jquery - JavaScript split() method resulting in undefined - Stack Overflow

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I'm working on a simple program that will select a random string from an array.

I started with a predefined array, but about halfway through wondered if it wouldn't be simpler (or more elegant) to use a text file (.txt), since I have a bit over 1000 items.

I found this solution here (for which I take no credit) and it is working for me...

function readTextFile(file) {
    var items = [];
    var rawFile = new XMLHttpRequest();
    rawFile.open("GET", file, true);
    rawFile.onreadystatechange = function() {
        if(rawFile.readyState === 4)
        {
            if(rawFile.status === 200 || rawFile.status === 0)
            {
                var items = rawFile.responseText.split('\n');
                alert(items[0]);
            }
        }
    };
    rawFile.send(null);
}

readTextFile('source.txt');

...to an extent.

I want the array items[] to contain one line per item. In other words I want to split per new line. However, all array items are undefiend after items[0] when I use split('\n').

items[0] in the example above bees the first sentence, so that much is correct. If I want to alert items[1] I get undefined.

If I use some other split point, such as split(''), it works correctly, separating each character per item ONLY until the line breaks, after which point I get undefined again.

Let's say the first line of the .txt is "asd": so 'asd' is defined in array as :

items[0] = 'a'
items[1] = 's'
items[2] = 'd'
items[3] = undefined

This is what I would get. Where am I wrong?

Contents of text file:

asfe
asdasdasd
asdasd

fgfg

I'm working on a simple program that will select a random string from an array.

I started with a predefined array, but about halfway through wondered if it wouldn't be simpler (or more elegant) to use a text file (.txt), since I have a bit over 1000 items.

I found this solution here (for which I take no credit) and it is working for me...

function readTextFile(file) {
    var items = [];
    var rawFile = new XMLHttpRequest();
    rawFile.open("GET", file, true);
    rawFile.onreadystatechange = function() {
        if(rawFile.readyState === 4)
        {
            if(rawFile.status === 200 || rawFile.status === 0)
            {
                var items = rawFile.responseText.split('\n');
                alert(items[0]);
            }
        }
    };
    rawFile.send(null);
}

readTextFile('source.txt');

...to an extent.

I want the array items[] to contain one line per item. In other words I want to split per new line. However, all array items are undefiend after items[0] when I use split('\n').

items[0] in the example above bees the first sentence, so that much is correct. If I want to alert items[1] I get undefined.

If I use some other split point, such as split(''), it works correctly, separating each character per item ONLY until the line breaks, after which point I get undefined again.

Let's say the first line of the .txt is "asd": so 'asd' is defined in array as :

items[0] = 'a'
items[1] = 's'
items[2] = 'd'
items[3] = undefined

This is what I would get. Where am I wrong?

Contents of text file:

asfe
asdasdasd
asdasd

fgfg

• javascript
• jquery
• arrays
• split
• text-files

Share Improve this question Follow edited Jun 15, 2018 at 15:08 Tiago asked Jan 12, 2014 at 14:17 TiagoTiago 4,4901313 gold badges5050 silver badges7171 bronze badges 7

• I would use the array, count how many items in it, and then choose a random number between that amount and use it to call that array item. – pathfinder Commented Jan 12, 2014 at 14:22
• Oh, the random selection is not yet implemented but don't think I would have problems there (yet). For now I just want to guarantee all my array items are correct. Thank you though! – Tiago Commented Jan 12, 2014 at 14:29
• How you save that file? What is your text editor? I suspect the newline character isn't really \n. – Shadow Wizzard Commented Jan 12, 2014 at 15:37
• @Shadow Wizard: I suspect that too. I simply opened Notepad in Windows 7, typed some gibberish and saved it. Nothing else. – Tiago Commented Jan 12, 2014 at 15:41
• @Hubologist so that's weird, as it worked for me just fine. By the way, you need to run the code via IIS, running it as a local file (i.e. double clicking the HTML file in Windows Explorer) won't work. – Shadow Wizzard Commented Jan 12, 2014 at 15:53

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3 Answers 3

Sorted by: Reset to default 6

Try adding a String cast:

var items = String(rawFile.responseText).split('\n');

After some messing around with this I believe the problem is with your text editor that save the file with line breaks consisting of \r instead of \n, maybe Unix based server?

Anyway, you can replace those and it should work:

var rawText = rawFile.responseText;
rawText = rawText.replace(/\r\n/g, "\n");
rawText = rawText.replace(/\n\r/g, "\n");
rawText = rawText.replace(/\r/g, "\n");
var items = rawText.split('\n');

Probably because there's a blank row at the end of the responseText. Try using trim():

var items = rawFile.responseText.trim().split('\n');

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