event)
{
var input = event.target;
var reader = new FileReader();
reader.onload = function()
{
var text = reader.result;
ar = reader.result.substring(0, 1377);
console.log(ar);
for(var i = 0; i < ar.length; i++)
{
console.log(ar[i]);
if(ar[i] == '\n')
{
ar = ar.splice(1, ar.indexOf('\n'));
console.log(ar);
}
}
}
reader.readAsText(input.files[0]);
}

Answer 1

Odd, this is working for me if I strip it down to:
ar = "somestring".substring(...);

alert(typeof ar) // string, no splice() error?

Perhaps you could check that reader.result is the expected type (like, not null or undefined or something)?

Answer 2

.splice() method is applicable only to arrays. Variable ar appears to store a string instead of an array. Perhaps you meant to use .slice() ?